Tag Archives: eave height

Plastic Vapor Barrier, PermaColumn, and a Fire Resistant Barrier

This Wednesday the Pole Barn Guru answers reader questions about use of 6 mil plastic vapor barrier in Michigan, if Hansen provides the option of a precast concrete pier to keep columns out of the ground, build heights, and “if anything needed between interior PVC panels, closed cell spray foam and the exterior metal siding.”

DEAR POLE BARN GURU: I have a pole barn that I am planning on insulating. The trusses are 2 foot on center and it has a shingled roof, the outside of the pole barn is steel. I live in Michigan and I was wondering if it is a good idea to put 6 mil plastic on the bottom of trusses before I hang steel on the ceiling. I will be blowing in insulation up there later. KAL in HUDSONVILLE

DEAR KAL: You are in Climate Zone 5A, so a ceiling vapor barrier is not required by Code. Building scientist and founding principal of Building Science Corporation Joe Lstiburek states, “Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days.” (More on degree days here: https://www.hansenpolebuildings.com/2022/11/what-is-degree-day/).

I would only recommend you installing a vapor barrier above your steel ceiling if you were to be considering blowing in cellulose insulation. Why cellulose? https://www.hansenpolebuildings.com/2022/10/cellulose-post-frame-attic-insulation/


DEAR POLE BARN GURU: Do you deal with post frame designs that: 1) use the precast column to keep wood out of the ground? 2) Deal with designs that are 20′ eave height to accommodate 2 story interiors. JONATHAN in ZANESVILLE

DEAR JONATHAN: We have had several clients provide their own pre-cast Permacolumns and they can be incorporated into our engineered designs. There is, however, a less costly option to explore: https://www.hansenpolebuildings.com/2018/04/perma-column-price-advantage/

We can engineer and provide up to 40 foot tall walls and three stories without needing fire suppression sprinklers, so 20 feet eave heights are not a problem.


DEAR POLE BARN GURU: Hello, my question, which I can’t seem to find a straight answer anywhere online. Is anything needed between interior PVC panels, closed cell spray foam and the exterior metal siding? The pole barn is located in southern Indiana. It’s used as a shop and being heated occasionally with a wood stove. BENJAMIN in INDIANA

DEAR BENJAMIN: As your PVC and closed cell spray foam are both flammable, I would use an intumescent fire proof paint on interior face of closed cell spray foam, then fill balance of wall cavity (if any) with rockwool batts. As an alternative to intumescent paint, you could place sheetrock between wall framing and PVC panels (panels will lay much smoother).

Why Are You Stuck on Bookshelf Girts?

Why in World are you Stuck on Bookshelf Girts?

Reader JAMES writes:

“Why in world are you stuck on bookshelf girts. For instance with ‘normal’ pole barns one could SPF the walls and roof and have almost no heat loss through the lumber. One could argue your “bookshelf girts” and purlins between trusses makes the building VERY close to a “normal home”. Do you offer a traditional style built pole barn as there MUST be savings to be had.”

Mike the Pole Barn Guru writes:
There are as many ways to structurally design post-frame buildings as there are providers and builders. Our way of building happens to be very similar to what would be considered as traditional style in Western states such as Washington, Idaho, Oregon, California, etc.

We do happen to offer buildings with columns every eight feet, trusses every four feet – however very few clients ever pick this as an option.

We are always looking at ways to make our post-frame buildings more efficient and DIY friendly, without sacrificing performance.

Worst part of post-frame construction (and least easily to detect challenges in advance) is having to dig holes. By widely spacing columns (usually most cost effective is every 12 feet), number of holes having to be dug is reduced by roughly 1/3rd from eight foot spacings.

Let’s examine R-value, calculated using Type 1, conventional method.

For sake of discussion, we will use an 18 eave height (tall enough for two stories in most instances). I’ve chosen a flash and batt method, for sake of cost effectiveness of insulation.

R-value through cavity

Air film – inside 0.67

½” gypsum wallboard – 0.56

2” closed cell spray foam – 14

5-1/2” Rockwool – 23

Exterior cladding – 0.5

Total R = 38.73

R-value through girts

Air film – inside 0.67

½” gypsum wallboard – 0.56

2×8 girt – 9.06

Exterior cladding – 0.5

Total R = 10.79

On an 18’ wall, there will be 8 girts with an area of 1.5” x 12’ x 8 = 9.6 sft (Square Feet)

Total area of a bay = 18’ x 12’ = 216 sft

Hence girts makeup 9.6 / 216 = 0.044 (4.4%) of wall

10.79 x 0.044 + 38.73 x 0.956 = 37.5

37.5 / 38.73 = 0.968 (96.8% of a wall without girts)

How about pieces in say a 60’ long wall?

Your “traditional”

Splash planks:  1/12’ 3/16’

Girts: Exterior 2×6 8/12’ 24/16’ Interior 2×4 8/12’ 24/16’
NOTE: Exterior girts may fail in deflection, especially at wall corners where forces are greater

Columns (excluding corners): 7/22’

Truss carriers (will vary depending upon roof load): 2×12 2/12’ 6/16’


Splash planks: 5/12’

Bookshelf girts: 2×8 40/12’

Girt blocking: 2×4 10/16’

Columns(excluding corners): 4/22’

Your version has me handling 74 pieces of lumber, with 1582 bd.ft. (board feet) of lumber vs. 59 pieces with 984 bd.ft. of lumber

Your wall sets outside of external wall girts at Building Line and creates an 8-1/2” thick framed wall. On a 40’ wide building, net framed interior clear width is 38’7”.

My wall has outside of columns at Building Line, so only 5-3/4” is lost on each side. Net framed interior clear width is 39’0-1/2”

In summary, my being stuck on bookshelf wall girts loses only 3.2% to thermal bridging, reduces holes to be dug (per sidewall) by 43%, reduces pieces to be handled 20% and board footage of lumber used by 38%, while delivering a greater net usable interior space.

Wall Height, What’s Included? and Drill Set Bracket Usage

Today the Pole Barn Guru answers reader questions about customizing the wall height to best “utilize sheet goods” on interior walls, what Hansen includes in a pole barn kit, and the practicality of using a drill set bracket for columns into an existing slab.

DEAR POLE BARN GURU: Once I save up the funds, I plan to have you guys design me a 28′ x 48′ pole barn with 12′ walls and 6/12 roof. Due to various reasons I will be foregoing metal siding and utilizing wood sheathing and siding for the exterior. I know you measure wall height from the bottom of skirt board, but is it possible to have 12′ walls from top of concrete floor to bottom of truss so as to efficiently utilize sheet goods on the interior walls? Also is 12′ post spacing possible? Thanks TROY in HONEOYE FALLS

DEAR TROY: Yes, we can design to give you a 12′ finished ceiling. Typically, your Building Designer will plan upon 12′ 1-1/8″ from top of slab to bottom of trusses. This allows for finished ceiling thickness (drywall, steel, etc.) and to be able to utilize 12′ drywall panels run vertically and be 1/2″ above your concrete. In most instances sidewall columns every 12 feet will be your most economical design solution (and minimizes number of holes having to be dug).


DEAR POLE BARN GURU: I was wondering what is including a pole barn kit? JOSHUA in LEBANON

DEAR JOSHUA: Our fully engineered post frame (pole barn) kits include: Mutli-page full size (24″ x 36″) engineer sealed structural plans, specific to your building, on your site, detailing location and connection of every structural member. Includes foundation design. Engineer sealed calculations to verify adequacy of each member and connection. The industry’s best fully illustrated Construction Manual. Unlimited Technical Support from a team who has actually built post frame buildings. All columns, pressure treated splash planks, wall girts, blocking, headers, jambs, roof trusses (and floor trusses where applicable), truss bracing, roof purlins, joist hangers, specialty connectors for trusses to columns, steel roofing and siding (or alternative claddings), steel trims, UV resistant closures for eaves and ridge, powder coated diaphragm screws to attach steel, doors and windows. In a nut shell – everything you need to successfully erect your own beautiful new building other than concrete, rebar and any nails normally driven from a nail gun.

Our Limited Lifetime Structural Warranty.


