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It’s OK to Skimp On Insulation, Icynene Says

A manufacturer of open-cell spray foam advises building officials to approve insulation that doesn’t meet minimum R-value requirements

Posted on Feb 5 2010 by Martin Holladay

While energy experts often advise builders to exceed minimum code requirements for insulation, Icynene Incorporated, a manufacturer of open-cell spray polyurethane foam, is swimming against the tide. Surprisingly, Icynene is trying to convince builders to install less insulation than the code requires.

Icynene’s bizarre campaign against thick insulation is the second controversial move by the Canadian company. Last year, Icynene ruffled energy experts’ feathers by waging a spirited (and successful) lobbying campaign to defeat a widely supported effort (the so-called “Thirty Percent Solution”) to raise the stringency of insulation requirements in the International Residential Code.

The motive for Icynene’s current effort — let’s call it the “it’s OK to skimp” campaign — appears to be economic. The company has apparently decided that the only way Icynene can compete with less-expensive types of insulation (like cellulose) is to convince builders that they can get away with less insulation than code books require.

Air sealing requirements in the code
There’s no way to fathom Icynene’s tangled logic without first taking a look at existing code requirements for sealing air leaks.

In the 2006 International Residential Code (IRC), air-sealing requirements can be found in section N1102.4. The code requires that “The building thermal envelope shall be durably sealed to limit infiltration. …The following shall be caulked, gasketed, weatherstripped, or otherwise sealed with an air barrier material, suitable film, or solid material:
1. All joints, seams and penetrations.
2. Site-built windows, doors and skylights.
3. Openings between window and door assemblies and their respective jambs and framing.
4. Utility penetrations.
5. Dropped ceilings or chases adjacent to the thermal envelope.
6. Knee walls.
7. Walls and ceilings separating the garage from conditioned spaces.
8. Behind tubs and showers on exterior walls.
9. Common walls between dwelling units.
10. Other sources of infiltration.”

The real zinger in this list is #10: “Other sources of infiltration.” That just about covers it, doesn’t it?

The IRC requires all sources of infiltration to be “caulked, gasketed, weatherstripped, or otherwise sealed with an air barrier material, suitable film, or solid material.” The code does not include any exceptions. In other words, there is no such thing as a legal crack or air leak.

Building inspectors rarely check airtightness
Unfortunately, the requirements of Section N1102.4 are rarely enforced, and as a result, many new American homes — especially fiberglass-insulated homes — perform poorly.

Icynene has seized on this fact — the fact that lax code enforcement has encouraged the proliferation of leaky homes — to put forth the surprising proposition that Icynene-insulated homes can perform poorly, too.

To match the poor performance of leaky fiberglass-insulated homes, all an Icynene contractor has to do is skimp on insulation thickness.

The code says R-38, but what the heck — R-20 should work
As an example of Icynene’s tactics, consider the experience of Sophie Piesse, an architect in Carrboro, North Carolina. Piesse was advised by a spray-foam contractor to insulate a cathedral ceiling with only 5 1/2 in. of open-cell spray foam (equivalent to about R-20). Since the local prescriptive code (the North Carolina State Building Code) requires ceilings to be insulated to a minimum of R-38, the contractor’s recommendation was surprising.

When Piesse questioned the contractor further, she was presented with a letter from Icynene that justifies installing only 52% of the minimum insulation thickness required by code. Presumably, the letter is intended to convince a local code official that Icynene is so good that there’s nothing wrong with skimping on R-value.

Signed by Viktor Ginic, a building science engineer at Icynene, the letter reads, “The air-seal advantage of Icynene provides improved energy performance over much higher R-value insulations that are air-permeable. The blower-door testing of airtightness of the houses insulated with Icynene indicates an average air infiltration rate 5.5 times lower than a house insulated with mineral fiber insulation. Based on measured air infiltration and the number of energy analyses performed, we have found that Icynene, installed in accordance with the manufacturer’s installation instructions to a nominal thickness of 3" in the walls and floors and 6" in roof/ceiling applications will perform better thermally than R-19 and R-38 air-permeable mineral fiber insulation.” [Author's note: since this blog was written, two sources have confirmed that Viktor Ginic's letter specifically applies to builders complying with performance paths of code compliance, not prescriptive paths.]

