Tag Archives: closed cell spray insulation

Closed Cell Spray Foam Adhesion

Closed Cell Spray Foam Adhesion to Dis-similar Materials

Reader GREG in ASHEVILLE writes:

“How long will closed cell foam maintain adhesion/air barrier function to dis-similar materials (sheet metal and lumber in the case of post frame)? I ask because my experience with foam is limited to what was sprayed beneath my floor/floor joists (estimating late 70s to early 80s). The bottom of the floor joists has a membrane to hold the foam in place. When the membrane is not present, the foam can be seen as laying on the membrane/no longer attached to the wood joists/sub-floor.

I love the concept of post framing w/ foam, seems like this saves on materials and labor needed for construction. We are currently looking to build our last/retirement house, and I believe the foam will outlast me, but when it’s time to sell will the next owner have a problem with the air sealing? 

What are your thoughts?”

Mike the Pole Barn Guru responds:

In my humble opinion, engineered post frame construction is truly an answer for material, labor and energy efficient low-rise buildings (up to three stories and 40 foot tall walls or 4 stories and 50 foot with fire suppression systems).

https://hansenpolebuildings.com/2022/01/why-your-new-barndominium-should-be-post-frame/

I have researched your adhesion concern and have been unable to find any closed cell spray foam ‘coming loose’ instance.

SPF adheres to various construction materials including metal, wood, and concrete very well. However, licensed installers must ensure surfaces are completely dry, and oils, grease, dirt, and debris free as outlined in code-referenced application standards.

It is also important to assess weather when applying spray foam. While the  product may be applied in various climatic conditions, it is important to follow manufacturer’s recommendations and its Evaluation Listing installation limitations. Sprayfoam and related coatings should not be installed when there is ice, frost, surface moisture, or visible dampness present on the surface to be covered. Surface moisture can react with SPF chemicals resulting in poor-quality foam and/or adhesion lacking.

SPF system adhesion is a key field test and licensed installers are required to conduct a field test series for adhesion and density on every project, every chemical lot change, and every eight hours. These tests are conducted using field test kits installing contractors must have on their spray rigs. Test Result must be recorded on daily worksheets and submitted to their third-party certification organization for review and retention.

In some SPF insulation installations, substrate surface priming may be required, especially when applying foam to large metal surfaces. Primers can greatly enhance adhesion between SPF and existing substrates. Primers can help seal porous substrates and improve adhesion to metal substrates.

A Barndominium Challenge

A Barndominium HVAC Challenge

My now dear friend (thanks to his barndominium) LONNIE in COLORADO SPRINGS writes:

“Hi Mike, I’m still around and still working on the house and making some slow but constant progress so I thank you all for your help and support. I have run into an issue (it’s not related to my Hansen building but I’m hoping you can offer advice anyway).. I ran into a problem getting a HVAC contractor to install my HVAC system. Not too many companies are willing to work with a owner/builder and HVAC install is way out of my wheelhouse. I was able to find a contractor that was willing to do the install but they were pretty much unwilling to do anything different than their “normal” installation (i.e. supply and return ducts in the attic). I was really wanting to do at least return air in my conditioned crawl space but they wouldn’t even consider doing that. So, in order to make progress on the project, I okayed the installation. All the building guru’s say that HVAC duct should not be placed in an unconditioned attic due to leakage and inefficiency so I’m trying to figure out how to mitigate duct losses. There are a couple of ways that I’ve thought of but I’d like your thoughts.

Options:

1: As described in some articles I’ve read and encapsulate all the ductwork with spray foam then bury all the ducts in my blown in insulation

2: Just leave the ducts as is and just bury the ducts as deep as I can afford with insulation3: I’ve thought of covering all the ducts with 6 mil plastic down to the ceiling drywall.. i.e. kind of enclose the ducts in a bubble that is attached to the ceiling, then bury it all in insulation. Covering the ducts in plastic seems like it would basically move the ducts to the conditioned space. Anyway, thank you for all your input and all the help you guys have been to me.

Thanks Lonnie”

Lonnie ~

Mike the Pole Barn Guru responds:

You are most certainly among my favorite all time clients, it has been such a pleasure working with you. While I am excited for you to be moving in, I have to admit it will be sad to not hear from you once all is completed. Since you started, one of our sons has moved to Colorado Springs, so if we get down to visit, I will drop you a message and maybe come by to see your beautiful home for real.


