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Heave Ho

Heave Ho

Reader TIM in HUNTER writes:

“I have a pole building, dirt floor no concrete that has heaved up in one corner about 12 inches. I think the builder put Quick Crete in the hole of each posts. I realize it is caused by frost. The frost free hydrant located near the corner has leaked where the connection is attached to the pipe underground and this will be the third time in 20 years that I have to dig it up and have it repaired. I noticed the starting heaving about 4 or 5 years ago. My question is how to fix the issue. As no one around here in the construction business has any idea, other than a dirt contractor that thinks we can dig a channel and let the weight of the building push it back down. This comes with the challenge of deflection that could destroy all or part of the building it has heaved up about 12 inches, but there are no cracks in the rafters, stringers, or posts. See attached pictures. I really need some help in determining what to do! Pictures attached. Thank-You!”

Your dirt contractor is actually on a correct right path. This is not going to be easy, but it should preserve your building and keep issue from repeating.

At each “lifted” column, doing so one column at a time, dig down around column far enough to place a 2x6x12′ on edge (running perpendicular to wall) each side of column (centered on column) and secure with structural screws. Repeat until all lifted columns have been braced. Now, dig channel along wall at least four feet wide (need to have at least two feet on each side of exterior side of wall), extending to below current quick crete footings, and deep enough to allow building to fully be able to ‘settle’. One raised column at a time, dig an inch of soil out from under 2×6 braces. Repeat this cycle until each column has settled into an eave level position.

Next, pour new concrete footings around each previously offending column. You can use a 2′ diameter sonotube as a form (make a vertical cut in tube to allow to slip around columns), with top of tube being 22″ below bottom of splash plank.

Remove 2×6 braces.

Beyond channel, install a french drain.

Fill channel up to top of tubes with crushed gravel, compacting every six inches.

Place a 48″ wide piece of R-10 EPS or XPS rigid insulation board horizontally on top of gravel, with outside edge 2′ beyond columns.

Place another 24″ wide piece of insulation board on top of center of horizontal board and attach top to inside of splash plank. You are forming an inverted “T” with insulation boards. These insulation boards will help to keep frost from forming in ground at columns and having a repeat performance.

Carefully backfill with more crushed gravel, up to grade.

Finish grade sloping down from building six inches in 10 feet.

Install gutters, with ends of downspouts at least 10 feet from building.

This entry was posted in Pole Barn Structure, Concrete, Building Drainage, Rebuilding Structures, Columns, Pole Barn Design, Pole Barn holes, Pole Building How To Guides, Barndominium and tagged , , , , on by .

Why Are My Footings So Big?

Why Are My Footings So Big?

Reader and soon to be client CHRIS in ISANTI writes:

“Good morning, I am looking at building a pole building in the near future and have been working with Lucas on developing a plan. Question I have is why are the footings so big? It’s a 40x56x16 with a shed along the side and back gable in the future all built on sandy soil. Plan is calling out a 42” diameter and 4’ deep footing. I understand there will be a lot of weight since pole spacing is 12’. But myself and others have never heard of anything close to this large for a project like this. Did a little math on concrete and I would be looking at around $150-200 in concrete for each wet set footing. Want it built strong but not so overkill I’m wasting money. Appreciate your time in answering my question.”

Thank you for reaching out.

Here is where it all begins:

Your sandy soil will support 2000 psf. There is an allowable increase of 20% for every foot of depth or diameter over one foot.

Weight of your building plus roof loads must be able to be distributed across a footing (bottom of pier area).

Ground snow load (Pg) = 50 psf. This is converted to a flat roof snow load (Pf) by multiplying by 0.7 and 1.2 (for an unheated building).

50 psf x 0.7 x 1.2 = 42 psf

Due to you having a slippery roof (steel without a snow retention system) allows a further reduction: 42 psf x 0.938 (4/12 slope, unheated building) = 39.396 psf

You also have dead loads supported by truss chords: Top chord 5 psf (roofing and purlins) and bottom chord 10 psf (ceiling joists, ceiling and insulation)

Looking at just your basic building – 40′ span, 12″ overhangs, columns every 12′.

