Tag Archives: moisture barrier

A Conventional Foundation, Weather Resistant Barrier, and Moisture Issues

Today the Pole Barn Guru answers reader questions about building a “conventional” foundation, drainage between steel and shiplap siding, and potential moisture issues of stick built vs post frame foundations.

slab edge insulationDEAR POLE BARN GURU: I am building a 24X48 pole barn, but instead of using a slab, I would like to have a conventional foundation. Is there any advice you can give me on layout and construction using this method? ROBERT in FRENCH CAMP

DEAR ROBERT: We can engineer your building to be attached to a concrete, block or ICF foundation wall using wet set brackets. As an alternative, we can also provide a pressure preservative treated Permanent Wood Foundation. Details of your choice of system will be included on your fully engineered building plans, included with your investment into one of our building kits.

 

DEAR POLE BARN GURU: I am installing pole barn metal on a shiplap sheathed chicken coop/shop. Windows framed with J-profile trim. 8-foot walls with 2-foot eaves. Panels resting on treated 2x2s. Should I worry about water drainage behind the panels? Drain holes at bottom of panels?

Thank you. HAROLD in WELCH

DEAR HAROLD: You should probably place a Weather Resistant Barrier between shiplap and steel siding. As long as you seal windows well, you should not have any issues or need drain holes at bottom of panels.

 

DEAR POLE BARN GURU: I was confused with pole verse stick built structures. I thought that I needed to pour a concrete footer to put the building on to help give me a vapor barrier. Im placing this building in a area where I get some water and I wanted to keep it 8 inch on the perimeter. If I was to use a pole built would moisture come underneath into the building. JOSHUA in EDGEWATER

DEAR JOSHUA: Having a continuous footing and foundation will not act as a vapor barrier (but will add to your expense). Building Codes require a minimum 6mil vapor barrier under any concrete slab poured in a conditioned building (and we recommend using one under any interior pour). We normally recommend using thicker material (ideally 15mil) to help prevent damage during pouring slabs on grade.

If your site is in a location where water might collect or pond, your site should be built up with good, compactable fill to a level higher than any possible water depth (and some excess wouldn’t hurt).

 

Home Addition, Combo Building, and Moisture Barriers

This week the PBG answers reader questions about a post frame addition to a house, a combo business/residential building, and use of a vapor barrier.

DEAR POLE BARN GURU: We bought an older ranch house with a poorly done addition in the back. Since this dream property came with a house that prevents me building my dream barndominium, what are your thoughts on replacing this addition with a post beam constructed addition? if we pour a slab for the floor there would be about 2 or 3 steps down to the new room. it would allow for ground level indoor/ outdoor living, higher ceilings than the rest of the ranch, and give me just a bit of the open living space with exposed trusses that I’ve dreamed of. Carolyn

DEAR CAROLYN: Fully engineered post frame additions work well with pretty much any existing structural system. You also are not obligated to use steel roofing and siding, so it can be designed to match with your home. Another advantage is – you can do this sort of work yourselves, without having to hire it done!

 

About Hansen BuildingsDEAR POLE BARN GURU: Combination business and residential? Square footage of 7000. Can it be done? KEVIN in FLORISSANT

DEAR KEVIN: Interesting timing, as I was just going through some old family photos this week and found one of my grandfather in their grocery store from the 1930’s. My mother and grandparents lived upstairs from this store.

As for modern day combination business and residential, it can certainly be done using a fully engineered post frame building. Depending upon use classification of your business, it is likely you will be required to have at least a one hour fire separation between these dissimilar uses (really not any major thing – just a consideration).

 

DEAR POLE BARN GURU: Hello, I have a 24x50x8 pole building, concrete floor, and all metal is screwed directly to the wood framing. The purlins are spaced 2′ OC between the trusses, and I have 3.5″ closed cell rigid foam board to install between the 2×4 purlins. For the walls I have 1.5″ closed cell rigid board to install between the girts.

On the underside of the purlins after the closed cell rigid insulation is installed, I intend to install metal panels from the ridge to the walls. So, outside to inside it will be the following: Roof metal, then 2×4 purlins with 3.5″ rigid closed cell foam board in between, then metal panels installed on the interior. I will not have anything on the bottom chord of the trusses.