Your HVAC experience is why our Construction Industry in general is so far behind the curve of efficient building design – very frustrating. I would look to make those ducts as efficient as possible – I’d start with two inches of closed cell spray foam on sides and top, then bury it with enough blown in insulation to achieve an R value equal to the balance of your attic space. Closed cell spray foam will seal up any leaks in your duct work (trust me, there will be some). Return air through your crawl space would have been a no-brainer, in my humble opinion. I worked with stick frame builders nearly four decades ago who insulated their crawl space perimeters and then used those crawl spaces as one huge air return. Then, it was less expensive than running ducts.

Spray Foam Insulation and Steel Roofing and Siding

Spray Foam Insulation and Steel Roofing and Siding 

Energy efficiency is a hot (pun intended) for steel roofed and/or sided post frame buildings, especially with a rise in popularity of barndominiums and shouses. Spray foam insulation systems have been a product of choice to achieve highly efficient building envelopes.

Of course with this, have come some concerns. I recently posed a couple of questions to Dr. Richard “Rick” Duncan, P.E. Technical Director for the Spray Polyurethane Foam Alliance (SPFA).

1) Will closed cell spray foam applied to the inside of steel roofing or siding panels cause panel deterioration and/or void warranty of the panels? 2) Can closed cell spray foam be applied to a Weather Resistant Barrier successfully? If so, any special considerations?

Rick’s response:

“This issue came up about five years ago with the metal building industry.  SPFA conducted a study and the results are attached.

Closed-cell naturally shrinks as it cools and cures.  It can take about a month for the gases in the cells to come to pressure equilibrium with the atmosphere.  When applying SPF to large open areas of metal panels, the shrinkage of the foam can cause some panels to pull inward.  We call this oil canning.  

Oil canning occurs most frequently on large unsupported panels (about 4’x4’ and larger areas) and on thin gage panels with small ribs.  You find these panels mostly on ‘low-cost’ pole buildings but not on larger industrial buildings.  For these large, thin panel areas, use picture framing and apply a thin flash coat to minimize oil canning…especially on ground-level walls where oil canning can be easily seen.  Our study did not show oil canning on the heavy-duty panels used in larger commercial buildings.  

One of the concerns that the metal building industry had was exothermic temperature damage to coatings and primers used on metal panels.  A few of the metal panel manufacturers were voiding their warranties because of this concern.  Our study measured exothermic temperatures of the panel during spraying and the temperatures were below 150F, which should not affect these coatings.

Our study also looked at using different fabrics applied during construction between the sheet metal panels and the framing.  We included Tyvek WRB and non-woven ‘BIBS’ fabric.  We found that SPF does not adhere well to the more expensive Tyvek.  It does adhere to the lower-cost non-woven.  We did see that the foam would pull the non-woven fabric away from the panel by about ½” and eliminates oil-canning.  The difficulty with using non-woven fabric is that it must be applied during construction.”

From MCA (Metal Construction Association)’s technical bulletin “Spray Polyurethane Foam Insulation on Interior Surfaces of Metal Panels”:

“Closed-cell foam is recommended due to its water resistant capabilities. Some SPF contractors use a release material such as building wrap or fabric to allow for easier change out of damaged panels, however the use of a release material poses the potential of creating air gaps between the back of the SPF foam and the metal panel. These gaps could allow condensation to accumulate between the SPF and the panel and framing members.”

What Home Builders Use for Insulation

With barndominiums, shouses (shop/houses) and post frame home building on a brisk upswing, a considering factor is how to insulate new homes. Becoming as close to (or reaching) net zero (https://www.hansenpolebuildings.com/2019/01/net-zero-post-frame-homes/) as possible should be a goal of any efficient post frame home design.

Rather than me just blathering about what my opinions are, I felt of interest to share what American home builders are actually using for insulation. Keep in mind these results are from traditional stick frame construction – where a plethora of redundant wall framing members often make insulating and avoiding thermal bridges much more of a challenge than with post frame construction.

For your reading pleasure:

Originally published by the following sourceABTG Staff — August 7, 2019 

The 2019 Annual Builder Practices Survey, which had more than 1,600 homebuilder participants this year, provides some powerful insight into the thermal products market in the U.S.