40’/2 (half span) x 12′ on center x (39.396 + 5 + 10) psf = 13,055.04 lbs

Overhang must be accounted for:

1′ x 12′ x (39.396 + 5) psf = 532.75 lbs

As well as weight of column (we will liberally assume weight of wall between columns is transferred to slab) 16′ glulam weighing roughly 96#

13,055.04 + 532.75 + 96 = 13,683.78 lbs

Let’s check for 4′ depth and 2′ square footing. 2000 psf x [(3 x 20%) + (1 x 20%)] = 3600 psf capacity

13,683.78 / 3600 = 3.8 sft <= 4 sft so would be good

A 2′ diameter footing would only be 3.14 sft, so would not work

Let’s assume a 12′ wide shed on 1 side (I didn’t find a width listed in your record)

12’/2 (half of shed) x 12′ x (39.396 + 5) = 3196.512 lbs

3196.512 + 13,055.04 + 96 = 16,347.552 lbs

16,347.552 / 3800 (trying 30″ square) = 4.3 sft <= 6.25 sft so 30″ square would work with plenty to spare

You could reduce amount of concrete by pouring an 8″ thick footing with sufficient area and affixing a 12″ diameter sonotube above it (we would need to know if you opt for this route so we can show on plans).

This entry was posted in Columns, Pole Barn holes, Pole Barn Questions, Barndominium, Pole Barn Planning, Footings, Budget and tagged , , , , , , on by .

A Baker’s Dozen Post Frame Home Myths Part III

A Baker’s Dozen Post-Frame Home Myths (#8 – #13)

MYTH #8. THERE ARE NO FOOTERS IN POST FRAMES

Without having footers to protect concrete slabs on grade from freezing, there is a potential your concrete slab can move or heave around edges in cold weather. In turn, this can shift interior walls, resulting in damage to drywall finishes and trim.

If you do go with post-frame construction, you will have to add footers to stay in IRC (International Residential Code) compliance. This will add cost back into your home’s total price.

Fully-engineered post frame homes are 100% Building Code Compliant and most typically have properly pressure preservative treated columns embedded in ground with both concrete footings and bottom collars. Alternatively your home can be mounted to steel brackets set in concrete piers.

Either of these are designed to extend to or below frost lines or are frost protected by use of insulation. Footers themselves do not protect a concrete slab from freezing and heaving, using rigid insulation around slab perimeters is required for either stick frame or post frame in Climate Zones 3 and greater). With fully engineered post-frame, there is no need to incorporate thickened slab edges or continuous concrete footings and foundations.

MYTH #9. POST-FRAMES WILL HAVE LARGER SPANS BETWEEN ROOF TRUSSES

This is an issue because they’ll have to be filled in before you can hang drywall. If you hang drywall “as is,” it will all sag over time, causing structural damage (and a pain in your wallet). Adding this extra framing afterwards will add to total price tag again.

While some post-frame homes do have trusses spaced every two feet, most cost effectively your fully engineered post-frame home will have double trusses every 10 to 12 feet. If you desire to insulate at ceiling lines, ceiling joists are placed every two feet to adequately support drywall. This combination of double trusses and ceiling joists will still be less expensive than conventional stick framing’s trusses every two feet with structural headers required in walls. By widely spacing trusses, it allows for greater flexibility in locating doors and windows in exterior walls.

MYTH #10. POST-FRAME HOME TRUSSES HAVE VERY LIMITED SPANS

Prefabricated metal-plate connected wood trusses can easily span 80 to 100 feet without need for interior columns. Very rarely will spans greater than these ever be needed for a post-frame home.

IRC Section 802.10.2.1 further limits truss spans for stick-frame construction to a maximum of 36 feet and building lengths to 60 feet (measured perpendicular to truss span). Fully engineered post-frame homes do not have these limitations.

MYTH #11. EXTRA FRAMING BETWEEN POSTS WILL BE NEEDED

Comment from a stick frame builder: as opposed to traditional wall building, with post-frame you’ll have to build walls between posts. This is an added cost to an already built post-frame building shell.

Chances are this builder has never built (or probably seen) a fully engineered post frame building with bookshelf girts every two feet. All exterior wall framing is taken care of at initial installation, you get a deeper insulation cavity and a better surface to drywall. 

MYTH #12. INSULATION COSTS ARE HIGHER

Your post-frame home will require more wall insulation because post-frame walls are thicker than typical two-by-four construction. Therefore, insulation cost will be higher to fill this cavity.

Proper insulation systems are an investment, not a cost. Would you really want an energy bill based off of R-13 insulation in a two-by-four exterior wall? Engineered post-frame construction allows for thicker insulation cavities – reducing your energy costs for your home’s lifespan.