On the walls I plan to cut-to-fit the 1.5″ closed cell rigid foam board and install between the girts. After foam board is installed I intend to line all interior walls with painted OSB.

Question: based on the above, can I use vapor barrier (or plastic) between the interior metal and the 3.5″ foam board, and extend the vapor barrier down the walls between the foam board and the OSB? Or do you have another recommendation? COREY IN COULTERVILLE

DEAR COREY: You are far more ambitious than me, to cut and fit all those insulation boards to fit between purlins and girts. As it will be impossible to perfectly seal all of those joints between insulation and framing, it would be a good idea to install a well-sealed vapor barrier between insulation boards and steel liner panels. Keep in mind, you may end up with some humidity issues inside of your building (especially if there is no vapor barrier under your concrete floor), so you may need to have some sort of mechanical dehumidification.

 

 

 

 

Insulation Addition, A Clear Span Monitor, and Post Frame Code

This week the Pole Barn Guru discusses adding insulation to an existing building, building a monitor style building with a large clear span main level, and a building official misinforming a potential client.

DEAR POLE BARN GURU: I currently have a 30×50 Wick building on some property which I purchased last May. The building is 15 years old. It had a white faced batt insulation rolled out over the roof and wall purlins. The building is heated with a 80000 btu forced air furnace and has a 3.5 ton 16 seer AC unit as well. The building is used as a mancave/shop for piddling on projects. The design has an open ceiling. I would like to add additional insulation at the roof deck level. I have a local insulation contractor who has good reviews come and look at it. He is suggesting adding a 4″ thick x 24″ wide WMP50 batt insulation between the roof purlins. The research I have done suggests to not lay a batt over a batt as you could create an area where moisture cannot pass through. If the new vapor barrier of the WMP50 is sealed correctly would there still be an issue? I’d like to keep the open ceiling design as I currently have a car lift between two of the rafters and need to be above raise the vehicle cab above the bottom of the lower rafter horizontal. This kills the idea of putting in an insulated ceiling thus creating an attic space. Any thoughts on what the contractor wants to do as well as other ideas how to better insulate the roof?

Thanks… DAVE in MARSHALL

DEAR DAVE: You want to avoid having two vapor barriers. Easiest solution would be to poke holes in your existing white facing often enough to not create any two vapor barrier zones, then add your new product, making certain all joints between rolls are sealed.

 

DEAR POLE BARN GURU: Is it possible to have a monitor style barn to use the open upper level as a living quarters and not need support legs under to keep the lower shop level open. JOE in PUEBLO

DEAR JOE: It can certainly be done, and there are a few ways to get there.

second floorHere is how we did it for my Sales Manager, Dan, in my past life when I was a post frame building contractor. Dan wanted a 30′ x 50′ monitor style building for a garage/shop and then an office above. We had engineered a clearspan roof/floor truss combination for support of wings and second floor. This system had a double truss every 10 feet. At eight feet from each outside wall, we mounted columns to these trusses to support roof of raised center. Joists we placed for ceilings and floor system. With an 8/12 roof slope, upper level used scissor trusses with a 5/12 interior pitch.

For monitor buildings without as much front to back depth, we can design with parallel chord flat trusses used as girders and bury them in knee walls of raised center portion. This often precludes ability to have windows along upper level sides.

With post frame construction, if you can dream it, chances are good we can design it.

DEAR POLE BARN GURU: Hello, I am looking at building in Chippewa County, Wisconsin. I absolutely love the idea of doing a Pole Barn House/Attached Garage. The problem is that I cannot get an answer if I can build one in the county. The building inspector has been continually telling me that they cannot be built if the garage is directly attached.

I have attached a pdf of the floor plan for said building
Can you help with this? JEFF in STANLEY

DEAR JEFF: While your pdf did not make it, there is no reason you should not be able to have an attached garage, just as you could with any other structural building system. Building Codes certainly allow for attached garages (drive through any subdivision in our country), with appropriate fire separation between it and living spaces.

If your inspector persists, please ask him or her for a written copy of whatever ordinance this advice is based upon. Chances are good there is not one, and it is based upon some personal opinion. Should documentation actually be produced, please forward to me so I can go do battle for you.

