Tag Archives: spray foam

A Post Frame Addition, California Muster, and Ventilation

Today the Pole Barn Guru answers questions regarding a post frame addition, passing the “muster” of California’s building codes, and ventilation of attic space with spray foam.

DEAR POLE BARN GURU: Hi. We are wanting to attach a monitor style barn to an existing stick build for additional residential use. Is this tie-in possible? Thank you! TOM in KIRTLAND

DEAR TOM: It is very possible and will quite probably provide some real advantages, besides just affordability. Post frame buildings can be any variety of sidings, so it should be able to be structurally designed to tie pretty much up to any type of exiting building – provided existing building is structurally sound.

In order to do this right you have only a couple of choices – you can spend a lot of money on an architect and/or engineer who physically comes to your site (could be as high as 20% of project’s finished costs). Or you can provide lots of information to us on what we are attaching to, as well as conveying your expectations. We will do anything reasonable to assist you in not making a mistake you will regret always. If I thought anyone else could not just actually do it but also do it better than us, with you being able to construct yourself, I would in all honesty let you know.

Please dial 1(866)200-9657 and speak with a Hansen Pole Buildings’ Designer who can assist you to success.

 

DEAR POLE BARN GURU: Hi, Do you have any residential structures that have recently passed muster in southern California?

FYI I have a lot in Malibu but little $. I am wondering if I – and usually one helper – could construct a fire resistant home in this picky building code state.

Thanks, DAN in LOS ANGELES

DEAR DAN: We’ve been providing post frame building kits in Southern California areas of Very High Fire Hazard Severity Zones as well as Wildland-Urban Interface Fire Areas for years. Is does take a certain amount of patience, as plans almost always get kicked back at least once (relax – it is just a part of this process). Using steel roofing and siding, unvented steel soffits and wrapping any wood normally exposed with steel trims expedites approvals. If your property is located in a HOA (https://www.hansenpolebuildings.com/2012/11/homeowners-association/) be certain to talk with them sooner, rather than later.

As far as you and a helper – as long as you can and will read instructions and look at our third-party engineer’s highly detailed plans you should experience no real challenges. And, if you get stuck, we provide unlimited Technical Support at no extra charge.

A Hansen Pole Buildings’ Designer will be reaching out to you for more in depth discussions.

 

DEAR POLE BARN GURU: We bought a house kit from you all and have been very pleased. We had the roof deck, exterior walls and exterior walls of the crawl space spray foam insulated. They have essentially sealed the house. Will the lack of attic ventilation be an issue? HOLLY in TAYLORSVILLE

DEAR HOLLY: Thank you for your kind words, we would enjoy seeing any digital photos or video of your building during construction as well as completed.

If you spray foamed roof deck and have a dead attic space due to a flat level ceiling (we provided ceiling loaded trusses as well as ceiling joists) then you could experience condensation issues and potentially mold and/or mildew in attic, especially if attic is not made part of conditioned space (heated and/or cooled) with living area. If flat ceiling has also been insulated look out for trouble (keep a close eye on situation by doing visual attic inspections), as attic space could become quite a bit cooler than area below ceiling. Your spray foam contractor should have been talking with you about this prior to doing his or her application.

 

Minimizing Post Frame Ice Dams

Minimizing post frame ice dams

November 1996 in Northern Idaho will probably forever be known as “Ice Storm”.  About six weeks prior to this event, my construction company had completed a post frame building just south of Sandpoint. When massive snow and ice storms hit, our client kept his new building warm by use of a wood stove. Heat from wood stove melted accumulated roof snow and ice. This snowmelt then proceeded to freeze along his building overhangs, forming ice dams.

Solid ice weighs roughly 57 psf (pounds per square foot). When our client’s roof ice buildup got to be over two feet thick, they caused a roof collapse – probably no surprise being as this weight was almost triple the building’s design roof load!

In cold climates getting a lot of snow, heat from inside a post frame building escaping into a traditional attic can warm the roof. Combine this with rooftop snow load insulating from cold exterior temperatures and roof deck can increase in temperature above freezing. When this happens, the bottom layer of snow can melt, and the resulting water will run down the roofline to roof’s edge.

If this occurs while average exterior temperatures are still below freezing, perimeter overhangs will likely be below freezing, and this liquid water can freeze near a roof’s perimeter – leading to icicles and possible ice dams.

You are probably familiar with icicles, but an ice dam occurs when a ridge of ice forms near roof edges and prevents melting snow/water from draining off the roof. Ice dams will grow as more water flows down the roof, builds up behind ice and freezes, However ice will only form when roof portions are below freezing temperatures, so as snow melts, liquid water will collect behind ice. When this water finds small cracks, crevices and openings in roofing it can flow into the building, causing damage.