MYTH #13. POST-FRAME CONSTRUCTION IS TYPICALLY NOT USED WITH BASEMENTS.

Post frame construction is not very conducive when building on a basement, as basement walls will be made from poured concrete. Trying to adapt post-frame construction to a basement will end up with higher costs than traditional home building techniques. Bottom line: If you want a home with a basement, post frame construction is not your best choice.

Fully engineered post-frame homes can easily be engineered to attach to a concrete basement foundation, ICFs or even incorporated into a Permanent Wood Foundation, at similar or lower costs than stick frame.

This entry was posted in Uncategorized, Constructing a Pole Building, Pole Barn Structure, Trusses and tagged , , , , , , , , , , , on by .

Footings, Mechanical Plans, and Hay Ventilation

This week the Pole Barn Guru answers reader questions about concrete footings for a lean-to addition, how to incorporate plumbing, electrical, and HVAC plans into to process, and proper ventilation for a hay barn.

DEAR POLE BARN GURU: We are putting a 10′ Lean-to on a Steel Framed Building. We will be using 4×6 posts spaced 10′ with 18″ holes. My question is about footings. I was hoping to tamp the bottom of the hole, add a bit of gravel, place post, add quickrete, and back fill. I am hoping to avoid filling the entire hole with concrete to save some money. If there are better ways I am open to them just looking for cost effectiveness, if possible. Thank you! PETE in UNIONVILLE

DEAR PETE: Any building is only as strong as its foundation, so this is not a place to be penny wise and pound foolish. Code requires minimum six inch thick concrete footing, or a Code approved alternative (here is an example https://www.hansenpolebuildings.com/2014/05/footingpad/).

Subject to approval from your building’s engineer, I would recommend supporting your building columns up eight inches from bottom of hole, then monopouring with concrete to give at least an 18 inch total depth of concrete. Done in this fashion, you could pour roughly 10 holes with a yard of premix. Balance of hole above this bottom collar can then be backfilled with compactible material.

 

DEAR POLE BARN GURU: When I order plans and the pole barn kit from Hansen and work as my own general contractor, how do people generally build HVAC, plumbing, electrical, etc. into the plans to take to the county to acquire permits? Do I have to get plans from those contractors and then take it to a drafter to get drawn up for approval for permits? JOHN in LAPINE

DEAR JOHN: Our floor plan team can add plumbing and electrical for a nominal fee – challenge is, your subcontractors will ignore this entirely. I have always had best results having these subcontract trades submit their own drawings when they apply for their permits (these permits are outside of your structural permit).

 

DEAR POLE BARN GURU: Have a 24ft x48ft pole barn that we store hay in. The hay is always getting moldy, hay sits on OSB wood which sits on a steel grate platform, 1ft above concrete floor. Barn roof is OSB wood with felt and shingles with a ridge vent. Sides of barn are steel with OSB wood on inside. Am thinking of building a new barn with a hay loft, but was given a suggestion to contact you first for a possible solution. Barn is in northeastern Ohio, very humid in summer. We check the hay before we store it and the moisture level is fine. I even thought of enclosing hay area and putting in a dehumidifier. Any ideas would be appreciated. Thank you, STEVE in NORTH RIDGEVILLE

DEAR STEVE: A hay barn needs proper ventilation to expel moisture from hay respiration. Hay barns are typically dependent on natural ventilation to get air exchange, so proper orientation can be critical. Typically, a hay barn should be oriented so open eave sidewalls are perpendicular to predominant wind direction.

For barns with enclosed sidewalls, enclosed vented sidewall eaves and a vented ridge are critical design elements to allow for passive ventilation. Air enters through eaves and exits through ridge vent with excess moisture.

Choose a location away from swampy areas or at bottom of a hill, as it will require more costly drainage. Gutters or rocked ditches close to sidewalls should be included in planning costs. Hay barn floor should be at least six to eight inches higher than surrounding ground level.

With a concrete slab-on-grade floor, it is crucial to have a well-sealed under slab vapor barrier.

This entry was posted in Footings, Building Interior, Pole Barn Questions, Pole Barn Design, Constructing a Pole Building, Pole Barn Planning, Ventilation, floorplans, Concrete and tagged , , , , , , , , on by .

Question About a Pole Building Under Construction

If you are like me, when you hire a professional to do professional work, you expect them to be experts and to do things correctly. Few things in life upset me more than when a builder gives a client a great price and then cuts corners in order to make a profit.