 

 

 

Gable Fan, Clay Soils, and Condensation Issues

This week the Pole Barn Guru answers reader questions about use of a gable fan to prevent condensation, building with posts in clay soils, and addressing condensation issues in a three-stall garage.

DEAR POLE BARN GURU: I have been reading some post on your site about gable vents. I have a 40×80 building with spray foam on the bottom of the roof, which is sheeted with plywood. The walls have rigid foam and fiberglass. Question is, would an electric gable fan help or hurt condensation in the building, and is it even necessary. Much of the building will become heated and cooled living space. STEVE in SOMERSET

DEAR STEVE: It is very possible a humidity controlled electric fan would assist in reducing condensation, however before moving forward with it, I would recommend you consult with your HVAC provider, as a properly designed heating and cooling system can be set up to provide adequate air exchanges and control humidity.

 

DEAR POLE BARN GURU: I have heavy clay soil that does not drain. If I put posts in ground the bottom 2 feet will be soaked most of the year. Should I use concrete piers or will proper treated post be ok? MATT in MORRISTOWN

DEAR MATT: Having personally built a post frame combination garage/shop/mother-in-law apartment at our son Jake’s then home near Maryville, I feel your pain when it comes to Tennessee clay soil. Properly pressure preservative treated columns are not negatively affected by ground water, however you have other factors to consider before moving ahead with your build. You’ll want to read these articles discussing them: https://www.hansenpolebuildings.com/2019/06/post-frame-construction-on-clay-soils/ and https://www.hansenpolebuildings.com/2020/07/barndominium-on-expansive-soils/.

 

DEAR POLE BARN GURU: Hello, We are building a 3 garage pole barn and would like to know if you suggest the following:
A. Can you spray foam insulation to house wrap and do you leave the paper under mullions if removing the paper?
B. We have sweating on our house wrap and in our bay that will be mostly finished we put insulation boards which had paper on both sides and now will have to remove that side siding to remove it.
C. Our bay 3 floor is just stone, the others are concrete. We didn’t put a vapor barrier plastic under stone, so until spring when we remove stone and do this we were thinking of laying a tarp tight on stone to hold back any moisture into the rooms for humidity and condensation. What do you suggest? LAURIE in NEW YOUR

DEAR LAURIE: While there are some installers who will spray foam to a WRB (Weather Resistant Barrier aka house wrap), we do not recommend it https://www.hansenpolebuildings.com/2020/04/spray-foam-insulation-3/

vented-closure-stripIf you are getting condensation inside of your WRB it is due to excess moisture in your building. You need to eliminate or minimize sources of water vapor (seal any concrete slabs-on-grade if a well-sealed vapor barrier was not installed beneath). Proper ventilation from eave to ridge will also help to alleviate this challenge.

Provided you can well-seal a tarp, it is certainly a better option than just leaving raw stone exposed.

 

Site Prep,

Thursday’s edition will tackle three more reader questions. First up is about how level a site must be before erecting a shop, second is about pole barn homes and the many options available, and third is a question about the best method to fix an issue left by a previous builder.

DEAR POLE BARN GURU: I am planning on building a 30’x 40’ post frame shop. The ground is dirt and has about an 8” drop from east to west. How level must the site be before erecting the shop? I will out in a concrete floor after it is built. JASON in JACKSON

DEAR JASON: Personally I would get my ground as close to level before building as possible, as it is far easier to place and properly compact fill without your building being erected. Of all things being neglected in building construction, proper site preparation and compaction probably ranks close to list tops. You will want to read my series of articles beginning here: https://www.hansenpolebuildings.com/2011/11/site-preparation/.

Photos: https://hansenpolebuildings.com/uploads/polebarnquestions/0aaae906a4e86643f513e2c2c5b99bf1.jpeg

DEAR POLE BARN GURU: I saw a few pole barn homes on your website and was wondering if that is all the plans you have?  We are interested in wood siding, not metal. TRACY

DEAR TRACY: Every post frame building Hansen Pole Buildings provides is 100% custom designed to best meet your wants and needs. We encourage our clients to design homes to best fit their lifestyle. By working from inside to out and not trying to fit what you need within a preordained box just because someone said using a “standard” site might be cheaper you can arrive at an ideal design solution. Differences in dimensions from “standard” are pennies per square foot, not dollars.