DEAR POLE BARN GURU: I have an existing concrete slab with extra thick edges that once housed a quonset before a tornado in the 1980s destroyed it. I have bolted on brackets intending to use the glued columns that I purchased for a 12′ sidewall building. I have since been reading your posts in multiple forums regarding moment force etc., is there any mitigation that can be done with the construction that would still accommodate my original plan? Corner shear walls etc? Thank you Mr. Guru. TOM in STREETER

DEAR TOM: While shear walls (and/or bracing) can make your building shell stiffer, they do not eliminate moment (bending) loads having to be transferred through those brackets and bolt connectors. Your best bets are to either build with columns outside perimeter of existing slab, or cut out squares at each column location for either embedded columns (best design solution) or to pour wet-set brackets into piers.

Attaching Roof Purlins on Edge to Trusses

Attaching Roof Purlins on Edge to Trusses

Reader MIKE in MOUNT VERNON writes:

“If your purlins sit on top of your trusses in the middle of your building do they sit on top of the gable truss also or are they on the side of the gable truss with hangers?”

Most ‘West Coast’ (I use this liberally as it extends east into Montana and Utah) pole barn (post frame) buildings utilize a prefabricated roof truss on each side of widely spaced interior columns (most often 10’ or 12’ on center). At every roof purlin location, a short 2×6 block (known as a paddle block) is placed between these two trusses. Block length is equal to roof truss top chord thickness plus roof purlin size. With a 2×6 top chord and a 2×6 roof purlin, block length is 11 inches.

Paddle blocks are held in place by driving nails through truss top chords, into block’s narrow (1-1/2 inch) edge. Generally builders will use as many as three 20d (four inch long) nails from each side.

If your first thought was, “this is a lot of very large nails into a very small block”, you are absolutely correct. More often than not, nails will split paddle blocks, if not immediately, splits will appear over time.

Once in place, roof purlins are located uphill from the block. Purlins stagger at each truss, with first purlin attached to paddle block with two to four nails, then a second purlin is nailed to first, with nails extending into block as well.

Now, as many as 14 nails will have been placed into a single block, pretty well guaranteeing the paddle block’s inevitable failure.

Besides an obvious problem of splitting a paddle block with numerous nails, there are some other issues caused by use of these blocks.

Post frame building eave height is measured from pressure preservative treated skirt board bottom, to roofing underside at sidewall column outside. This means interior clear height, is reduced by thickness of any concrete slab, roof truss end thickness (heel height) AND (when purlins go over truss tops), roof purlin height. Having roof purlins over truss tops, costs usable space inside of building.

When using a structural design, where roof purlins overlap at each truss, roof steel cannot be pre-drilled. Pre-drilling has many benefits – perfectly straight screw lines and it makes it obvious to installers when a screw misses a roof purlin. With staggered roof purlins, all too often a leak occurs when this 1-1/2” offset at overlaps is not accounted for.

In paddle block scenarios, prefabricated roof trusses are spaced apart by 5-1/2 inches. Even though there are two trusses per column, they are not physically joined to each other. Paddle blocks are not creating a load transfer. As trusses do not load share, under extreme snow load conditions, weaker of these two trusses can fail, creating a collapse. When trusses are properly nailed together (face-to-face without paddle blocks), loads are carried by both truss pair members.

In your scenario, if (big IF) I was going to put purlins over top of interior (middle of your building) trusses, I would want to joist hang them into the side of end trusses, unless an end overhang was present.

Basic Stats for Post Frame Home Floor Plans

Basic Stats for Post Frame Home Floor Plans

If there is a single commonality among us humans it is this – we are dimensionally challenged. This situation is even more so crucial when it comes to planning your new post frame home.

Here are a few tips to help you out:


Measure from the pressure treated splash plank bottom, to intersection roofing underside at sidewall columns. This is not to be confused with ceiling height (also known as interior clear height).


For discussion’s sake (and as most post frame homes are concrete slab on grade), set a “zero point” at exterior grade (pressure treated splash plank bottom), slab top will be at +3.5 inches.

To create eight foot finished ceilings requires 8’ 1-1/8” (allows for 5/8” sheetrock on ceilings). This puts us at 8’ 4-5/8”.

Now allow for roof system thickness. With recessed (joist hung between trusses) roof purlins, 6-1/16″ for truss heel height with 2×6 top chord at 4/12 slope (provided you are using closed cell spray foam insulation between purlins).  Minimum eave height would then be 8’ 10-11/16”. If using blown-in insulation truss heel height should be insulation R value divided by 3 plus 2″ to allow plenty of eave to ridge air flow above insulation.

What about two floors?

In order to be able to run utilities (e.g. plumbing and ductwork) through second floor supports, I highly recommend 4” x 2” prefabricated wood floor trusses. Generally truss depth will be about an inch for every clear span foot with a 12 inch minimum.  Adding an arbitrarily chosen 16” deep floor truss and 8’ ceiling on second floor to example in previous paragraph puts eave height at 18’ 4-9/16”.

Stairs challenge even many experienced builders. Finished width must be no less than three feet (if planning allows, four feet is so much nicer), allow for drywall on each side when determining interior framing of stair opening width. In most jurisdictions maximum tread rise is 7-3/4” and minimum run is 10”. In above example, second floor top is 9’ 5-7/8”, so stairs would need at least 14 treads, taking up at least 140” (11’ 8”) horizontally. At stair top and bottom a space, in travel direction, equal to stair width must be provided. Headroom along every point of finished stairs must be no less than 6’8”.


Different providers measure their building footprints differently – some use wall girt outside at ‘call out’ while others use column outside and are three inches greater in width and length, this will need to be accounted for in room dimensions.

Exterior walls with bookshelf girts will be wall column thickness plus 1-1/2” for girts protruding outside of columns. With 3 or 4 ply 2×6 glulams or 6×6 columns allow 7-1/4” plus interior sheetrock thickness. Interior 2×4 walls with ½” sheetrock on each side end up 4-1/2” thick.


Below are popular post frame home rooms and their average square footage, in three categories (listed as small/medium/large):

Entry Foyer (65/89/138)
Kitchen (193/275/423)
Walk-In Kitchen Pantry (17/31/51)
Great Room (487/481/680)
Dining (148/196/281)
Living (256/319/393)
Family (311/355/503)
Recreation (216/384/540)
Entertainment/Media (140/192/280)
Master Bedroom (231/271/411)
Master Bathroom (115/144/210)
Secondary Bedrooms (130/139/178)
Other Bathrooms (93/146/313)
Laundry (67/87/145)
Utility/Mud Room (30/48/80)

Always allow adequate space for hallways (same minimum width rules apply as stairs).

Making Everything Fit Under an Attached Lean-To

Reader GEOFF in MILFORD has an often found potential challenge, he writes:

“I am looking to build a 30×40 pole barn and want to also have a covered lean to for my camper that will run the length of the barn. In order to have the lean to tall enough for the camper how tall do I need to make the peak of the barn? I need at least 11 feet of height under the roof truss to make the camper fit. My thought is that I should be able to make the barn tall enough to just extend the roof out at the same pitch to cover the lean to. But at the same time I don’t want to make the barn taller than I need to make it. 

Hope this makes sense 

Thank you”

Mike the Pole Barn Guru responds:

Yours is a frequently seen dilemma – trying to fit tall things under an attached side shed (lean to). Even worse, when a future situation arises and a shed addition is needed and main building walls were just not tall enough to make everything work comfortably and not have a very low slope shed roof.

Rather than having to make your enclosed building portion significantly taller, I would recommend you approach this with an idea of it basically being a 40 foot square building, with one sidewall ‘pulled in’ 10′. If you went with say a 13 foot eave height, you could have 12 feet of interior clear height both inside, as well as under your roof only portion. This will allow for plenty of headroom both inside (where you could have a vehicle lift) and outside for your camper. With a 4:12 roof slope your overall building height would be 19’8″ under this scenario.

Most folks would take a design approach of trying to work this as a side shed. With a 13 foot eave height on the low side of a 10 foot width shed, at the same 4:12 roof slope, your eave height of enclosed portion would need to be 16’6” making overall building height 21’6”!

Bigger Options, Taller Options, and a “Rocking” Building

This Monday the Pole Barn Guru answers reader questions about bigger options for the Charlotte 40×50 on the Home Depot site, Raymundo asks if a building can be made 2 ft. taller, and how to brace a building to stop it from “rocking” in the wind.