Facebooker CHRIS in TENNESSEE messaged me:

“Question about our 30×40 pole barn that is being built. Our builder set our 6×6 post straight into the ground without any type of base at the bottom and just back filled the hole with dirt. Our plans from the company show a small concrete area at the bottom of each hole but they did not do that. I wanted to reach out to you to see if you can think of any long term issues I’m going to have down the road. Just looking for some education before talking to the company. Thanks.”

Sigh…..without an adequate footing beneath columns your building is going to sink. A minimum 6″ thick concrete footing needs to be poured under every column. There should also be a provision to prevent uplift. I would recommend no further payments to them until this issue is resolved. They should be providing an engineer certified solution to this.


“They just finished the metal on the building yesterday and it dawned on me I never noticed them putting concrete in the holes. We have a security camera on the corner of the house so I pulled up the video footage and they went straight from the holes being drilled to dropping the post in. Can that even be fixed that they are this far in the build?”

It can be fixed, but it is going to take a lot of work on their part. At this point, any repair should be done only with involvement of a Registered Professional Engineer to design a fix, supply sealed drawings and to sign off on completed work as being adequate. Most important part of your building is its foundation – this is not a place to compromise. Do not get bullied into backing down, you have paid for a good building and should expect to receive one.

“I’ve been confused about how the post should be set after trying to search the Facebook group. I saw people say never use concrete that it will rot the post and cookies are useless.”

There is a lot of bad information out there and a lot of armchair engineers (including builders). Concrete does not contribute to decay of properly pressure preservative treated wood. In most cases cookies are inadequate in both thickness and diameter.

“I just got off the phone with my builder (******** Barn Company) and of course they said they build 100’s of buildings like this and don’t have an issue.”

It doesn’t matter if they have built a million this way. Unless they are willing to provide an engineer sealed drawing (specifically for your building) to confirm it is adequate – call b.s.

You are likely going to get a lot of pushback from them, as they have screwed up and this fix is going to cost them money.

“My drawings show the concrete at the base and I questioned that and I got some story that “Oh, that’s in our software by default and cannot be remove on our plans.””

8 x 12 would not have been adequate anyhow. Again – if what they have done can be verified by an engineer, then okay – reality is it cannot.

Be prepared to have to hire a Construction Attorney and whatever you do, under no circumstances pay them anything more unless this condition is resolved, or your attorney tells you it is okay to pay.

“Thank you for all the professional advice.”

This entry was posted in Pole Barn Questions, Barndominium, Constructing a Pole Building, Shouse, Building Contractor, Concrete, Concrete Cookie, Footings and tagged , , , , on by .

Yet Another Case for Engineered Buildings

Yet Another Case for Engineered Buildings

(The six photos at https://www.hudsonvalley360.com/article/construction-resumes-following-barn-collapse are essential to this story)

 

In case you are wondering why I rail so loudly about building permit agricultural exemptions for buildings, these photos (look at bases of columns) should quell any wonderment. https://www.hansenpolebuildings.com/2011/12/exempt-agricultural-buildings/

From a September 2, 2019 article by Amanda Purcell at www.thedailymail.net  of Gallatin, NY:

“Construction will resume on a farm on Green Acres Road after the barn collapsed and injured a contractor two weeks ago.

A stop-work order was issued for Red Hook-based Bijou Contracting immediately after a barn collapse injured a contractor at 138 Green Acres Road on Aug. 16, according to documents obtained from the town.

A worker suffered non-life-threatening injuries and had to be airlifted to Albany Medical Center after he became trapped under the debris, New York State Police Sgt. Michael Comerford said Aug. 16.

Emergency crews were called to the scene at 9:55 a.m. The contractor, a man, was extricated from the debris by Northern Dutchess Paramedics before firefighters arrived on the scene, Livingston Fire Department Public Information Officer Dana Petty said.

Comerford declined to identify the man or state the extent and nature of his injuries out of concern for violating the Health Insurance Portability and Accountability Act.

Building Inspector and Zoning Code Enforcement Officer Jake Exline declined to comment on the incident, investigation or what might have caused the collapse, but documents obtained via a Freedom of Information Law request showed a stop-work order was issued to Bijou Contracting the same day as the collapse.