Ice dams can break gutters, lift roofing and can cause water to back up and leak into pole buildings. Of course when water gets into a building, real damage occurs – wet insulation, peeling paint, warped wood, stained and sagging ceilings and more.

How do we solve ice dam problems?

A short-term fix – remove snow from the roof, such as by sweeping it off or using a “roof rake”, because no snow means no melt, so there will be no eave ice buildup. And for long-term solutions there are some mechanical options, like heat strips (https://www.hansenpolebuildings.com/2013/04/hotedge/), and there are some sound building design principles helping to lower ice dam risk.

Ice dams occur because of uneven roof deck temperatures, so the key principle in lowering ice dam risk will be to maintain more consistent roof deck temperatures. This can be done by reducing heat loss from conditioned space to attic and thereby keeping heat away from roof underside.

In practice this means reducing air leakage, increasing attic insulation value and verifying good natural roof ventilation, when applicable.

There are a couple of ways use of spray foam insulation can help mitigate ice dam risk in cold climates.

Spray foam attic floor, providing an air seal across ceiling, reducing air leakage from conditioned space to attic, and we can put in as much insulation value as desired, either with all spray foam or a hybrid system incorporating spray foam with blown in insulation above. With a vented system like this, we also want to make sure we have good natural ventilation through soffits, eaves, gables, ridges, etc. This design combines all key design principles to reduce ice damming risks.

Spray foaming underside of roof deck moves thermal boundary and air barrier to underside of roof deck. It means attic space resides inside building thermal envelope and creates a sealed, unvented attic. In this design, key plane of protection becomes spray foam layer under roof deck, protecting the roof deck from interior heat and attic air. The roof deck will now be primarily exposed to exterior conditions and more likely to remain cold.

Crawlspace Skirting, Adding Spray Foam, and Rafters

Today the Pole barn Guru discusses crawlspace skirting, adding spray foam, and building with rafters instead of trusses.

DEAR POLE BARN GURU: I am planning on building a post frame home with a standard wood framed floor structure. It will have a crawlspace below but will not have concrete stem walls. The building site slopes down, some of the crawlspace may be excavated below grade, some areas will be above grade. Looking for ideas for skirting the crawlspace to provide the most appealing look at exterior side and keep out water and pests. TRENT in WALLA WALLA

DEAR TRENT: In areas where your building’s crawl space would involve excavation below grade, it might behoove you to place a permanent wood foundation between columns (https://www.awc.org/codes-standards/publications/pwf-2015).  In other areas most of our clients have run steel siding down to four inches above grade, just like typical post frame construction.

DEAR POLE BARN GURU: Looking to spray foam the Hansen pole barn we built.

I have some questions.  We ordered the kit with roof insulation and it was installed when built. I’m thinking of leaving the ceiling open so the trusses are exposed. Can the foam be sprayed over the insulation? If the insulation is removed can the foam be sprayed directly to the roof? If so do I just close off the ridge vent? On the side walls do I just close off the top that opens to the eaves? MARK in MT. AIRY

DEAR MARK: Make sure to use only closed cell spray foam. I have heard arguments both for and against using spray foam against either a weather resistant barrier (such as Tyvek) in walls or a reflective radiant barrier. For this one I would defer to an answer from whomever will be doing your foam application, since they will have to warranty their installation. Certainly you can spray foam directly to inside of steel panels – I did this in a recent addition to my own post frame building home. You will need to close off both vented ridge as well as soffit.

DEAR POLE BARN GURU: Is it possible to build a pole building roof structure with rafters rather than trusses? FRED in GREENBANK

DEAR FRED: As long as building can have either interior columns, or single sloped (within reasonable span limits) it can certainly be raftered, rather than trussed. Please see this prior article in regards to pole and raftered buildings: https://www.hansenpolebuildings.com/2012/08/stall-barn/

 

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?
Thanks. DOUG in PILOT ROCK

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.

 

 

 

 

Spray Foam, Up Instead of Out, and a B-Ball Court

Mike answers questions about spray foam releasing agents, Going up instead of out, and a Post Frame Basketball Court.

DEAR POLE BARN GURU: Thank you for this blog of informative words on the world of post frame construction. I am a confirmed fan of spray foam insulation. What are your thoughts on the use of a release agent when applying spray foam directly to metal, be it sidewalls and a conditioned attic? CHUCK in MERINO

DEAR CHUCK: Thank you for your kind words. I’ve become a closed cell spray foam convert over the past few years. I am seeing more and more practical applications for it as folks become more energy conscious about their post frame buildings.

Spray foam release agents are a blend of specialized parting agents, specifically designed to prevent polyurethane foam insulation from adhering to most surfaces where the product is applied.