DEAR POLE BARN GURU: Good morning. I saw on The Home Depot® your Charlotte 40x50ft. Do you have bigger options? Could you send me the size of your biggest buildings with prices? ANTONIO in GOLDSBORO

DEAR ANTONIO: Thank you for your interest in a new Hansen Pole Building. We have an ability to provide any fully engineered post frame building with a clearspan width of 80 feet or less (100 feet in some markets – due to fabrication and shipping limitations) and up to 40 foot high walls with three stories (with sprinklers for fire suppression 50 foot and four stories). One of our Building Designers will be reaching out to you Monday for more information.


DEAR POLE BARN GURU: Hi, still really early in the planning phrase. What’s included in your kits? And can I make the barn 2ft taller? RAYMUNDO in HARTFORD

DEAR RAYMUNDO: Hansen Pole Buildings provides fully engineered, custom designed post frame buildings, with multiple buildings in all 50 states. Our buildings are designed for average physically capable person(s) who can and will read instructions to successfully construct their own beautiful buildings (and many of our clients do DIY). Our buildings come with full 24” x 36” blueprints detailing location and attachment of every piece, a 500 page fully illustrated step-by-step installation manual, as well as unlimited technical support from people who have actually built buildings. We furnish all components to seal in your building, with exceptions of concrete, rebar and nails normally driven by a nail gun.

We can provide any building up to 40 foot tall walls and three stories (or, if you add fire suppression sprinklers – 50 foot tall and four stories).

DEAR POLE BARN GURU: What bracing is used to keep the pole barn from rocking against the wind? The base is ok but the top rocks back and forth and creeks a lot. RAY in SAPULPA

Lean BuildingDEAR RAY: If your building is still under construction (in framed up stage) you should be able to stand in middle of roof and rock building back and forth by several inches, just by shifting your weight. Here is where temporary diagonal bracing of wall columns comes into play (especially if some or all of your building columns are not backfilled with pre-mix concrete.

If your building is completed, you should be reaching out to whomever provided your building’s fully engineered plans, as it sounds like there is a serious design flaw or flaws. Provided your building does not have an excess number of endwall openings (doors, windows, etc.) you can stiffen it up by replacing all of your siding and roofing screws with 1-1/2” long diaphragm screws next to each high rib, into every underlying framing member. At top and bottom of each steel panel, place screws on both sides of high ribs.

To further stiffen it, use #12 x 1-1/4” stitch screws at roughly nine inches (or less) on center through overlapping ribs of steel panels.



Working a Shop Mezzanine in With Planning Department Height Restrictions

Not every post frame building gets planned and constructed in areas where height limitations are not an issue. Reader AARON in BURLINGTON gets to deal with his Planning and Zoning Department placing height restrictions on what he can build.

Aaron writes:

Pole Barn Loft“I am planning a 45×56 pole barn, with ~16ft deep mezzanine on the end wall. The zoning rules limit the building height to 25 ft.  It seems the best options are scissor trusses with 1) 4:12 roof pitch and 2:12 ceiling pitch which puts the eave height around 16ft or 2) a 3:12 roof pitch with ~1:12 interior pitch which puts the eave height around 17.5. With a 9′ 4” Mezz Floor height and a roughly 16inch thick floor, the height under the mezz will be just under 8ft, and the min/max heights above the mezz will be roughly 1) 6 -10′ or 2) 8- 10′.  The space below will be used for vehicle storage (or possibly a pool table), and the Mezz will be used as a recreation area in the center with offices on either side wall.  The whole building will be insulated and climate controlled. 

My question is: Is it worth going to a 3:12 roof pitch in order to get the extra height on the side wall above the mezz?  Or should I stick with my preferred 4’12 pitch and accept the lower height on the sides of the mezz? Or are there other options I haven’t thought of?  Building will be in WI, where a snow cover of 6-12” is typical in the winter.”

If you research your trusses very far you are going to find you are not going to be able to get a 45′ span scissor truss with a 4:12 exterior and 2:12 interior, even spacing them every two feet (same with 3:12 and 1:12) and if you should happen to find them, they are likely to have a raised heel (reducing your interior clear height) as well as being phenomenally expensive.

Mike the Pole Barn Guru responds:

Here is my spin – and one probably no one else will suggest (in fact they are likely to raise an eyebrow over it). Stay with 4:12 exterior slope and make eave height 17’6″ to utilize every inch your Planning and Zoning friends will allow. Space sidewall columns front to rear at 14′ – 14′ – 12′ – 16′ with a pair of trusses aligned with each column and purlins joist hung on edge between trusses. With some creative truss and rear endwall column bracing, you can now utilize the space between your rear endwall and the next pair of trusses, all of the way up to the purlins! If your top of mezzanine is set at 9’4″ above grade, you will create a sloped ceiling running from roughly 7’4″ at sidewalls up to 14’10” at center, making for a spectacular recreation area (you have enough height to do lob serves playing table tennis). Make sure to have the purlins in this rear bay designed to support weight of sheetrock (as well as deflection limited to L/240 so as not to crack drywall joints). Roof of this rear 16 foot section is best insulated with 2-3″ of closed cell spray foam directly to roof steel, then the balance of the cavity filled with rock wool batts or open cell spray foam.

One last word of sage advice – do not attempt to do this on your own without an engineer having done your structural design. You will then know it is right and you will have wheels greased when you go to acquire your Building Permit.

A Future House, Eave Height, and Pricing for Horse Arena

This Monday the Pole Barn Guru answers reader questions about an ideal pole barn to convert into a house, the height of the exterior wall with an 11′ interior ceiling height, how clear span affects the costs of a horse arena.

DEAR POLE BARN GURU: Good Morning, We just put in an offer on land in Chattaroy, WA. The parcel number is 39261.0106.  Ideally, we will like to build a pole barn structure and then convert it into a house. I was wondering if you offered a service where someone could inspect the land to make sure it was buildable for this sort of structure. 

Also, do you offer a military and/or teacher discount (I work at DPMS… can’t hurt to ask, right!). We have 20 days to get the testing done. I appreciate your time and your response!
Have a great day! EMILY in CHATTAROY

DEAR EMILY: We have provided our fully engineered custom designed post frame buildings on virtually every imaginable type of building site in all 50 states. As Eastern Washington’s largest post frame building contractor in the 1990’s, my firm erected hundreds of buildings annually in Spokane County, many in Chattaroy. Unless you have a truly unusual circumstance, a post frame (pole barn) structure should be ideal for this parcel. We would recommend you have it permitted as a R-3 (residential) use structure so you do not have future challenges.

Hopefully your offer is subject to being able to pass a perc test for a future septic system, as if anything would be a stumbling point, this could be it.

Please reach out to me any time with questions.


DEAR POLE BARN GURU: If my ceiling is 11′ tall, how tall are my outside side walls to the bottom of the eve? GREG in COLUMBUS

DEAR GREG: Depending upon your building’s truss span, in most instances a 12 foot tall eave height will get you an 11 foot finished ceiling. Here is some extended reading on this subject https://www.hansenpolebuildings.com/2015/02/eave-height-2/.


DEAR POLE BARN GURU: I know the width of a pole barn has a drastic impact on price but does the increase in price go up steadily or are there certain widths that jump the price up more drastically?

I am planning to build a horse back riding arena and am deciding between the following widths: 60′ vs 66′ vs 70′ vs 72′ vs 80′

I know from 60′ to 80′ there is a huge jump in price (about $30,000 roughly based on the quotes I’ve gotten so far), but does it go up equally for each step up in size? Does being a multiple of 12′ vs 10′ make a difference? SARA in DAYTON

DEAR SARA: Our oldest daughter Bailey is a highly successful Walking Horse trainer in Shelbyville, Tennessee. She is having a new home constructed currently on acreage and had asked Dad to check out arena prices for her. I priced 60′ x 120′, 70′ x 140′ and 80′ x 160′ buildings, all with identical features. Surprisingly to me, they were all within pennies per square foot of being equal! Being as you are in a more snow sensitive area, I would suspect your pricing curve to have more of a gradual increase as spans increase from 60 feet.

In order to get some exact figures, a Hansen Pole Buildings’ Designer will be reaching out to you. Our system has an ability to adjust column and truss spacing to provide a most economical design solution at any span. Meanwhile – here is some extended reading for you https://www.hansenpolebuildings.com/2012/07/the-perfect-indoor-riding-arena/.





How Tall Should My Eave Height Be for Two Stories?