According to the survey, adoption of more stringent energy codes, homebuyer demographics driving the demand for lower energy bills, labor, and building material costs are prompting homebuilders to seek higher performing insulation that is also budget-friendly. Not surprisingly, these two factors seem to be tugging the market in different directions.

The performance vs. value tradeoff in the decision to specify insulation materials continued to be a key question for most homebuilders. According to the survey, some builders would use full-cavity foam insulation, if the cost was lower. The real challenge is that some homebuilders still believe fiberglass is the best bang-for-the-buck, and if they’re looking for higher energy performance they will actually invest in things like energy efficient windows and HVAC systems over upgrading the insulation.

A builder’s insulation preference is also heavily influenced by geographic area, price-point of their homes, and how many units they build annually. For example, fiberglass batt has its deepest market penetration in Pacific states and lowest in West South Central states. Smaller builders (10 or fewer starts-per-year) are three times as likely to use spray foam than larger builders (more than 50 starts-per-year).

Source: 2019 Annual Builder Practices Survey, Home Innovation Research Labs

Difference in insulation usage was less variable when it came to home size as per building size. Yet, spray foam was about twice as likely to be used in luxury homes than starter homes, as an example. Conversely, fiberglass batts was more likely to be put in starter homes than luxury homes.

More Thoughts on Polyurethane Foam

More Thoughts on High Density Polyurethane Foam for Column Backfill

Reader STEPHEN contributes a question regarding high density polyurethane foam for column backfill:

“Hello, I have this question I would like to pass along to the “pole barn Guru” to be answered, I doubt I will get the answer I need in the time frame, but I think its going to come up more often, so  I am guessing now is a good time to ask.

With the idea of burying a 6x6x14 into concrete, the risk of Rot is very high. At a cost of about 50$ per post,  you want to protect your investment,  so many people are using a 6x6x10 and using the Study-wall brackets, but that drives up the cost to about 80$

So my question is, has anyone looked into using the new polyurethane instead of concrete?

https://www.homedepot.com/p/Secure-Set-1-Gal-Concrete-Alternative-High-Density-Polyurethane-Post-Setting-Foam-White-5-Post-Kit-SS-4-10/206497548

Stephen ~

Hopefully this response will prove to be timely in regards to your project.

Mike the Pole Barn Guru responds:

Let us begin with a discussing to overcome a fear of a “risk of rot is very high”. Actual field studies have proven an ability of properly pressure treated lumber to withstand decaying forces for greater than human lifespans: https://www.hansenpolebuildings.com/2017/12/will-poles-rot-off/. Trick, of course, is finding properly pressure preservative treated timbers. Five years ago I penned this article for a post frame industry magazine: https://www.hansenpolebuildings.com/2014/05/building-code-3/. Little has changed since then – lumber dealers and big box stores continue to sell pressure treated timbers without advising consumers as to what those timbers can actually be used for.

Now let’s discuss using high density polyurethane foam for setting columns, rather than concrete. At this year’s National Frame Building Association Expo there were several vendors promoting using their high density foam for setting posts – all of them having experience only from setting of utility poles. Utility poles carry a minimal downward load, so their holes are barely larger than column diameters, making calling for a pre-mix concrete truck impractical. Lateral loads on utility poles are also minimal as compared to columns in a post frame building, so a little high density foam easily provides a solution (and sets up quickly – allowing crews to move expediently from pole to pole).

Here is some more reading on this subject: https://www.hansenpolebuildings.com/2014/02/high-density-foam/.

Besides not being Code conforming, there is an issue of cost. Your suggested product provided at The Home Depot will provide a volume equal to five 80 pound bags of concrete (or 1/10th of a yard) for $37.63 or $376.30 per yard. With pre-mix concrete prices being roughly $100 a yard, concrete being Code conforming and not contributing to decay any more than would high density foam, it seems to me to be a no brainer.

Considering the Differences Between Closed and Open Cell Spray foam

Originally published by: Fine Homebuilding — May 21, 2016 by Mr. Rob Yagid, a former editor at Fine Homebuilding. Excerpted from Mr. Rob Yagid’s article with contributions from ABTG Staff.

The following article was produced and published by the source linked to above, who is solely responsible for its content. The Pole Barn Guru™ is publishing this story to raise awareness of information publicly available online and does not verify the accuracy of the author’s claims. As a consequence, The Pole Barn Guru™ cannot vouch for the validity of any facts, claims or opinions made in the article.