Unscrambling Icynene’s logic
The prescriptive path of the IRC clearly requires a home to comply with two separate requirements:

  • It must meet minimum insulation requirements, and
  • It must be sealed against air leakage.

By arguing in favor of cutting corners on insulation thickness, here’s what Icynene appears to be saying: “We’ve noticed that most building inspectors aren’t enforcing air-sealing requirements. That gives us an idea! If some houses are violating one part of the building code, why not let us violate a different part of the code? Many fiberglass-insulated houses don’t meet air-sealing requirements — so we think it’s only fair that Icynene-insulated houses be allowed to cut corners when it comes to minimum insulation requirements.”

That’s right — the company is arguing, “An Icynene-insulated house with an R-20 ceiling is at least as good as that illegal house down the street.” Talk about bragging rights!

When I called Icynene to inquire about the company’s startling advice, I was connected with Ed Reeves, Icynene’s engineering manager. “We’re operating based on the way the world is operating right now,” Reeves told me. “On a day like today when the fiberglass guys do not have to seal up their house, all I’m doing is following the practice in the marketplace. We have to follow suit.”

It’s time to stand up for R-38
The intent of the code is clear: every new home must be sealed against air leakage and must meet minimum insulation requirements. These are separate requirements; there is no reason to believe that a builder who complies with only one of these requirements is exempt from the other.

In Climate Zone 4 — an area that includes architect Sophie Piesse’s home town of Carrboro, North Carolina — the minimum prescriptive requirement for ceiling insulation is R-38. If a contractor wants to install Icynene insulation in a Carrboro ceiling, the minimum required depth is 8 1/4 in., not 5 1/2 in.

Many energy-efficiency experts are frustrated that the code is unevenly enforced. The solution to this problem is better code enforcement, however — not lowering the bar so that violators of one code provision can perform just as poorly as violators of a totally different code provision.

Dereliction of duty
It’s time for building officials to enforce the code as written. That means that new homes, whether insulated with fiberglass batts or Icynene, must meet both air-sealing requirements and minimum insulation requirements. Since R-20 is clearly not as good as R-38, building officials must uphold an important principle: code requirements for insulation represent the bare minimum allowed by law.

Every time that Icynene convinces a local code official into approving the installation of R-20 ceiling insulation, the company succeeds in making a sale that might otherwise have slipped away. Icynene profits from the sale — at the expense of the gullible homeowners, of course, who end up living in a house with an underperforming ceiling.

In this sad tale, there’s plenty of blame to go around. It’s finger-pointing time:

  • Icynene is being short-sighted — that’s a charitable way to express what I’m thinking — by urging builders to install less insulation than required by the code.
  • Any building department that, based on Icynene’s arguments, allows builders following the prescriptive code to install less than the minimum required thickness of insulation is failing in its duty to enforce the code. Building departments are also derelict if they fail to enforce existing code requirements for air sealing.

Last week's blog: “Blower Door Basics.”

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Feb 5, 2010 6:56 AM ET

2 More Problems with "The Code"
by John Brooks

1. the word "sealed" has no tight is tight enough?
how can an inspector judge by observation alone?

2. The code does not address thermal bridging

Feb 5, 2010 7:18 AM ET

Air Barrier
by Terry Hill

NIST did a study that attributed significant energy savings (range) to a well air sealed commercial building. Could ICYNENE be inferring here that since our product is an air barrier therefore it has inherent energy saving gains that, when combined with their insulation values equate to R38?

Feb 5, 2010 7:28 AM ET

R38 is R38
by John Brooks

Spray foam is not the only way to achieve airtightness.

Feb 5, 2010 8:18 AM ET

John, you're right
by Martin Holladay

If you or I were writing the code, of course we could do a better job. The clearest way to establish air-sealing requirements is to include a threshold -- so many cfm @50 Pa, or so many ACH @ 50 pa, or a similar threshold. But — heavens forbid! — such a logical approach would require builders to conduct a blower-door test. That's a requirement in Sweden, but here in the U.S., we're evidently suspicious of such a crazy idea.

As any good builder knows, the small investment in a blower-door test yields very valuable information. If this information is used appropriately — to do a better job of air sealing — the returns (in energy savings) far outweigh the small investment.