The underlying 7,200 square-foot barn structure was mostly complete at the time of the collapse, according to photos. Photos obtained via Freedom of Information Law request show debris toppled over two scissor lifts. Photos show cement footings were released from shallow halls as a result of the collapse.

“Any and all work is to be stopped pertaining to the construction of permitted pole barn,” according to the notice signed by the zoning officer Aug. 16. “All debris is to be cleaned up and removed from the property. All construction equipment used during the construction process is to be stood back up, and removed. Once the site is clean, we can have a meeting to discuss going forward.”

The building permit was not revoked by the town, and work is expected to continue after all the materials are cleared from the site. As an agriculture building, the structure’s plans were not subject to review by the Gallatin Town Planning Board.

The building permit for the 48-foot-by-150-foot pole barn on the 89-acre farm was issued July 2 by the town to property owner Alex Fridlyard. The project was estimated to cost $70,000.”

If a picture is worth a thousand words, then those of this building’s woeful inadequate concrete piers and mounting brackets speak volumes. With an engineered building, those concrete piers would probably have been two foot or more in diameter, four feet deep (to meet frostline requirements in this area) and columns would have been mounted to engineered brackets adequate to resist imparted forces. Hopefully someone learned from this experience. However my fear is history will be sadly repeated.

Don’t let a situation like this become your mistake – for a fully engineered post frame building call us (866)200-9657

This entry was posted in Building Department, Pole Barn Structure, Building Contractor, Concrete, Rebuilding Structures, Pole Barn Design, Pole Building Comparisons and tagged , , , , , , on by .

Pre-Drilling, Housewrap, and Concrete Footings

Today the Pole Barn Guru answers reader questions about pre-drilling steel panels, the proper use of house-wrap and weather resistant barriers, as well as concern for the effectiveness or fresh concretes ability to withstand compression.

DEAR POLE BARN GURU: What size hole should I predrill in panels for the #12 diaphragm screws? Thanks! JOSEPH in KIOWA

DEAR JOSEPH: From Hansen Pole Buildings’ Construction Manual, Chapter 2:

 

“For pre-boring nail holes, 7/64” and 1/8” bits are required. Same size bit can be used for pre-drilling steel roofing and siding.”

 

DEAR POLE BARN GURU: Having read all of the info relating to insulating and am still confused. Main question is my entire 40×48 was wrapped in Tyvek including the roof. Now am trying to figure out if and how I can install a vapor barrier for the roof? Am planning to put in a ceiling with blown insulation above it and would like some options for the vapor barrier. Not sure if the roof Tyvek is a help or a hindrance. KEVIN in MALAD CITY

DEAR KEVIN: I’d like to find builders who are using Weather Resistant Barriers (WRB) under roof steel on post frame buildings, thinking they are installing a vapor barrier, and slap them silly. They have totally wasted their client’s hard earned money and, as in your case, have created a hindrance. Your only real solution is to remove Tyvek from under roof steel and replace it with an actual vapor barrier (one with a thermal break). You might see if a local spray foam installer would be willing to flash spray two inches of closed cell foam on underside of your building’s WRB.

DEAR POLE BARN GURU: My contractor poured concrete in each hole for a 30’ x 32’ pole shed and about 4 hours later started setting poles and put the entire frame up yet that same day. Can the concrete actually cure that fast or should I be concerned? PAUL in MITCHELL

DEAR PAUL: I am guessing you are talking about concrete poured for a footing pad under the columns.

Concrete gains its strength with time after casting. The rate of gain of concrete compression strength in higher during the first 28 days of casting and then it slows down. The compression strength gained by concrete after 24 hours is only 16%!

For practical purposes, a four hour old concrete footing is virtually worthless. Yes, you should be concerned.

 

This entry was posted in Roofing Materials, Concrete, Footings, Pole Barn Questions and tagged , , , , on by .

Double Skirt Boards, Siding Options, and Foundation Plans

Today’s blog discusses double skirt boards, siding options and foundation plans.

DEAR POLE BARN GURU: The pole building garage at the house I bought has two skirt boards. Can I remove the interior board to remove the dirt easier and put quikrete in its place. There is a 5” gap between the wall and the floor. The previous owner started putting quikrete in some places. Looks like the floor was put in before the building was built. KENNY in PARKERSBURG

 

 

 

DEAR KENNY: The Hansen Pole Buildings’ warehouse has the exact same situation. The interior splash plank is doing nothing for you or your building, feel free to remove it.

