Tag Archives: closed cell spray insulation

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.