I am far from an expert on spray foam, so I’ll have to go with the common sense answer of I want the closed cell insulation to stick. I suppose it might work on sidewalls, with the idea of perhaps wanting to replace a damaged steel panel someday – provided the insulation remained rigid enough between the wall girts to stay in place. Below roof steel, I would have some concerns about the force of gravity causing it to drop off the roof. It could also lead to a gap where moisture could collect (especially if a roof leak occurs).

 

DEAR POLE BARN GURU: Curiously. I’m wanting to build post frame. I know the rule of thumb is if you have the space to build bigger on the ground before going up, but my lot is limited to only 1/4 of an acre, and strict building codes only allow so much square footage to be taken up but doesn’t go against additional levels only ground floors and basements.  So my question is: Will post frame structure support a second level, and also attic trusses for a future room later down the road? Can I even buy a kit like this? JESSE in LEESBURG

DEAR JESSE: It is always most affordable to build the largest footprint one can, on a single level. It also is most practical in terms of accessibility. Even for those who are not mobility challenged, going up and down stairs gets to be old far before we are!

You can have a post frame building designed to support both a second floor and even a third if so desired. And attic bonus trusses can be incorporated into the design. Make sure to be talking with your local Planning Department, as they often have rules which may restrict heights. The building height can also affect setbacks from property lines and other structures as well.

DEAR POLE BARN GURU: We are considering a pole barn construction for a community recreation center which would include a basketball court. We want to have second story six foot wide walking track around the interior of the building. Do you have thoughts regarding the difficulty of doing the track? BILL in ALBION

DEAR BILL: Post frame construction is most certainly the way to go for basketball courts (read more here: https://www.hansenpolebuildings.com/2017/04/indoor-basketball-courts/). Having a mezzanine walking track is most certainly doable by utilization of prefabricated metal connector plated truss frames which could be connected to the sidewall columns and cantilever over the court area below. Joists can them be placed between the frames, with ¾” thick OSB or plywood on top, then your choice of floor coverings (rubberized floor matting might be an idea).

The design should incorporate some fairly significant deflection limitations, so as not to feel bouncy to those who are utilizing the space.

The track should also be placed fairly high on the walls, so the thickness of the frames does not interfere with activities below.

 

 

 

Spray Foam Insulation: What’s the Stink?

What’s the Stink?

One popular, although expensive, method of insulating pole buildings is with spray foam insulation. Besides cost, spray foam can also bring with it problems in the form of lingering odors.  These odors are coming from a catalyst in the foam, or from foam which is off-ratio, not mixed well or sprayed too thickly.

Odors which might occur with the foam application are typically caused by either the contractor applying the foam in greater than a 2-inch pass, or applying a second pass over the first without allowing the first pass to dissipate the heat and properly cure.

The odor occurs when the foam is slightly under processed. It happens when the recommended application temperatures aren’t followed. The recommended temperature varies with the substrate and weather conditions. As an example if the recommended application temperature is 140 degrees, and spray is done at 125 degrees, a full reaction does not occur. (These are the temperatures of the product leaving the gun). In this case, the amine catalyst (which has a strong odor) does not react properly and it won’t be fully consumed. It is real stinky.

A spray foam insulation work site should be isolated with polyethylene barriers and depressurized with an exhaust fan while the foam is being sprayed.

Some believe smelly foam problems can be solved by heat and ventilating the smelly areas. Most experts advise the only way to solve these problems is to remove the bad foam from the pole building.

Even foam removal may not solve a problem with a persistent odor, however as it is thought the smell can migrate to the framing lumber.

Thinking of hiring a spray foam contractor to insulate your pole building? Find out as much as possible about their training, their certification, and their experience level. In addition to verifying the training credentials of your spray foam contractor, you should insist your contractor isolate the work area and set up a fan to depressurize the areas where foam is being sprayed.

The industry has an almost impossible problem inherent in their dependence on spray contractors who have to comply fully with all installation instructions each and every time. For instance, they may have to spray to a certain thickness, wait, and continue spraying. Contractors may or may not follow such instructions to the letter. The industry’s own guidelines call for exhaust ventilation, but this practice is widely ignored. The point is, if the spray contractors truly had to work within all manufacturer instructions and industry guidelines, it would up-price the job.

Any experienced pole building package supplier knows building materials are occasionally defective. When a damaged or defective component is on the job site, the supplier wants to be able to call up a manufacturer’s rep and have the problem resolved quickly. If this happens, the supplier becomes a loyal customer. In fact, most suppliers’ choice of door brand is based not on the door quality but on the service provided by their rep. By this standard, many spray foam insulation manufacturers are failing dismally, as the service is often less than exemplary.

The advice to spray-foam manufacturers is simple: it’s not acceptable to brush off customers with smelly foam. If these cases aren’t quickly resolved, the dead-fish smell is likely to taint the entire industry.