Now, just because the code is poorly written, doesn't mean that lax enforcement is justified. Many measures in the code are written in tangled language, but code officials still have to enforce them.

I can walk through a building site and, with my naked eyes, find examples of absurd air leaks that the builder has no intention of fixing. If I can do it with my naked eyes, so can a building inspector.

For example, how about this approach? During an insulation inspection, the building inspector asks, "I see you are using fiberglass batts. Please explain the techniques you used to ensure that each batt is surrounded by an air barrier on all six sides." If the builder can't explain his techniques, pull back a few batts and get out your flashlight.

Feb 5, 2010 8:24 AM ET

"Equate to R-38"?
by Martin Holladay

You ask, "Could Icynene be inferring here that since our product is an air barrier therefore it has inherent energy saving gains that, when combined with their insulation values equate to R-38?"

Let's say you manage to make a building completely airtight. (No one can, but let's say you do.) If you then install R-20 Icynene, what's the R-value of your insulation? That's easy -- it's R-20. It does not "equate" to R-38. Physics does not recognize this equation.

Of course Icynene can be used as an air barrier. So can taped Advantech sheathing, or the Airtight Drywall Approach, or carefully taped interior polyethylene.

The fact of the matter is that the code requires at least TWO elements relating to building envelope performance: air sealing AND minimum insulation R-values.

Feb 5, 2010 9:56 AM ET

shingle warranty when foaming under roof deck
by John M

Folks you may want to check if you put foam under a roof deck SOME shingle companies will not warranty the roof, thus just nulling it.

Feb 5, 2010 10:13 AM ET

Shingle warranties
by Martin Holladay

John M,
As far as I know, both Elk and CertainTeed will honor asphalt shingle warranties even when the shingles are installed on an unvented roof.

Remember, most builders scoff at the value of shingle warranties. The typical warranty will cover the pro-rated value of the remaining years of the warranty period -- not including labor. So if the shingles have a 20-year warranty, and you make a claim in year 13, you MIGHT receive 35% of the cost of the shingles -- but nothing for labor.

Feb 5, 2010 11:45 AM ET

Ahoy hoy
by Dan

Hi Martin
I have been following your writings with Energy Design Update and the like for years; keep up the good work.

One thing I can't understand though, is why you are supporting R-38? We all know the physics, and there's a negligible difference in heat transfer between R-20 and R-38 in a cavity application. It's just overcompensating for thermal bridging: The theoretical improvement from doubling R-value to R-38 represents 2% of the total theoretical heat loss, while your studs are leeching far more than that.

Regardless, the theoretical improvement between R-20 and R-38 is exactly that: theoretical: the building must be airtight to achieve this gain. In a real house, the anecdotal evidence that the difference in performance is so great is the result of air flow: R-38 allows less air flow because there's just so much more material.

Economically, we all know that the studs are the issue. There is so much wood in houses, that in both theory and practice you get better performance out of R-20 cavity and R-5 continuous. Why don't you champion that instead?

Fact is no buildings are airtight - it's a waste of money and a burden on our energy security to mandate the doubling of insulation requirements for all new homes when the reality is that we can all exceed the field performance of R-38 fibreglass with R-20 fibreglass and $50 in cans of Dow Great Stuff.

Feb 5, 2010 12:07 PM ET

Minimum insulation requirements
by Martin Holladay

I certainly agree with you that any builder who wants to build an energy-efficient house has to address thermal bridging. If you review the articles on this topic in GBA, I'm sure you'll agree — we've consistently advocated insulation techniques that address thermal bridging.

The fact of the matter is, a builder can't drop the ball on any of these details — air sealing, minimum R-values, or thermal bridging. All of these issues must be addressed.

The best energy modeling programs (including the Passive House Planning Package) take into account all three factors when modeling a home's energy performance.

Designers who are designing buildings to meet the Passivhaus standard or to achieve net-zero energy find that in a cold climate, one often needs R-50 or R-60 insulation — even using techniques that address thermal bridging and even in buildings with low levels of air leakage. To meet these demanding standards, R-38 just doesn't cut it — not to mention R-20.

The reason is simple: a roof insulated to R-60 loses heat at a slower rate than a roof insulated to R-20 or R-38. Measurements of actual buildings, as well as the best available modeling software, prove this to be true.