You can use the links in this article to assist with determining needed spaces, sizes and how to get expertly crafted plans and elevation drawings: https://www.hansenpolebuildings.com/2019/10/show-me-your-barndominium-plans-please/

If you find an existing plan somewhere you feel will meet your needs, we can adapt it to post frame construction and save you money. Hansen Pole Buildings can provide fully engineered post frame buildings with any type of siding or roofing materials.

 

DEAR POLE BARN GURU: I am working on finishing an apartment above a garage with framed walls/OSB and steel on the roof. The contractor who walked off the job did not put any type of vapor barrier between steel and purlins. I priced closed cell spray foam which is more than homeowner wants to pay. I was then thinking about using Visqueen on the ceiling (bottom cord of standard truss) with unfaced insulation for an airtight vapor barrier. But after more research it looks like that may not be a good option. There is ridge and soffit venting. What do you think? If not Visqueen or faced insulation do you think one inch of closed cell on the metal and batted down on the ceiling would work in Pennsylvania or would just an inch still allow sweating?

DEAR JOSHUA: Exasperating when contractors cheap out and leave clients (or client’s next builder) with a mess to have to fix.

You have only a couple of realistic options – first one is ugly, remove roof steel and place a thermal break between conditioned space and roof steel. This could be as simple as adding a Reflective Radiant Barrier. It never comes back together as well as it did originally, and when all is said and done, option number two will be less expensive.

Option two is closed cell spray foam. It really takes two inches to be an effective vapor barrier, and should run roughly two dollars per square foot of roof surface. While homeowner might not want to make this investment, he or she did not do their homework to initially be an informed buyer and if they do not solve this challenge it will be a problem forever.

 

Plans Only? Moisture Barriers? and Two Story Houses?

This week the Pole Barn Guru answers questions about “plans only” purchases, proper use of moisture barriers when adding insulation to an existing building, as well as the possibility or building a two story post frame house.

DEAR POLE BARN GURU: Do you offer just the plans? I own a sawmill and would like to mill my own lumber for my project. With the exception of the trusses. I can also source the metal roofing locally. THERON in WALDEN

Engineer sealed pole barnDEAR THERON: Thank you for your inquiry.

We are unable to provide just plans as it becomes a liability issue for our engineers – it takes away insuring materials specified actually end up being delivered to your building site.

 

There are also issues with attempting to use home milled lumber: https://www.hansenpolebuildings.com/2020/01/free-home-milled-lumber/

As an example, in sourcing your own metal roofing locally, even if steel quality was equivalent, they will not be able to provide powder coated diaphragm screws to attach it.

DEAR POLE BARN GURU: Purchased property with existing fairly new pole barn. Question is regarding wall insulation. Some installers say use double backed 6 inch glass rolls insulation under my drywall. Then I spoke with another & he says mandatory to spray closed cell foam or condition will ruin insulation…..there is no vapor barrier wrap on outside. Any help would be appreciated. Thanks, DAN in GRANBURY

DEAR DAN: You should have some sort of barrier between wall framing and wall steel to prevent condensation within the wall cavity. Wall cavity moisture can lead to a plethora of challenges – premature rusting of steel siding, rot, mold and mildew on wood framing and lack of performance of fiberglass insulation.

 

You could remove wall steel and add a Weather Resistant Barrier (highly labor intensive and things never go back together as well as they were originally assembled), or do a two inch coating of closed cell spray foam, then use fiberglass inside of it.

Here is my Ultimate Guide to Post Frame Building Insulation: https://www.hansenpolebuildings.com/2019/11/post-frame-building-insulation/

DEAR POLE BARN GURU: Hi there! I was wondering if y’all do two story residential pole houses? Second question, if I sent you guys a rough sketch of a blue print would you guys be able to give me an estimate off of that? (with included trim choices and such)

Thank you! MAX

Gambrel roof pole barnDEAR MAX: I happen to live in a two story post frame shouse (shop/house) with a partial third story. Back in the great state of Washington, I also have a three story post frame building with roof top deck! We can provide any low rise building with up to 40 foot tall walls and three floors (or 50 feet and four floors with sprinklers).

 

Send us what you have and chances are very good we can get you an estimate from it (we might want to ask you a few questions about what you intend to build).