How Tall Should My Eave Height Be for Two Stories?

I have learned a couple of things in 40 years of post frame building construction. One amongst these is – most people are dimensionally challenged (no offense intended).

As much as some folks would like to believe, you cannot legitimately put two full height finished floors in a 16 foot eave height post frame building.

Now fear is a strong motivating force. Perhaps it is fear of a building “appearing” too tall or of OMG it will be too expensive keeping people from considering what it actually takes to create a Building Code conforming two story building.

Back in my early roof truss selling days, I had two clients who had relocated from New York state to North Idaho and were building new homes on adjacent properties. Both of them (and their spouses) were relatively short of stature and had decided to build their homes to Code minimum ceiling heights of seven feet. Their reasoning was it would be less space to heat and cool and they could chop two studs out of 14 foot long materials.

Missed in all of this was how much sheetrock waste would be created!

Sidebar – modern Building Codes allow seven foot ceilings under International Residential Code (IRC), however IBC (International Building Code) requires six more inches.

Now I am vertically challenged at 6’5” and would feel very uncomfortable with seven foot ceilings. In my own personal shouse, most ceilings on both floors are 16 feet high!

In today’s exciting episode we will learn together how tall eave heights should actually be to give reasonable ceilings in post frame buildings.

Setting a “zero point” at exterior grade (and assuming slab on grade for lower floor), top of slab will be at +3.5 inches.

To create eight foot finished ceilings requires 8’ 1-1/8” (allows for 5/8” sheetrock on ceilings).

In order to be able to run utilities (e.g. plumbing and ductwork) through second floor supports, I highly recommend prefabricated wood floor trusses (https://www.hansenpolebuildings.com/2020/01/floor-trusses-for-barndominiums/). Generally truss height will be about an inch for every foot of clearspan with a 12 inch minimum. 

In my own shouse, we have a 48 foot clearspan floor over our basketball court. And yes, those trusses are four feet deep!

Allow ¾ inch for OSB floor sheeting.

6-1/16″ for heel height of trusses with 2×6 top chord at 4/12 slope (provided you are using closed cell spray foam insulation between purlins)

If using blown-in insulation truss heel height should be R value of insulation divided by 3 plus 2″ to allow plenty of eave to ridge air flow above insulation.

At a bare minimum an eave height of 18’ 0-9/16” will be needed to create those eight foot ceilings.

Swinging Doors for a Post Frame Building

On Facebook I am a member of a group “Pole Barns and Buildings”. Recently a group member posted this question:

“I’m new to the group so thanks for letting me in. I’m having a 30’x48’x16′ pole barn built for a shop that will be insulated with a concrete floor. I am also putting an enclosed pull through lean-to on it for our fifth wheel with a sliding door on one end and am planning on double swinging barn doors on the other end. I can’t put a sliding door on both ends since the roll up door on the shop wouldn’t allow for the track across the front. My question is since each door is going to be 14’x7′ has anybody made swinging doors this big and what issues have you ran into? Any tips on the door construction? I’m planning on 4 12″ t hinges per door with a chain pull latch at the top, a cane bolt at the bottom and an old fashion 2×4 bar across the inside on z brackets (there is a walk through door from the shop). Sorry for the long post but I want to make sure I get this right the first time.
A disclaimer, this is NOT a Hansen Pole Building.
Our friend is actually looking to cover this open shed end with a 14 foot by 14 foot door, made of two seven foot width leaves. If I had been designing this building, I would have made some recommendations to head off this challenge before it began.
But, why not use swinging doors?
Unless they are made from a welded steel framework, it is going to be fairly difficult to eliminate sag. And (very important for most) a remote operated garage door opener is just not going to be practical.
My design suggestion would have been to construct a 44 foot width building all at 16 foot eave. This would allow for a 12 foot side by 14 foot tall overhead door instead of dealing with swinging doors. It would also eliminate a pitch break currently shown between main clearspan and shed. When all is said and done, my option would most likely have been less expensive and more practical.

Eave Height, Gambrel Size, and To Tie New to Old Building

Today the Pole Barn Guru discusses eave height, the size of a gambrel building and advice how to tie new building to existing structure.

DEAR POLE BARN GURU: When you refer to height are you measuring to the peak or sidewall? This pole barn will be used as an indoor (uninsulated) riding arena with some hay storage above. JIM in ADA

DEAR JIM: At least in our case eave height measure refers to sidewalls (https://www.hansenpolebuildings.com/2015/02/eave-height-2/).

Your expectation of being able to store hay above a riding arena is probably unrealistic, both from a standpoint of logistics and investment. Hay is very heavy and in order to carry this imposed extra weight you will multiply roof truss costs significantly. I would recommend finding a place for hay storage on ground level.

Gambrel roof pole barnDEAR POLE BARN GURU: Can you do a 48×48 gambrel style pole, 18-20 ft high? PAMELA in CASPER

DEAR PAMELA: Since my very own home is a 48 foot width post-frame gambrel building with 20 foot high sidewalls I would have to say yes. For practical purposes, we can provide virtually any low-rise building (up to three stories and 40 foot high walls). Your only limitations will be imagination, budget and available space.


DEAR POLE BARN GURU: I want to add to my metal building but the addition would require 2 valleys. How do you tie the new roof to the old on a post frame trussed roof. I have done many on a stick building. I have not been able to find any photos or steel parts for this. KURTIS in ROCKFORD

DEAR KURTIS: Your first stop (or call) should be to RDP (Registered Design Professional – architect or engineer) who provided your building’s original design. Structural changes to buildings should always be done under careful guidance of a RDP, especially when it comes to more complex roof designs where accumulations of snow could result in potential failure situations.

Most often a design solution involves removal of any overhangs where attachment will occur. A truss is then added to current sidewall face to support new addition roofline, as well as purlins on edge to create a frame over onto existing roof framing (of course roof steel on this portion of existing building needs to be removed prior to framing). Flatwise 2x framing needs to be added between existing roof purlins – we’ve normally found 2×12 centered upon newly created valley line to work well. This provides both a “landing point” for new purlins as well as backing for steel valley flashing.


Lean To or Not to Lean To?

Lean To, Or Not to Lean To?

Over my post frame building career I have seen a plethora of buildings designed with an enclosed clearspan enclosed space plus a shed roof (or lean to) for one or both sides. Most often just a roof, a lean to provides shade and not much else for whatever it covers.

But, does just a roof provide a best design solution from practicality and economic standpoints?

I suppose I have been awaiting a reader to ask this question, as my radar has seen it coming! Thanks to DAN in OREGONIA who writes:

“I want a barn 40X64 enclosed with 14’ high overhead doors in the ends i also want a 15’ lean to down one 64’ side. I am trying to maintain RV height in the lean to. Would it be more cost effective to use a 55’ span truss designed to enclose 40’ and leave the 15’ open with a ceiling as the lean to, or make the enclosed area taller to continue the pitch to 14’ at the end of the 15’ overhang? I guess that would make the building walls 19’ tall.”

Before we dive into pool’s deep end, a couple of notes in regards to this building Dan ponders. In order to have a 14 foot tall overhead door, an eave height of 16 feet (and more probably 16’6”) will be necessary. More often than not, a roof slope of 4/12 (read about roof slope here: https://www.hansenpolebuildings.com/2018/09/roof-slope/) proves most cost effective. This means across his 15 foot overhang, there will be a five foot difference in slope.

Hansen Pole RV StorageAs an alternative to a five foot elevation drop, a pitch break could be used between main clearspan and lean to roof. I usually try to avoid going steeper-to-flatter as it adds to construction complexity, adds to costs and provides a place for accumulation of debris (tree leaves and needles) as well as snow sliding off the enclosed portion.

Given a five foot difference and wanting to have RV height in the lean to, puts eave height of main portion of structure up to 21 feet or more! Certainly doable, but probably not affording many benefits unless one contemplates a mezzanine area. And while height increases are relatively affordable, they are not free by any means.

Most people view their new post frame buildings as ways to protect their valuables from not only elements, but also theft, vandalism and critters. Just a roof only partially accounts for only one of these.

In most cases, least expensive, easiest to construct and most practical design solution involves a  clearspan of entire area and placing walls around perimeter. This keeps everything securely within a space of adequate headroom – without having to increase heights just to allow for clearance within the lean to.