If we're going to achieve the carbon reductions necessary to preserve a livable planet, we all need to learn to build much better buildings. These buildings will have envelopes that minimize thermal bridging; are much more airtight than typical new buildings; and have thicker insulation than current code minimum levels.

Feb 5, 2010 12:28 PM ET

Equations and Evasions
by Riversong

It IS possible to write a prescriptive thermal performance equation in which, for instance, R-20 Icynene with 1.5 ACH50 has equal value to R-38 fiberglass with 5 ACH50, though the equation would be quite arbitrary since "leakiness" has different effects in different climates, site exposures, building heights, etc. And it would fuel an advertising war between insulation manufacturers that is already out of hand and out of bounds.

What's more surprising to me, however, in this wool-pulling-over-eyes campaign of - not just Icynene, but much of the spray foam industry - is that knowledgeable designers and builders have accepted the graphic representations of drastically diminishing returns for increasing foam thickness (such as this one from the "R-Value Fairy Tale web page": Icynene presents similar charts at their website.

The disinformation at the Icynene site is typical: "increasing the insulation from 6" to 12" provides an additional heat flow reduction of only 2%". It's astounding that, with the FTC regulations on R-value advertising, the spray foam industry is allowed to get away with this.

Feb 5, 2010 12:36 PM ET

by Martin Holladay

As I'm sure you know, doubling the thickness of insulation from 6 inches to 12 inches will cut the heat flow through the assembly in half.

Where does Icynene get the 2% from? I haven't looked at the page where you got the quote from, so perhaps they provide a footnote or a parenthetical explanation. But the 2% number only makes sense if they are comparing the heat flow through both insulated examples with a totally uninsulated assembly — I guess that means a tent.

But in the absence of an explanation of what they are comparing these heat flows to, their 2% number is a head-scratcher.

Feb 5, 2010 1:48 PM ET

Questionable Numbers
by Brett Moyer

I found this report on "The Economic Thickness of Thermal Insulation." I wasn't able to figure out who conducted the study, but perhaps you could share your thoughts...

Feb 5, 2010 2:12 PM ET

Many silly graphs
by Martin Holladay

James Moyer,
Thanks for the link to the Icynene document. It appears to contain much of the same information as this similar document on the Icynene Web page:

The document contains a lot of silliness. It's hard to address it all. Here's a stab at addressing a few silly items.

1. The document claims, "This test procedure (ASTM C-518-02) measures the thermal conductivity of insulation material. ... This measurement solely defines the conductive heat flow resistance of the insulation material, the R-value."

I've had to refute this fallacy so often that it is tiring to address it. Here, I'll just provide a link to one of my blogs, "Understanding R-value," in which I discuss the fallacy that R-value only measures resistance to conductive heat loss.

2. In a series of bar graphs, the author of this document compares heat loss through a tent to heat loss through Icynene-insulated assemblies. But no one really cares about heat loss through a tent. If this wall was in a house, it would be illegal.

If we're looking at, say, a ceiling in North Carolina, why not start, for purposes of comparison, with an R-38 ceiling instead of a tent? After all, that's the legal minimum. You can't go any thinner without breaking the law.

Of course, the heat loss through the tent is 50 times more than through a code-minimum ceiling. This huge difference skews the graph and leads the reader to believe that the differences in the suggested options are trivial. They aren't. Compared to a code-minimum ceiling, the suggested assembly with 6 inches of Icynene loses twice as much heat. In other words, it's significantly worse than the minimum ceiling allowed by law. It only looks good when you compare it to a tent.

3. Further on, the author compares an Icynene-insulated house, using REM/Rate software, to a house with 0.7 ACH nat. That's a lot of air leakage. Depending on what formula you use, that much air leakage translates to 12 or 14 ACH @ 50 Pa. But a 2002 study of 24 newly built homes in Wisconsin -- typical homes -- showed them to have air leakage rates averaging 3.9 ACH @ 50 Pa. In other words, new homes have air leakage rates that are only 30% as high as the example chosen by Icynene to make fun of homes without Icynene. This is a classic "straw man" example -- choose a bad house to compare your product to, and you can make yourself look good.

Feb 5, 2010 3:49 PM ET

The math is pretty clear
by Michael Blasnik

1/20 = .05
1/38 = .0263
.05 - .0263 = .0237

.0237 rounded off = .02 = 2%

They are comparing the two scenarios to an R-1 assembly.