 

Contact Information, Moisture Barrier, and Insulation

Today the Pole Barn Guru answers questions about contact information to build a structure, whether or not to use a moisture barrier in a non-conditioned attic, and guidance to insulate a post frame building.

DEAR POLE BARN GURU: Hello, I have a quick question, do you have any regional contact information for people to build these barns?  Thank you,

EARL in LOWER MICHIGAN

DEAR EARL: In many areas Hansen Pole Buildings can provide contact information of one or more possible contractors to erect buildings. We can let you know in advance if your area is one or not, however we will not provide names and numbers until after you have invested in a new post frame building kit package from us.

Why?

As much as we would like to believe otherwise, not every client or contractor is morally trustworthy. We have provided builder information to potential clients and had these same wonderful clients try to get builders to go around us and cut a better deal for their building materials. Conversely, we have had builders tell our clients to buy everything direct from them and they will get a better deal.

When either of these situations occur, clients are shortchanging themselves as they are not getting a genuine third-party engineered Hansen Pole Building. We hear about these when problems occur (they almost always do) during construction and clients call our office looking for help! My sympathy level for these people is very low, as they have gotten themselves into their own predicament – generally with disastrous results. Often times these same builders fail to see Building Permits are obtained, or neglect to call for required inspections. Or, builders will provide non-engineered and under design buildings – prone to failing under snow or wind loads far below minimum standards.

If it sounds shady, it probably is.

DEAR POLE BARN GURU: Mike, thank you for all the great info…

If I build a pole barn with attic storage and insulate only the walls and ceiling with blown in cellulose such that really only the interior ground floor space is insulated (and it will be heated in the winter), should I still worry about condensation on the roof sheet metal up in the attic, since the air up there should be at a similar temperature to outside? (There will be soffit vents and a ridge vent for attic air flow)
IE, do I need the bubble wrap material, or is it then unnecessary if the attic space is uninsulated?

Thanks! JESSE in CLEVELAND

DEAR JESSE: Thank you very much for your kind words!

Absolutely, you should be concerned about attic condensation. Warm moist air from inside your conditioned space will rise into attic and when it comes in contact with your building’s roof steel’s cooler surface it will condense (even with ventilation). For sake of ease of construction I would recommend an integrated Condensation Control Membrane (https://www.hansenpolebuildings.com/2014/07/condenstop/ ). It will be slightly more expensive for materials than a Reflective Radiant Barrier, however time saved should make it well worth your investment.

 

DEAR POLE BARN GURU: In central KY, would it be best to have outside metal, then house wrap on the girts, then plastic vapor barrier, then have blown or fiberglass insulation in the walls, then install metal interior? Is this the correct order or would this be wrong? Also on the ceiling and roof, would you put house wrap under the metal roof, then insulate directly against roof from inside, or just insulate directly on top of the ceiling, which would be metal, like the interior walls? Thank you!! BRAD in LEXINGTON

DEAR BRAD: Here is my definitive guide to post frame insulation: https://www.hansenpolebuildings.com/2018/06/pole-barn-insulation-oh-so-confusing/

In your case – you want moisture to be able to pass out of your wall cavity, so any vapor barrier needs to be on inside directly behind your finished wall surface material. House wrap (Weather Resistant Barrier or WRB) is not a vapor barrier. If installed directly under your roof steel it will allow warm moist air to pass through and you will have condensation between WRB and steel. Not good.

Directly between roof steel and purlins use one of these:

Properly sealed Radiant Reflective Barrier, Steel with Condenstop or Dripstop factory applied, 30# felt or Ice/Snow Shield over plywood or OSB, or (if none of those previously mentioned) two inches of closed cell spray foam. Me, I’d vote for Condenstop/Dripstop as it is a relatively low investment and easy to install. Blow in insulation on top of your ceiling.

And think hard about steel liner panels – they are more expensive than drywall, they reflect sound, there is a potential for condensation from your ceiling and it is difficult to attach things to walls (shelves, cabinets, work benches, etc.).

 

 

Addition to House, Stone Floor Moisture Barrier

Today the Pole Barn Guru discusses a post frame addition to a house, whether or not one should use a plastic barrier under the stone floor in a steel building, and the ability of a truss carrier to handle imposed loads.