 

 

 

 

 

DEAR POLE BARN GURU: Can the steel exterior panels be omitted? I plan to install log siding and false log corners to match the appearance of my new log home.
Thanks BILL in WILTON

Roof Only PorchDEAR BILL: In short, yes – we can provide a building ready for you to side. What we most typically provide is 7/16” thick OSB over bookshelf girts 24 inches on center, with housewrap over the sheathing. If your false log siding can structurally provide resistance to shear, the OSB could be omitted, however this would not be my recommendation.

 

 

DEAR POLE BARN GURU: Do you include foundation plans with your kits? JOE

DEAR JOE: All Hansen Pole Buildings come with complete engineered foundation plans based upon your specific building, upon your site and reflecting the soil bearing capacity confirmed by you.

 

 

This entry was posted in Pole Barn Planning, Pole Building Siding, Footings, Alternate Siding and tagged , , , on by .

A Concrete Backfill Dilemma

Clients make for the best blog article subjects, here we have client Dan at a relative loss as to what to do about concrete backfill dilemma in and around his building columns.

DEAR POLE BARN GURU: Hi there!

 So I am about to receive everything for a 22x34x10 pole barn. The plan is to add a 4” floor after the roof is on…

 So here is my dilemma:

 The way I see it, I have a few options in installing the poles.

  1. The way you describe in the manual. 40” deep, set poles plumb, fill concrete, back fill to the grade. This requires me to probably bring in a concrete truck as I have 10 holes and hand mixing might be a pain. This is probably $500?

 

  1. A friend of mine builds barns and the guy he works with does it like this. Digs down, pours one bag of 80lb concrete and then backfills to grade. Post sets on the concrete. 

 

  1. That same friend wants his ideal barn to go like this: Dig down 36”, fill with concrete up to the level of the eventually poured floor. Each pier is the same elevation. Put a J hook in, get a post bracket and position the post on that. I did a deck this way and its nice because I have some movement. This way, I can square the bottom and tops as I put on girts. 

4.   My new way of thinking is similar to #2 but putting the posts in a post protector. This is a                 happy medium between cost and time. 

 Are any of these truly red flags? Is #4 a don’t do? Wouldn’t the posts eventually get rebar into the 4” thick floor to prevent uplifting? 

DAN in QUAKERTOWN

 DEAR DAN:  (1) Not deducting for the space occupied by the columns it would take 37 cubic feet (1.37 cubic yards) of concrete to backfill your columns. Hand mixing would be an absolute pain. You might see if your local pre-mix company could throw on a little extra concrete when they are pouring another project in the area, in order to save trucking costs.
(2) Absolutely not acceptable. There is no way 1/2 of a cubic foot of concrete becomes any sort of an adequate footing. If you are lucky it would give you a 14 inch diameter footing six inches thick. This would be close to the equivalent of just placing the column in the hole with no concrete at all! Two 80 pound bags of Sakrete could provide an adequate footing to prevent settling, but would do nothing for uplift (read lots about Sakrete for post holes here: https://www.hansenpolebuildings.com/2012/11/concrete/).
(3) The brackets your friend is talking about using are probably inadequate to carry the horizontal loads. There are brackets made specifically for the post frame industry which you could mount a column to a concrete pier (https://www.hansenpolebuildings.com/2012/09/concrete-brackets-2/). If your pre-mix company wants to charge a premium for a “short load” you could always just order more concrete and backfill the holes entirely with concrete and avoid the brackets altogether.
(4) A post protector is not going to change the inadequate footing from door number 2, however it does add the cost of the post protectors.

In my humble opinion, the only two adequate choices are #1 first, followed by #3. The rebar tie-in to the concrete slab may very well be adequate to prevent uplift forces, however we design for the worst case scenarios – where the concrete slab does not get poured immediately, or the rebar hairpins get left out.

 

Mike the Pole Barn Guru

This entry was posted in Pole Barn Questions, Pole Building How To Guides, Pole Barn Structure, Concrete, Footings and tagged , , on by .

Pole Barn or Block Foundation?

A prospective client recently posted this question about block foundations:

Barn with Rock Walls“Our family farm was started around 1850. During this time there were 12-14 barns and 1 house. Most barns deteriorated due to bad roofing. But we’re talking about stuff that lasted 100 years and some longer. We still have 4 barns left and the house which are all sitting on stacked 36″x36x12″ thick hand cut stone. My question is im getting ready to build a new building so is this type setup better than a standard pole barn? If so why does everyone then do pole barns? I could do a block foundation vs rock if this is a better way to go. The equipment building will board and batten with concrete floor and be 60×40 or so in size. Im looking for longevity and want to avoid rotting post. 