Considering a barn or shop with an attached lean to? Give some thought to enclosing it all with a clearspan. Affordability might prove surprising and plus you gain practicality benefits.

Garage Idea, Barn Doors, and Another Eave Height Question

Today’s blog discusses a Garage Idea, Barn Doors, and Another Eave Height Question.

DEAR POLE BARN GURU: 30’ wide x32’ deep garage 6×6 posts spaced 10’ apart except one side 16’ span. 2×8 headers doubled 2×6 side walls supporters on slab. 2×6 rafters with on 2’ centers with 2×6 connectors between rafters also on 2’ centers 1’ fall to read. Metal roof & sides. Does this sound thanks. JIM in PORT O’CONNOR

DEAR JIM: My expert opinion is you are setting yourself up for a failure – hopefully one which will not injury anyone in the collapse.

The right thing to do is to contact a post frame building kit package supplier who can provide you with not only the materials, but also the engineer sealed plans specific to your structure.


DEAR POLE BARN GURU: Can I order just steel door barn doors and tack systems from you versus an entire building? And how would I do that? And for a split door system to accommodate an opening of 10ftX5ft, what would be a rough cost estimate. Thank you. ROCKNE in PLACERVILLE

DEAR ROCKNE: Due to issues with damage in shipping, we only supply doors with the investment into a complete post frame building kit package. We suggest you visit the Pro Desk at your local The Home Depot as they should be able to assist you.


DEAR POLE BARN GURU: Is the “height” considered the peak or total height? If so, what are the exterior wall heights on an 8′ high building (for example)? Thanks in advance for your time. SHAWN




DEAR SHAWN: Post frame buildings heights are “eave” heights. Here is some reading on eave height: https://www.hansenpolebuildings.com/2015/02/eave-height-2/. An eight foot high building has an eave height of eight feet from the bottom of the pressure preservative treated splash plank to the underside of the roofing at the outside of a sidewall column.






Building Height, Building on Existing Foundation, and Spray Foam

Today the Pole Barn Guru answers questions about calculating the height of a building, Building on and existing foundation, and Spray Foam Insulation.

DEAR POLE BARN GURU: I’m looking for over all height of a building with a 14’ eave?

DEAR DOUG: The overall height determination starts with a clear understanding of how eave height is to be measured: https://www.hansenpolebuildings.com/2015/02/eave-height-2/.


With this in mind, the rise of the roof can be calculated by multiplying the distance from sidewall building line to the center of the building, in feet and multiplying this by the roof slope. Here is an example for a 36 foot width gabled roof with a 4/12 roof slope:  36′ X 1/2 (half the building width) X 4″ / 12″ = 6 feet. Adding this to the eave height gives an overall height of 20 feet, in this particular example.


DEAR POLE BARN GURU: Can they be built on a poured basement wall from a previous home? PAT in GREENEVILLE

DEAR PAT: As long as the concrete is structurally sound you should be able to utilize dry set column bases (ones designed specifically for post frame construction) to mount columns to the top of the foundation.


DEAR POLE BARN GURU: I have an existing Hansen pole barn 24×24 with a 9ft eave height and full length ridge vent, it has reflective roll insulation between the roof panels and the purlins. How can I further insulate it from Florida heat? I insulated the walls with rigid insulation. Can I add insulation under the existing reflective insulation at the roof? STEVE in ROSELAND

DEAR STEVE: I’d be contacting local installers of closed cell spray foam insulation. You will get close to R-7 per inch of foam (again, must be closed cell) and do not have the ventilation issues posed by using batt insulation between purlins. You will need to block off the eave and ridge vents for this to be an effective solution.





To Learn More, A Roof Steel Replacement, and Ideal Height

An Engineer wants to Learn More, Roof Steel Replacement, and the ideal Building Height to Accommodate an RV!

DEAR POLE BARN GURU: I’m a licensed engineer in KY. I would like to learn more about pole barn design. Do you have any references that you would recommend? James in KY

DEAR JAMES: The NFBA Post Frame Building Design manual is probably your best structural reference. https://www.hansenpolebuildings.com/2015/03/post-frame-building-3/


DEAR POLE BARN GURU: Hello. I have a Hansen building I bought in 2005 as a kit. I am planning on installing a new roof on the higher 18′ 40×35 long section. The original roof over the vaulted ceiling has leaked since day one, as the contractor did a very poor job. I’m thinking of doing a snap lock standing seam type with no exposed fasteners. To my surprise two contractors have suggested pulling the existing sheeting and replacing the standing seam( 24 ga), but no underlayment.

I thought the screwed down panels provided shear strength and rigidity to the structure.


Construction MistakeDEAR BRYAN: Indeed, standing seam steel has no shear carrying capacity, as such it should always be installed over 5/8″ or thicker CDX plywood (not OSB). However, chances are your trusses are not designed to support the added weight of the plywood. Depending upon what the exact nature of the poor installation is, the solution might be as simple as replacing offending screws with longer, larger diameter parts (if original screws were merely poorly seated). If the screws were not predrilled (therefore causing screws to either barely hit or miss roof purlins entirely), then new 29 gauge through screwed steel with properly installed screws should solve the challenges (and be phenomenally less expensive).


DEAR POLE BARN GURU: Looking to build a pole barn with 14ft height door for a RV. What would the overall height of the building be? Thanks JON in PERRYSBURG

DEAR JON: With a sliding door (not my recommendation) if your building has no endwall overhangs, then 15 foot eave height will work; with end overhangs 15’6” or 15’8” depending upon the dimension of the roof purlins.

Going to a sectional overhead door, allowing for an electric opener your eave height is most likely going to be 16’6”.

If you are planning on climate controlling the building and having a ceiling (smart choices), then the eave height will need to be further increased by the amount of roof truss heel height greater than the most common six inches.



Eave height is relatively inexpensive, don’t scrimp to try to save a few bucks and be sorry because you end up with a design solution which is less than ideal (aka a sliding door) or an overhead sectional door which will not accept an opener.

Minimum Headroom for Overhead Doors

Mike address “headroom” needs for overhead garage doors.

Reader JEFF in ROSEBURG writes: “If my roll up door opening is less than 2′ from wall height, 18″ is what I have, is there a roll up door that would work? Or is 2′ below wall height the absolute minimum?”

Mike the Pole Barn Guru writes:
Most folks use the term “roll up” door when describing overhead sectional doors. As there are very few instances where I would recommend the use of an actual roll up (coil) door, I will tailor my answers with the thought your door is actually going to be an overhead sectional door.

The real issue at hand is the amount of net clear area between the top of the concrete slab floor and the underside of the roof trusses (or roof trusses and ceiling finish if a ceiling is installed). The remaining area needs to be able to accommodate the overhead door tracks and (in most cases) allow for an electric garage door opener to be installed.

In your neck of the woods (Oregon), the vast majority of post frame (pole) buildings are constructed with a single truss mounted on each side of a sidewall column, with purlins (usually 2×6) run over the top of the trusses. With a 2×6 top chord roof truss and a fairly common 4/12 roof slope, the combination of the trusses and purlins is going to chew up 11-7/8” of space. A nominal four inch thick concrete slab is another 3-1/2” thick. After these two deductions, your 18 inches of distance from top of door opening to eave ends up being all of 2-5/8”clear.
Chances are you are in trouble and will have to reduce the height of your overhead door opening – unless…..
The door opening is in an endwall, the distance from the endwall to the first truss supporting column is three feet or more from the endwall, and the opening is far enough from a corner to avoid the door tracks from hitting the roof purlins.

Here is an example – First truss bearing columns at 12 feet from endwall, 10 foot eave height, nine foot tall overhead door (top of opening should be 9’2-1/2” above grade with a residential overhead door). This leaves all of 9-1/2” between top of door opening and eave height, however you also gain height due to the slope of the roof (less the thickness of the roof purlins). With a 4/12 roof slope and 2×6 purlins, at four feet in from the corner you now have nearly 20” of headroom! In this example it does preclude the ability to have a ceiling.
Your door opening is in a sidewall and the tracks can fit between the trusses. An example would be placing a 10’ wide overhead door centered in a 12 foot bay. Again, this only works without a ceiling.

Building height is relatively inexpensive, yet I repeatedly see cases of people trying to fit overhead doors which are too tall into buildings with eave heights which are too short. Plan in advance and just increase the eave height!