About Hansen BuildingsDEAR POLE BARN GURU: Hi! We are considering a sizeable addition to our 600 sq ft bungalow style home, somewhere in the neighborhood of 30×40 ft addition. Wondering if it’s possible to do pole barn construction for this addition, and what kind of considerations would need to be made? The current home does have an existing basement with block foundation. I’ve read information regarding attaching a pole barn build to an existing house for use as a garage, but wondering how this scenario changes things? We would work with a licensed designer to draw up plans, and a licensed contractor for the build, but are just in the brainstorming phase at this point. KARI in WILLMAR

DEAR KARI: There are actually no real considerations for post frame not applicable to a stick frame building. You should work with a Hansen Pole Buildings designer for your building shell and we can provide engineer sealed plans for structural portions of the addition. You can work with an independent designer (FYI – there isn’t a category of licensing for designer) or create an interior layout of your own.

DEAR POLE BARN GURU: Should I put plastic down under the stone floor in a steel building? BOB in WYALUSING

DEAR BOB: It certainly would not harm anything and will help to minimize condensation issues. Look at a 15ml thickness. For more information on vapor barriers see: https://www.hansenpolebuildings.com/2017/11/vapor-barriers-slabs-grades/

 

DEAR POLE BARN GURU: Really wondering if a 2×12 SYP MSR 2400 will hold my 32ft trusses 2ft oc poles 6×6 8 oc. 1 2×12 on outside and 1 on inside. Is the 2×12 SYP MSR 2400 strong enough to hold the weight? CHRISTOPHER in CHESTERFIELD

CHRISTOPHER: In answer to your question – maybe. It will depend upon a myriad of factors including (but not limited to) Ps (roof snow load adjusted for slope), Dead loads from roofing, any roof sheathing, truss weight, any ceiling or insulation.

If you are so inclined, you can try this calculation yourself:

complex formulaLOAD (in psf – pounds per square foot) X (½ building width plus sidewall overhang in feet X 12”) X Distance spanned by beam squared (in feet)

Divide this by 8 X 2400 X 2 (for two members) X 31.6406 (Section Modulus of a 2×12) X 1.15 (Duration of Load for snow).

If your resulting answer is less than 1 then your beams will probably work.

Caveats – LOAD is Ps + all dead loads. For steel roofing over purlins 5 psf would be my recommendation. If a ceiling is to be installed a minimum of 5 psf should be added (10 psf being better).

Some important factors other than just strength include deflection (especially if trusses support a gypsum wallboard ceiling), minimum required bearing area and shear force at edge of bearing.

Frequently overlooked is connection of beams to columns. Notching in would be preferred to each face of columns.

Ultimately, RDP (Registered Design Professional – architect or engineer) who provided your sealed plans should be making a determination as to adequacy as well as providing appropriate connections.

 

Blowing Attic Insulation

Blowing Attic Insulation, Without Vapor Barrier, Below Roof Steel

A very common problem I see involves people not preparing their post frame (pole barn) buildings to adequately be insulated.

Reader NED in THURMOND writes:

“Thank you for your help. I’m in process of completing a pole barn project. It’s divided into three sections…living area, workshop, and garage. The size is 24 x 44. The outside perimeter wall is 2×6 frame with OSB and metal on the bottom and metal only in the top portion. The wall cavity is filled with unfaced insulation and poly on the inside. The roof is 8’ oc trusses with metal panels and no moisture barrier. 6 mil poly was applied to the ceiling joists. I wanted to insulate the ceiling, so I removed the poly and plan to install Sheetrock and blow in R-38 overhead. The building has a ridge vent and soffit vents in the eaves. Do I need a moisture barrier on the ceiling or will the blown in insulation suffice? What, if any problems do you anticipate? Thank you so much.”


Mike the Pole Barn Guru responds:

Here are some anticipated problems –

Without some method of condensation control beneath your building’s roof steel you are going to have moisture problems. Blown in fiberglass or cellulose insulation will lose their effective R value once they get wet. A practical solution will be to have closed cell foam insulation sprayed upon roof steel underside. Normal recommendation would be two inches thick however your local applicator(s) can give you their best input from experience. Make sure spray foam does not block either eave air intakes or ridge exhaust points. You can create a “dam” at eaves to keep blown in insulation from filling soffits, by use of ripping high R closed cell insulation boards. Again, make sure not to block incoming airflow (you need a minimum of least one inch of free area above insulation boards).