In an article by Rob Yagid for Fine Homebuilding, which was sponsored by Versi-Foam Systems, the question addressed is what is open cell versus closed cell foam? Rob delves into the debate about the properties of open-cell versus closed cell with the following points:

Much of the information you’ll find about spray foam is dedicated to its R-value and its permeability.

These traits have an overarching impact on the performance of open-cell and closed-cell foams. In most closed-cell foams, an HFC blowing agent is captured in the foam’s cell structure. This gas has a better thermal performance than the air-filled open-cell foam and gives it a higher overall R-value.However, while HFC-blown closed-cell foam might initially have an R-value as high as R-8 per in., as the blowing agent evaporates through the cell walls and is replaced by air, its R-value diminishes.

Closed-cell foam’s “aged” R-value is roughly R-6 per inch. Some manufacturers produce water-blown closed-cell foams. These foams have the same performance properties as HFC-blown foam, but slightly lower R-values at around R-5.5 per in.

Closed-cell foam’s greater density, 2 lb. per cu. ft. compared with open cell’s 1⁄2 lb. per cu. ft., also increases its R-value and offers it the rigidity that open cell foam lacks.

Structural testing, by a variety of spray foam manufacturers has confirmed that closed-cell foam increases the lateral shear and wind pressure strength of conventionally framed walls. Closed cell foam also has a low vapor permeability rating (roughly 0.5 perms at a thickness of 3 in.) and is considered a class-II vapor retarder, meaning that it’s semi impermeable.

Open-cell foam has a greater expansion rate than closed-cell foam. It expands 100 times its initial volume (closed-cell foam expands only 30 times its initial volume), so less of the foam is needed to insulate a house.

Although both foams will dry if they ever get wet, open-cell foam is vapor permeable and dries much faster than closed-cell foam.

Open cell’s one major weakness is its lower R-value, roughly R-3.5 per in. This means that when used in a 2×4 exterior wall, it will create an assembly that’s approximately only R-12, which won’t meet code in most parts of the country.

Spray polyurethane-foam manufacturers can rely upon several facts when it comes to marketing their products. According to the U.S. Department of Energy, up to 30% of a home’s heating and cooling costs are attributed to air leakage. Spray polyurethane foam is an effective air barrier and significantly reduces energy loss. Combined with a higher thermal resistance (R-value) than most other forms of insulation, it’s no wonder spray foam is often relied on to help make houses ultra-efficient. The key to proper use is knowing your climate, construction practice, wall and roof assembly types and building code requirements with a particular focus on continuous insulation. For more resources on the value of spray foam, visit continuousinsulation.org.

Help Me Insulate My Pole Building

This story is sad, to me. As post frame building “experts” we (an industry collective we) owe it to our clients to educate them at design phase to avoid a situation such as reader ERIC in SPOKANE VALLEY has become happily (or maybe less happy) involved in.

Eric writes:

“I want to start insulating my pole building. 30x40x16, roof layers are metal, synthetic underlayment, osb, 2×8 purlins. My question is, can I leave an air gap between roof and insulation, as I plan on using R19 batting and covering with facing. Has an open ridge vent. Thank you.”

Mike the Pole Barn Guru responds:

Placing batts between purlins is probably not a Top Twenty best answer for several reasons:

If you do not completely fill purlin cavities, Code requires airflow from eave to ridge over top of the insulation. You have no way to achieve this without a major remodel. You don’t even want to go there.

Getting a perfectly sealed vapor barrier under purlins would be nearly impossible to achieve.

You would have to seal the ridge vent (it isn’t working anyhow, because your building does not have an air intake from enclosed vented soffits).

While installing a flat ceiling at truss bottom chord height might appear to be a quick solution, it also is fraught with some perils:

Trusses are probably not designed to support a ceiling load. It might be possible to obtain an engineered repair from the company who produced your building’s trusses.

Ventilation system would need to be addressed for newly created dead attic space.

Closed cell spray foam insulation would need to be added in the area closest to eave sidewalls.

Weighing what you have to start with, my recommendation is to spray three inches of closed cell foam insulation below your roof sheathing. This will provide a greater R value than R19 batts and provides a vapor barrier. You will need to seal off the ridge (foam installer may be able to just spray foam underside).