Hairpins? Best Eave Height, and the Cost of a House…

DEAR POLE BARN GURU: I am installing re-bar hairpins prepping for a pour in a Hansen pole barn. My question is about the inside poles. I have on rebar per outside pole. Do i put two rebar hairpins on the inside poles?  


DEAR ALCUIN: The purpose of the rebar hairpins is to maintain the columns in a “constrained” condition. Columns with concrete on less than all four sides would require the hairpins to keep them from separating from the slab on grade in the direction(s) away from the floor – which would cause undue deflection at grade. Interior columns which are surrounded by concrete on all sides would not require the hairpins in order to meet with the requirements of a constrained condition.



DEAR POLE BARN GURU: How tall at the eaves is needed for a pole barn so a squeeze can be used to stack hay regular hay bales? SANDRA in CORNING

DEAR SANDRA: In the end the required height is going to depend upon the equipment you own. The great majority of what I would regard as ‘serious’ at their hay storage are using eave heights of 19 to 21 feet in order to clear the trusses.

One big consideration for hay storage is preventing condensation from the underside of the roof steel. Every good hay barn should either have reflective insulation or I.C.C. (Integral Condensation Control – https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/) in the roof.

You will also get the most bang for your investment by loading from one or both eave sides, as opposed to loading from an end. In some instances, loading from the ends can work, provided there is an interior wall running across the narrow (width) direction of the barn half way between the ends.


DEAR POLE BARN GURU: I just need to know a round about price for a 2000 square foot home. Just your basic 3 bedroom 2 bath. With garage please. Thank you. STEPHANIE in STEELE

About Hansen BuildingsDEAR STEPHANIE: This is about the same as asking about how much a new car is going to cost? Do you want to drive a compact or an SUV? The possibilities of either are virtually endless.

With a post frame building being used as a home there are certain features which in my humble opinion are a must to include. Among these would be:

Built over a crawl space (https://www.hansenpolebuildings.com/2013/03/crawl-space/) – my knees just are not happy living on top of concrete.

Bookshelf style wall girts to provide a deep insulation cavity in the walls.

Use of a house wrap (https://www.hansenpolebuildings.com/2012/11/house-wrap/).

Raised heel trusses (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/).

Generally you will be looking at $15-20 per square foot for a nicely configured building shell delivered to your clear level site in the lower 48 states.

Overhead Doors and Eave Height

Putting a 14 Foot Tall Overhead Door in a Short Eave Height…

I’ve been doing post frame buildings now for a couple of years. Okay, maybe a couple of couple of years, as in 37 (ouch, am I seriously this old?). I’ve learned a certain amount of clients (and builders) are seemingly dimensionally challenged when it comes to fitting overhead doors into buildings. Quote request, after quote request has come across my desk, for the overhead door height and the building eave height to be the same!

Newer readers might want to review how eave height is measured on post frame buildings: https://www.hansenpolebuildings.com/2015/02/eave-height-2/.

Hansen Pole Buildings’ Designer Doug posed this question of me earlier today, which came from a client of his:

“Do you offer a vaulted bottom chord that would allow us to lower the sidewall height and keep 15’6” at the 14’ overhead door?”

And Doug added…..

“My instinct and experience says we need minimum 2’ especially with a 14’ high door but it never hurts to ask.” (This would be needing two feet of eave height greater than the overhead door height)

The building in question has a 40 foot wide endwall. With placement of the overhead door at the center of the endwall, here is my answer to Doug:

The bottom side of the top jamb will be at 14’2.5″ above grade, 15″ to clear = 15’5.5″. Door is 12′ wide, so allow an extra 6″ of width for the tracks. This means at 13’6″ from the sidewall, you need to have 15’5.5″ above grade. With a standard gabled roof and 2×6 top chord on the trusses, the door just fits.

If the scissor truss bottom chord was a 1/12 slope, the eave height could be lowered to 14’10.5″; 2/12 13’9″; 3/12 12’7.5″.



Now the kicker – with scissor trusses, your client had better drive straight into the building and not want to park close to one of the sidewalls, because those trusses make a nasty slapping sound when they get hit, right before the roof caves in.

Because the scissor trusses are going to require adding to the exterior slope of the building, the overall building height is going to be the same or more, and scissor trusses are more expensive than standard trusses – probably making the entire project more expensive, with less net interior clear space throughout the building.

Can he do it? Sure. Is it practical or safe? Probably not.

Calling for the Wall Steel Stretcher

Calling For The Wall Steel Stretcher

In our last episode, the dilemma of how to get a smooth roof plane was solved, to the apparent joy of all involved.

However up cropped a new challenge, contributed to by us however pretty much on the builder and this is why.

You may recall the eave height of the building was to be 16 foot and five inches.

Long time readers will recall eave height appears to be a challenge for some of the most experienced readers, so much so as it is indicated no less than five times on every set of Hansen Pole Buildings plans, as well as 51 times in the Hansen Pole Buildings Construction Manual.

For more insights into eave height please read: https://www.hansenpolebuildings.com/2015/02/eave-height-2/.

Our aforementioned Building Wizard decided to ignore the eave height markings found on multiple pages of the engineer sealed plans, and perhaps didn’t open the cover of the Construction Manual. Instead, one of our draftspersons had errantly placed a dimension on the plans for a height to the bottom of an LVL across an overhead door opening – and instead of questioning why this one single dimension did not add up to the multitude of places on the plans which had the correct dimension, he proceeded to construct the building 3 and ½ inches TOO TALL!!

Then he wondered why it was the wall steel was going to be too short!

Well, in order to prevent a major panic and cost, we came up with a solution to increase the height of the fascia by the needed difference. Here is when I got to personally fall into the trap of blunder – as I drew the correct trim on the “fix” drawing and put an incorrect part number with it. This resulted in the wrong trims being delivered to the jobsite and sending the builder off to Rantville.

And the “soffit nailer”? On the plans it is only described as the distance it is located down from the eave height – which is now 3-1/2 inches higher than the plans show. No, the distance from grade did not change, however it did move this distance down from the eave height, in order to make all of the wall steel work.

The fascia trim issue was solved by the client having some custom trims made locally, in exchange for us providing three extra sheets of roof steel to make up for the ones the builder bungled.

In the end, client gets a beautiful new building, builder gets to maintain his ego trip and happiness is maintained in post frame building land.

All’s well that ends well.

16 Foot Eave Height and Lofts

We get a few requests for quotes from clients every day – actually more like a few hundred. With this volume of inquiries, it goes to figure we see and hear a broad variety of ideas.

Buildings with loftsOne of the more popular ones is clients who want a 16 foot tall eave height and a loft (either a full or partial second floor).

When I do training sessions for our Building Designers, one of my cautions is folks are generally dimensionally challenged. This particular lofty situation being a case in point.

Most frequently eight foot high ceilings are considered a standard, and allow for two sheets of drywall to be stacked horizontally on a wall without the need to cut sheets lengthwise. The International Codes (IBC – International Building Code and IRC – International Residential Code) do allow for finished ceiling heights as low as 7’6” throughout buildings (as well as seven foot in bathrooms and kitchens), however the lower height increases the amount of work as well as waste.

So, two eight foot high ceilings add up to 16 feet, so a 16 foot eave should be ideal – right?


I’ve had some fun writing about eave height in the past, and you can too by checking out this previous article: https://www.hansenpolebuildings.com/2015/02/eave-height-2/

In our above 8 + 8 = 16 equation, there are a few things being left out. This includes:

A concrete floor – a nominal four inch thick slab on grade is going to chew up 3-1/2 inches when all is said and done;

The thickness of the roof system – as the eave height is measured to the bottom of the roofing, plan upon the loss of at least six inches of thickness to the trusses and roof purlins. If designing for a conditioned (heated and/or cooled) structure, plan upon trusses with “energy heels” https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/

These could be as deep as nearly two feet in order to allow for R-60 blown in insulation);

Oh, and last but not least, the thickness of the loft floor itself. Most folks who want loft floors would like to minimize the number of supporting columns, so planning upon the loss of a foot minimum. If the floor joists need to span much more than 20 feet (or loads greater than standard residential loads are applied), then engineered wood floor trusses come into play with a general rule of thumb being an inch of depth per foot of span.

From a practicality standpoint, the absolute minimum eave height to allow for two floors should be no less than 18’.