Planning a new post frame building? If so, I encourage you to take appropriate steps for your building to have future insulation installed. Yes, there will be some initial investment involved.However it will be so much less expensive to plan for it now than to wish you would have later.

 

Turf Sweating, A Post Frame Addition, and A Grow House

DEAR POLE BARN GURU: Hello, I am from Webster SD and I built a pole barn and insulated it.  I then put turf above gravel floor and use it for a indoor baseball practice facility.  It can be heated as we have heaters in there.  We have a huge problem and was wondering if you could help us solve it.  I went in there today and the humidity was 85%.  Under the turf is wet.  What is causing this and how do we solve it?  We have bats in there that are showing early signs of rust and it has been closed up for about a month.  Thanks, CHAD in WEBSTER

DEAR CHAD: The water is coming from the ground, and even makes its way up through concrete. You will need to remove the turf and then install a high quality sealed vapor barrier which is resistant to punctures or tears beneath it. In the research I have done, it appears the folks at Americover (www.americover.com) can probably make the best recommendations as to the product which will best fit your needs and budget.

Depending upon how you have insulated the building, it may also be necessary to add ventilation in order to remove excess humidity from the air.

DEAR POLE BARN GURU: Can a pole barn be mounted to a house that has a cinder block foundation? RAY in BROCKPORT

DEAR RAY: If the question is can a pole barn (post frame building) be mounted to a block foundation, as long as the foundation is adequate to carry the imposed loads, certainly. Brackets are made to either pour into a foundation, or be retrofitted to one.

If you want to attach a post frame building to a house with a cinder block foundation, the post frame building would not structurally rely upon the block. Instead, it would typically be a free standing structure abutted to the existing building and foundation.

 

 

DEAR POLE BARN GURU: Is a 28×24 pole barn with 8 foot ceiling height large enough to start a grow room? ELIZABETH in DUNDEE

DEAR ELIZABETH: It will depend upon how many plants you intend to grow. A mature plant requires four square feet of area and you need to have space to walk alongside. The eight foot high ceiling might be a bit tight as well, as some plants have the capability to grow to be as tall as a house. My best recommendation is to err on the side of caution and construct the largest footprint building which you can economically justify and which will fit within the available space.

 

 

Spray Foam Insulation with Dupont Tyvek House Wrap

Hansen Pole Buildings Designer Rachel asked me about this today:

“I have more and more builders say they put Tyvek® on the walls and roof and then spray foam.  This is so they can replace the siding/roofing in the future.  Do you find any downfalls with this?  I thought this was a pretty good idea.”

Having just written an article about spray foam insulation (https://www.hansenpolebuildings.com/2016/07/advantages-spray-foam-over-batt-insulation/), this is a well timed question.

Tyvek and all house wraps are NOT (I repeat NOT) vapor barriers. They are weather barriers: https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/.

Spray-Foam-Insulation-150x150In doing my research on the whys and why-nots I found apparently there are some spray foam insulation contractors who will not spray foam against house wraps, apparently from not being able to guarantee their product would properly adhere to the house wrap.

In one particular case – the spray foam insulation contractor tried to persuade the client to use BIBS® insulation (read about BIBS® here: https://www.hansenpolebuildings.com/2011/11/bibs/) due to the potential adhesion issues.

There apparently is an adhesive additive for spray foam, which will assist in the foam being able to stick to house wraps or other slick surfaces.

As closed cell spray foam is a vapor barrier, and is resistant to moisture passing through it in either direction, adding a weather barrier to the outside becomes redundant.

If the idea is to use a product to allow for easy residing or reroofing, then a product such as clear visqueen (https://www.hansenpolebuildings.com/2013/07/moisture-barrier/) might prove to be as effective, as well as less costly than a weather barrier. This is, of course, providing the spray foam installer is willing to spray over it.

As a good, high quality steel roofing and siding should last the life of the building – installing any product between it and the siding, under the premise of making future replacement easier, it sounds much more like someone trying to make a feature into a benefit, than it does something which will add value to the client as a benefit!