Also, I notice in your photo what appears to be a total absence of truss web and bottom chord bracing. I’d have to have a copy of your building’s sealed plans, a truss drawing and some more photos to truly discern.

How Could This Have Been Avoided?

Whoever provided this post frame building should have been asking some important questions:

Will you, or anyone who might own this building in future years ever want to climate control (heat, cool or both)?

If yes, what method of roof insulation is being considered? I like insulation over a flat level ceiling personally, as I then no longer pay to heat or cool the attic area. In order to do this right, energy heels (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/) should be utilized. It also means having adequate attic insulation with soffit vents as intakes and ridge vents as exhaust.

It all could have been so much simpler.

 

Do Vapor Barriers Trap Moisture?

Vapor Barriers Trap Moisture?

Do vapor barriers trap moisture in walls of post frame buildings? They can, but only if they are installed on both sides of a wall insulation cavity.

Regular readers of this column will recognize a prevailing trend towards climate controlling both new and existing post frame buildings. An ability to control interior climate extends far beyond merely what one happens to be doing for insulation. It also includes what one does for weather resistant barriers and vapor barriers.

Insulating WallsThe purpose of a vapor barrier is to stop warm, moist, indoor air from infiltrating fiber-type insulation (think fiberglass or cellulose) during cold weather and condensing. Visible moisture or frost on the inside of a vapor barrier is either caused by a leaky vapor barrier or moisture migrating into the wall cavity from the outside. Leaky siding can cause this, and it often happens in basements that are apparently leak free. Vapor barriers are essential for any kind of insulation that air can pass through. Never do the really foolish act of slashing a vapor barrier that you find has moisture behind it or forgetting to install a vapor barrier in the first place. Today’s best vapor barriers prevent moisture from moving into wall cavities while also letting trapped moisture escape.

Recommendations below are for cold-climate construction. As a rule of thumb, if you have to heat your building more than cool it, this probably applies to your circumstance.

A weather resistant barrier (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/) will prevent moisture from entering a wall from outside of building. It also allows any moisture within a wall to exit. Pretty slick stuff, as it is smart enough to be directional.

Inside of this wall, once unfaced (recommended) insulation batts are installed, should be a vapor barrier (https://www.hansenpolebuildings.com/2017/11/vapor-barriers-post-frame-construction/). It is imperative this vapor barrier not have unsealed tears or holes. It should be sealed to floor and ceiling and any joints, rips or tears should be adequately taped. Where problems most often occur, with vapor barriers, is when penetrations are made for things such as electrical boxes. Properly sealing of these penetrations with closed cell spray foam from a can does more to prevent warm moist air to pass through into your post frame wall insulation cavity, than anything else.

 

 

 

When the Pole Building Insulation Problem is Larger Than Imagined

When the Pole Building Insulation Problem is Larger Than Imagined

From questions I have received from loyal readers over the past year, post frame (pole) building insulation is right there at the top of the list for priorities. Sadly, it seems the same concern is not often put forward by those who are designing, providing and constructing post frame buildings – leaving far too many new building owners in a world of hurt.

DISCLAIMER: This is NOT a Hansen Pole Building

Reader KEVIN in WEST CHESTER writes: “When installing my insulation do I stop just short of the vented soffit inside at the top of the wall?”

Well, this is an easy question to answer – the wall insulation needs to not cover the air intake provided from the eave vents, if the thought is for them to be used as a functional vent.

Simple, wasn’t it?

Now we can get into the challenges presented in the photo.

Unless the walls are going to be insulated with closed cell spray foam, there should be a well-sealed building wrap between the wall framing and the wall steel. This allows any moisture which would be trapped in the wall to be able to pass through to the outside world.

Now, onto the big challenge – insulating the roof.

If the idea is to have the vents in the low eave soffit be an air intake, then there needs to be a corresponding air exhaust at the high end of the shed. Along with this there needs to be the ability of unobstructed airflow from the low eave to the high side above the roof insulation. This happens to be a Building Code requirement, not to mention it is designed to prevent mold, mildew and other associated decay issues. As the roof purlins appear to be an impediment to airflow if the cavity is filled – the solution may end up being to have to use closed cell spray insulation under the roof sheathing and do away with the eave ventilation.

Moral of the story – consider insulation and ventilation needs early on in the project, in the planning stages, not after the building shell is already constructed.