Feb 5, 2010 4:06 PM ET

So, if you have an extremely
by Brett Moyer

So, if you have an extremely tight house achieved through aggressive air sealing, and you are reducing the thermal bridging by, lets say, R-10 insulated sheathing on the exterior... increasing the thickness of insulation in the wall/ roof cavities isn't all that important?
Im not arguing, just want to understand this...

Feb 5, 2010 4:34 PM ET

Not important?
by Martin Holladay

I'm not sure of the origin of your argument or conclusion that "increasing the thickness of insulation in the wall/ roof cavities isn't all that important."

Yes, it's important. A wall with a whole-wall R-value of R-20 will lose twice as much heat in a given amount of time than a wall with a whole-wall R-value of R-40.

Feb 5, 2010 4:34 PM ET

I should be more specific...
by Brett Moyer

Extremely tight house through aggressive air sealing
2 inch R-10 insulated sheathing, or 2 inch gap between a double wall to control thermal bridging
Cold climate design- 5,700 to 8,500 HDD
Is there reason to increase the insulation in the wall cavities from 5.5 inches to 7.5 inches by using a 8 inch staggered stud wall (common plate wall), or perhaps even 12 inch double wall? Am I wasting the homeowner's money exceeding a certain thickness of wall cavity insulation?

Feb 5, 2010 4:36 PM ET

About your math
by Martin Holladay

You're right. If you click on the link provided by James Moyer, you can read the assumptions about the R-value of the tent: "Let us include the outside air film at R-0.2 and the inside air film at R-0.7. The total R-value before the application of any insulation is 0.9."

Since such an assembly is illegal, it's irrelevant.

Feb 5, 2010 4:39 PM ET

Designing walls and roofs
by Martin Holladay

I'm not sure whether you are wasting the homeowner's money or not. It depends on what you are trying to achieve.

As a starting point, you have to meet the local building code. After that, it's up to you — or your client.

If you are advertising that you are designing a green building, I certainly hope you will exceed minimum code requirements for insulation. Many cold-climate designers are now insulating basement walls to R-20, and above-grade walls to R-40, and ceilings to R-60. But it's still legal to build homes with less insulation.

Feb 5, 2010 5:13 PM ET

I agree
by Brett Moyer

I absolutely agree if you are promoting yourself as a "greenbuilder" you better be exceeding code required insulation levels.... and by exceeding I don't mean switching from 2x4 to 2x6 walls. I've seen plenty of "green" homes built in this area with 2x6 walls/R-38 attics which sickens me.
I was just wondering if there was ANY legitimacy to the Icynene study.

Feb 5, 2010 5:22 PM ET

What Icynene says
by Martin Holladay

Icynene correctly points out that there are diminishing returns (in terms of energy dollars saved per year) from successive investments in thicker and thicker insulation. This is true of all types of insulation.

If you double the insulation thickness, you cut the heat loss in half. But an increase from R-5 to R-10 saves more money than an increase from R-10 to R-20, because there's less heat escaping as insulation improves -- and therefore fewer opportunities for savings.

All that said, thicker insulation means less heat loss. If you can afford to build it, a house with an R-60 shell will perform much better than a house with an R-20 shell.

Deciding where to draw the line often depends on your gut instinct about future energy costs. Many analysts have concluded that, even at current energy costs, code minimum insulation levels are too low. An increase in minimum requirements is therefore likely to be cost-effective.

Finally, cellulose is cheaper per inch than Icynene. That's the main reason that Icynene advocates thin insulation -- to compete.

Feb 5, 2010 6:37 PM ET

Ahoy hoy
by Dan

Has anyone tried using Fourier's to calculate the improvement offered by R-20 or R-38 over an uninsulated piece of gyprock? As is found in many existing homes throughout the US? R-2 maybe?

After air sealing and installation of R-20, what is the percentage improvement? 4%? That's still negligible for the amount of insulation.

Seems like a waste of embodied energy to me. What's the percentage improvement via R-60? That doesn't just seem like a waste of embodied energy - it is.