Thoughts?”

100+ years ago, a reliable pressure treating process did not exist which would preserve wood (timbers/lumber) embedded in the ground. As a result, farm buildings were constructed similar to what is described. The stone piers were probably adequate in area to prevent buildings from settling.  However they would prove no resistance to either frost heave (in areas which have frost issues), or uplift situations. If stone piers were the solution, they would be both Code conforming, as well as used extensively for new construction.

Post frame (pole buildings) have decades of reliable performance. They are the most economical permanent structure which can be built.

Although properly treated timbers will easily outlive any of us alive to read this today, there are many lumber yards selling pressure treated wood which is not designed for structural in ground use. The Building Codes require any wood which will be embedded in the ground, for foundation purposes, to be pressure preservative treated to a UC-4B (UC is Use Class) rating.

Look at the tags on the treated lumber on your next visit to a lumber yard or big box lumber provider. If the tags say UC-3 or UC-4A, they are not designed to be embedded in the ground.

Not convinced UC-4B will last? There are several manufacturers of plastic sleeves, which can be placed over the base of the columns, isolating them entirely from the surrounding soils.

Concrete footings are not inexpensive!

There are tremendous, and in my mind unnecessary, costs involved in pouring concrete footings and properly constructing either a concrete or block foundation to place a building on. There are engineered brackets which are designed to be poured into the top of foundation walls (again, beware – most post base brackets are not designed to withstand the moment loads induced into them by bending columns). Taking an educated guess, they would probably be inadequate with a block foundation, unless the block had adequate rebar and was poured solid with concrete.

Steel wins hands down for durability and longevity

If considerations include cost, being maintenance free and longevity, in my humble opinion board and batten siding is probably not the most effective design solution. I made the error of siding two of my own buildings with cedar siding, and after twenty years of having to solid body stain them – repeatedly, I would never do it again. Painted steel siding is without question going to be the most cost effective and durable design solution.

This entry was posted in Lumber, Pole Building Siding, Footings and tagged , on by .

Concrete Pier Design

A Hansen Pole Buildings client in California has just today approved the plans for his new post frame building and poses the question:

“We are in a no frost area with no snow load, so why are the concrete piers so

large and deep??”

In response:

“The column embedment (depth and diameter of the holes) has to resist several forces, including:

Resisting uplift – the columns, their encasement (the concrete attached to the base of the column) and the “cone” of soil above the concrete bottom collar, must have sufficient mass to keep the building from being literally “sucked” out of the ground.

Resisting overturning – prior to the engineering studies done over the past few decades, the “rule of thumb” was 1/3 of the column should be below grade. Modern research and technology has allowed this design to be far more scientific.

Keep the building from settling – while you state your building has no snow load, the information on your order has your building designed for a ground snow load (Pg) of 35 pounds per square foot. The concrete piers must be able to support the dead weight of the structure PLUS any live loads which would be applied to it. These live loads include the weight of any snow, or potential snow. Your building also is designed for a light storage load attic space. Any roof truss design with this type of load must be designed to support a 10 psf (pounds per square foot) dead load across the entire truss bottom chord (12,960 total pounds on your 36′ x 36′ building) by Code. The storage area adds another 20 psf for another 8640 pounds. All of these weights have to be distributed by the concrete encasement, to the soils beneath the building, with minimal settlement.”

In areas where frost is a consideration, the column encasement (footings) must also extend in depth below the frost line, in order to alleviate frost heaving.

Continuing with my response:

“Your building has been designed with a 2000 psf soil bearing capacity, which is higher than what is allowed by most California jurisdictions. The use of this number, has actually allowed for the concrete diameters of most of the holes to be far smaller than if a lower number had to be used.”

An engineered post frame building might appear to be “just another pole barn”.  They are, in reality, highly complex structures. All of the components of the building, down to the last screw or nail, are placed through an extensive series of calculations.  They must ensure adequacy against the myriad of conditions which a building must resist in order to be Code conforming. And, most importantly, to perform admirably for not only the original building owner, but also for future generations who will utilize the building.  The concrete piers are as important as the rest of the structure they support…to be designed “just right”.

This entry was posted in Concrete, Footings and tagged , , on by .
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