A Garage Door Tale

At my first business, M & W Building Supply, we provided over 6000 post frame building kit packages in the years before I turned it over to the current owner, Jim Betonte.

There were many memorable clients in those eight years, however a few instances stick in my mind.

We were contracted to supply a 30’ x 48’ building as an RV storage building and garage for a gentleman in Jefferson, Oregon. Part of why I remember it so well is the client was absolutely ecstatic about his new building – he was having a serious case of pole barn love.

He sent us several photos of his beautiful new building…..

With his RV parked in front of it…..

Because it was too tall to fit through the doors!!

Now keep in mind, this client did absolutely love his building, and he wasn’t upset with us because of his RV not fitting – after all, he was the one who picked the doors.

I was mortified.

We had not done our job well – which should have included asking just one more question of our client, “Have you actually measured the height of your RV”?

Whether your new building will house an RV or a Smart Car, I implore you to please, please, please actually measure what you are considering putting into your new building.

And consider what you might own in the future, as well as what the next owner might use the building for.

In the case of buildings meant to house RVs, it is most prudent to have a door tall enough to allow for any highway legal height vehicle to fit – which would be 14 feet. This also means an eave height of no less than 16 feet.

As a potential pole barn owner, in the event your potential building supplier doesn’t ask you specific questions in regards to heights, take the initiative yourself.

Get out your tape measure and put it to use.

Here is a case where it is so easy to expend a few minutes of effort, in exchange for years of building bliss!

Properly Done Eave Lights

See the Pretty Pole Building

Some of the time I drive my wife absolutely nuts. We are talking some serious bonkers here. A prime time for this is when I am looking at photos of newly constructed pole buildings.

She will remark, “What a nice looking building”. And then hide the photos as she realizes, even from a photo, I will find one or more things wrong with how the building was constructed.

Building Eave LightsCase in point – the building in this photo. Looks great, doesn’t it? I am sure the building will function to well meet its designed needs.

This particular sidewall features polycarbonate eave light panels – a great (and inexpensive) method to get natural light into most any pole building which will not be insulated at a later date (insulation would cover the light panels, rendering them useless).

You can read more about polycarbonate eave lights here: https://www.hansenpolebuildings.com/2011/09/polycarbonate-eavelights-light-up-my-life/

Properly done, the eave light panels should tuck up nicely against the underside of the soffit panels of the enclosed overhangs……

But wait, you say – there appears to be a line of flashing and a strip of steel above the eave lights and below the soffits!

Very astute my dear Doctor Watson.

The builder of this particular building got carried away and opted to give his client a few extra inches of headroom. Headroom which was not a part of the original plan of the building.

Loyal, long term readers of my blog have read me harping on how eave height is defined: https://www.hansenpolebuildings.com/2012/03/eave_height/

This particular builder was not properly inoculated as a child and came up with a dreaded disease: https://www.hansenpolebuildings.com/2013/04/eave-height/

His solution to the, “I built it too tall problem” resulted in the tidy little strip of steel at the top of the walls.

And, in case you are wondering, there was not supposed to be steel at all above the sliding door track covers – it should all have been eave lights!

Dear Guru: Is Toe Nailing a Good Idea?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com


DEAR POLE BARN GURU: Hello, The bottom of my 2 x 8 skirt board is about 2 inches into the ground.  Is it OK to measure 10 feet from the top of the skirt board since it is so low?

As long as the steel siding is long enough I would like to do this. If I measure from the bottom of the skirt board and add my 3  1/2  inch. of cement  then my ceiling is lower. I can add another skirt board on top of the one that is there. I can add dirt up against the outsides so it looks  OK

I hope to work on this in the morning so please answer as soon as possible.


 DEAR SITTING: You could do as you suggest (measuring the 10′ from the top of the 2×8 skirt board), as long as you add another 2×8 skirt board on top of the one you have installed, then fill up to the top of the lower 2×8 skirt board before pouring your concrete floor.

All of the steel for the siding is pre-cut to fit based upon a 0 point being the bottom of the 2×8 skirt board. There is no way to increase your interior height without ordering new wall steel or adding wainscot – either of which will prove to be a significant expense to pick up a few inches of height.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I have a pole barn that I am insulating. I am using rigid foam on ceiling between truss chords, covered with steel. Walls are 4×6 poles with 2×4 purlins on outside, sided with steel. I am adding 2×6 vertical studs on 24″ centers between poles, and stapling craft-backed roll f-glass insulation to studs, then covering wall with OSB. Should I consider stapling tar paper or other barrier to inside of purlins before adding the studs and insulation? There will be an air gap between the f-glass insulation and the outer steel, and moisture can get in via corrugations in the steel siding, top and bottom. Thanks! BUILDING IN BELLEVILLE

 DEAR BUILDING: You should place a housewrap (think Tyvek) ideally between the wall girts and the siding, but if not there, on the inside of the wall girts.

You can read more about housewrap here: https://www.hansenpolebuildings.com/blog/2012/11/house-wrap/
Here are some hints as to how to minimize the cost of your framing to support the insulation, and reduce transference of cold/heat from the contact of 2×6 vertical studs with the exterior horizontal girts.

  1. Start by placing a pressure treated 2×4 on top of the slab, flush to the inside of the columns (this board will end up between the posts, as will subsequent ones).
  2. Cut 2×4 blocks to 22-7/16″ and nail one to the each post directly above the treated 2×4.
  3. Cut a 2×4 to fit between the posts, and place like a bookshelf on top of the blocks. Repeat this process throughout the building.For best energy efficiency, make sure to completely seal the facing of the insulation batts on the inside of the wall.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: Hello, I purchased my Hansen Pole Building some time ago. I’m just now getting around to drywall, but have always been stumped with one part of the construction. How are you supposed to attach the drywall “L” top plate? (I have the commercial girt setup). There just isn’t anything to attach the top plates unless I’m toe nailing it to the posts which doesn’t seem correct to me. The girts were attached to girt blocks, but the “L” top plate doesn’t have anything like that. Like I said…this one has stumped me for some time and now that I’m getting around to drywall I need to get the top plate installed.

Thank you very much, HARRIED IN HARRISVILLE

DEAR HARRIED: The distance from center to center of your wall columns is 12’. Conservatively, the “L” supports a maximum of 12 square feet (1/2 of the distance to the first ceiling joist, which is at 24 inches on center). 5/8” gypsum wallboard weighs 2.31 pounds per square foot. This makes the weight supported by the “L” of just under 28 pounds.

The 2005 NDS® (National Design Specification® for Wood Construction published by the American Forest & Paper Association) addresses toe nailing connections in “Design Aid No. 2”. To keep the design conservative, we will use the lowest Specific Gravity value of the commonly used framing lumbers (G=0.42 for Spruce-Pine-Fir). With the specified 10d common nail (3 inch length x 0.148 inch diameter), the lateral design value for a toe-nailed connection is 83 pounds per nail.

Placing two toe-nails through each end of the vertical member of the “L” would allow the “L” to support up to 332 pounds, many times the needed design requirements.

If you are uncomfortable with toe nailing the “L”, you could cut a notch out of the top “flat” part of the “L” 1-1/2 inches deep, to fit it tightly to the face of the column above the ceiling line. Two 10d common nails could be driven through the remaining portion of the “flat” of the “L” into the column, in addition to toe nailing them.

Mike the Pole Barn Guru

How to Increase Pole Barn Clear Height

How Do I Make It Taller?

One of our clients called in earlier today as his builder is beginning construction of his new pole building kit package. He has invested in a 14’ eave height building, and while his tallest door is 10 feet high, he has now decided it may be important to have a ceiling height of 14 feet.

For the definition of eave height, read here: https://www.hansenpolebuildings.com/blog/2012/03/eave_height/

This is an issue which could have easily been headed off early on in the game, prior to the building being ordered. If a specific interior clear height is required, all it takes is expressing this as being important. With four feet of difference between door and eave heights, there really was not a red flag waived in front of his building designer to suggest interior clear height might become a concern.

Pole Barn Plans

One thing we do at Hansen Buildings is to provide an online .pdf version of each client’s building plans, prior to materials being ordered. This allows clients to confirm things like door sizes and locations, as well as heights.

Being well past these points, with materials delivered and a building crew on site, we go into what construction is truly all about – solving unforeseen challenges.

As designed and shown on the client’s plans, the interior clear height from top of slab to underside of the trusses will be roughly 13’0-7/8″.

Here were my recommendations:

There are methods of increasing the interior clear height –

While we normally do not recommend this (due to possible water issues) – the site could be excavated to place the top of the slab at grade, gaining 3-1/2″. This does necessitate having to order two 3-1/2″ longer steel panels for above the overhead door opening.

OR, an extra 2×8 Pressure Treated Skirt Board can be placed around the base of the building (stacking one above another) – gaining 7-1/4″. This does necessitate having to order two 7″ longer steel panels for above the overhead door opening. It also leaves a lot of pressure treated wood showing, which could be an aesthetic issue for some.

Both of the above could be combined to gain 10-3/4″.

Wainscot could be added around the perimeter of the building. This would necessitate having to do a lot of cutting of the existing panels, and ordering two panels above the overhead door, plus the wainscot panels, the appropriate flashings as well as more screws. While this is the most expensive option, if you absolutely must have 14′ of interior clear height, it is the best way to get you there!

The Most Asked Question by Post Frame Builders

My regular “day job” is as Technical Director for Hansen Pole Buildings. This is a fancy title for, “the guy who solves problems when things go astray”.

DIYers are frankly hilarious, as they come holding hat-in-hand saying things like, “You wouldn’t believe what I’ve done wrong, it has to be the worst mistake ever!”

In my 1990’s past life, I was a post frame contractor, running as many as 35 building crews at a given time across six Western States. To the DIYers, I let them know, “Even though I had some really great post frame builders, if a construction error could possibly be done, chances it is named after one of my crews.”

Now recently it was posed to me, “What one question do post frame builders most often ask?”

This was an easy answer, but perhaps one most would not expect, it is, “Why is my wall steel ____ (fill in the blank with amounts anywhere from 3 to 12 inches) too short?”

Usually this is quickly followed with something from a client or builder resembling, “You guys are stupid and your engineer is an idiot!”

Building Eave HeightA few years ago the ASABE (American Society of Agricultural and Biological Engineers) set out to establish a standard for uniformity in terms used in the design, construction, marketing and regulation of post frame building systems. This document, approved as an American National Standard (ANSI/ASABE S618) in January 2011, provides definitions and classifications associated with post-frame building systems.

On the surface, it would seem this standard should have kept my $64,000 question from being asked.

Here are some highlights, which would address “eave height” which ultimately could influence how long the wall steel should be:

10.11 Eave height: Vertical distance between the floor level and the eave line.”

10.2 Floor level: Elevation of the finished floor surface. In the absence of a finished floor, the floor level is taken as the elevation of the bottom edge of the bottom girt.”

NOTE: Bottom girt may also be known regionally by terms such as: Grade girt, Splash plank, Skirt board or similar.

“10.3 Eave line: Line formed by the intersection of the plane formed by the top edge of the purlins and the plane formed by the outside edge of the sidewall girts.”

Some of this is going to be open to interpretation (otherwise known as “clear as mud”). Does this mean a 14’ eave height building designed without a concrete floor, becomes a 13’8-1/2” eave height if a nominal four inch thick concrete floor is later poured using the bottom girt as a concrete form? Some post frame building kit package providers show on their plans excavating below the bottom edge of the bottom girt to allow for a future concrete floor – where is eave height then measured?

There are some who design buildings with the wall framing inset so the outside of the wall girts are in the same plane as the face of the structural columns. Others place bottom girts, wall girts and other wall framing members on the face of the columns (making the framed up building in this case three inches greater in width and length). How this 1-1/2” of framing change is accounted for can vary the length of wall steel by ½” at a 4/12 roof slope – with the difference becoming greater as the roof slope is increased.

In our case – we crafted what we felt was a clarification of how to measure eave height as, “The vertical measure from lower edge of bottom girt to intersection of underside of roofing and outside edge of sidewall columns”. I’ve counted and this description is on each of our blue prints at least seven times (across three different pages).

Last year Justine, the materials coordinator in our office, got a call from a builder who was constructing one of our building kits. The gist of the call being, “your wall steel is eight inches too short!”

Now this post frame builder did admit to having framed the building three inches taller than he should have. His reasoning – to compensate for the building having end overhangs (the thickness of the end overhang happening to be six inches). Obviously, this made far more sense to the builder, than to have followed the building plans and instructions.

Justine astutely asked him to measure the height of the building, from bottom of the pressure treated splash plank, to the top of the eave girt at the sidewall columns. Of course she knew the answer was supposed to be 14 feet, so she wasn’t overly surprised when the builder told her 14’9”!

The correct measure of eave height is shown on almost every page of the plans (along with text description of how to measure it) and also stated repeatedly in the Construction Manual provided with every purchase. Besides diagrams and photos with clear marking of dimensions, comes written encouragement for anyone not understanding eave height to call us.

In almost every case the difference to be corrected is 3-1/2” (where the builder had the idea he needed this added to compensate for the thickness of the nominal four inch thick slab), 6” (height got measured to the bottom of the truss from the bottom of the bottom girt) and 9-1/2” – when both errors are made.

As I tell DIYers and post frame builders, there is no problem which cannot be solved. This is no different.

The no cost in lumber or steel solution is to remove the bottom girt and move it up the post by the distance needing to be made up. This does result in lots of fill needing to be added to bring grade up to the bottom of the bottom girt. There is a side benefit to relocating the bottom girt, as the building is far less likely to have water pouring into it, in the event of a deluge or tremendous snow melt.

Add another wall girt directly on top of the bottom girt. If it is going to be exposed to the weather, it needs to be pressure preservative treated. This result may not be aesthetically pleasing to new building owners, however, as it leaves a great deal of treated lumber exposed.

Or, more expensive solutions, which include:

Add a piece of custom trim at the top of the wall;

Cut the wall steel off shorter and add wainscot panels;

Replace the wall steel.

Of course the best solution is to avoid the problem. Plans vary greatly from provider to provider and engineer to engineer. Rather like the “measure twice, cut once” adage, a few minutes spent perusing provided building plans and installation instructions can avoid embarrassment as well as expense.

Structural Building Design: I want….


Probably every day a client will request a specific structural feature or deviation, which is outside of what would be considered the most practical structural building design solution. These requests can range from larger poles, heavier gauge steel, to closer truss or column spacing. Today I actually had a client ask for ½” thick (not the usually requested 7/16” thickness) oriented strand board (osb) to be provided between the wall framing (girts) and the steel siding!

As building designers, the goal is always to see to it clients get the most value for their investment. This would include trying to prevent clients from throwing money at something, while gaining absolutely nothing from it.

Personally, when I get specific unusual requests, I usually try to dig to the root of the request. Asking a question such as, “Do you mind sharing with me why adding or using “X” is important to you?”  If you hear this question from me, it is only my wanting you to be a satisfied client.  I am not criticizing, just trying to figure out what the “gain” is.

When asked this question, more often than not clients will not even know why, or they will say something like, “It is because this is how everyone here builds their buildings”.

OK – time out here. I have to stop a minute and ask you, just because someone has done something 5 or 6 times, does it make it a sound thing to do? Where is the supporting documentation? I am always frustrated when I hear of clients who take our kits (which come with clear and specific plans and directions) and instead construct a building according to “the way I’ve always done it.”  They have no engineer degree.  They have no calculations to prove the connections (which is the biggest reason buildings fail, IF they fail), and worse yet, their “evidence” is, “I’ve done 5 or 6 of these over the past ten years and they haven’t fallen down yet.”!  Yikes – this is good insurance! (not) And worst of all, they are seriously upset when they run short of materials because they’ve taken a “Cadillac” kit and tried to build a “Yugo” with it, and then wonder why they run short of materials, even though they have a mountain of wrongly cut and wasted materials!

OK – back to the subject at hand. An example of how I deal with a specific case would be, “I understand your desire to have trusses every four feet, it sounds to me like your concern might be snow loads. For a lesser financial investment than placing trusses every four feet, we could increase your snow load and assure every component, not just the trusses, will support a larger load. This way, when the storm of the century does hit, you will have the last building standing”.

From a consumer standpoint, rather than becoming married early on to a particular structural building design solution, look at the end result.  The question to ask yourself is, “Will the building being proposed meet my needs and solve my problems?” There are a plethora of possible ways to construct a building, all of which will work, some of which are practical. Better yet, they have engineering proof to back them up.