It'd start making sense if we started talking in real BTUs, or barrels of oil. If an unfathomable number of houses are unsinsulated, or more appropriately, not air sealed, what is the average BTU flow? What if for every 1000 BTU or barrel of oil these houses are losing, moving from R-20 to R-38 will yield a 10 BTU / 1 ounce of oil improvement? Then it stops being worth it to even discuss on the internet - you are better served focusing your attention on installing R-20 in existing building stock.

Feb 5, 2010 6:40 PM ET

"you are better served
by Dan

"you are better served focusing your attention on installing R-20 in existing building stock"

Too bad, as Martin pointed out, to do this economically contravenes code. If only there was a company willing to contravene code to improve energy performance...

Doesn't the building code have a Performance based method? Why isn't that mentioned in the original article?

Feb 5, 2010 9:22 PM ET

On the cost-effectiveness of insulation
by Martin Holladay

You ask, "After air sealing and installation of R-20, what is the percentage improvement? 4%?"
I'm not sure where you get the 4% figure. Even using the Icynene document, the reduction in heat flow from an uninsulated assembly to an R-20 assembly is a 96% reduction in heat flow, not 4%.

According to Icynene representative Ed Reeves, Icynene advocates the use of R-20 where R-38 is the minimum requirement -- even when builders are following the prescriptive rather than performance method.

Feb 5, 2010 9:25 PM ET

Icynene solution
by Doug McEvers

If Icynene is so confident they can get by with 1/2 of the code allowed R-value, they should be willing to provide monitored results for homes insulated with Icynene to prove it. I asked for this several years ago and all I got was a long rambling letter from the Icynene engineer on how their product defied gravity, it was complete garbage.

The only way I see getting to the bottom of these trumped up claims is to monitor a house with Icynene foam insulation. As I said earlier, if Icynene was so great and cost effective the production home builders would be using it.

Feb 6, 2010 6:19 AM ET

The value of monitoring
by Martin Holladay

I'm not sure that much would be gained by monitoring. I expect that if someone followed Icynene's recommendations and built a house with R-11 walls and an R-20 ceiling, it would perform exactly as expected — just like a house with R-11 walls and an R-20 ceiling.

Feb 6, 2010 6:50 PM ET

scary spray foam failures
by Li Ling Young

It's possible the whole explanation for encouraging installations no thicker than 5" is that the product has not been tested for flame and smoke at any thickness other than 5". Claiming 5" is sufficient for energy conservation may just be a dodge to avoid questions about code compliance.

The photo accompany this post does not show a framing cavity (very much) underfilled, but I commonly find 2X10 and 2X12 rafter bays filled with 5-8" of spray foam. Homes I look at are not using the prescriptive requirements to meet the energy code, so that in itself is not a problem (unless one actually wants a well-insulated home). However, what is an enormous problem, bigger even than poorly installed fiberglass in a poorly-sealed home, is the gap between the backside of the drywall and the face of the foam when it is left open to the top attic, as it would in the photo above. That not only does not meet code, no matter how you plan to meet code, but it is an inexcusable, classic bypass created by the most expensive insulation strategy you can buy.

Sure, knowledgeable installers would never let that happen, but apparently those are in somewhat short supply. As evidenced by the other scary foam failure I've seen several times: cracked and delaminated foam.

All said, foam's liabilities make the true cost of foam much higher than its already hard-to-justify cost.

Feb 7, 2010 5:00 AM ET

Maximum thickness restrictions
by Martin Holladay

Li Ling Young,
The question of maximum thickness restrictions for spray foam is complicated and often ignored by code officials. I wrote an article on the question for the April 2008 issue of Energy Design Update.

In that article, I wrote:

The uncertainties over the meaning of maximum thickness limitations were highlighted in a public letter from John Hogan, the senior code development analyst for the Seattle Department of Plan-ning and Development. In his January 23, 2007 letter to the ICC-ES Evaluation Committee, Hogan noted: “The ICC-ES reports specify maximum thicknesses for the products ranging from:
• 6 inches maximum in ESR-1383 (BioBased 501),
• 2 inches maximum in ESR-1615 (Insulstar),
• 6 inches maximum in ESR-1172 (Sealection 500), but only 3.5 inches maximum for attic walls,
• 5.5 inches maximum in NER-420 (Icynene), but 6 inches in certain attic constructions,
• 2 inches maximum in ER-3974 (Froth-Pak).“
Hogan continued, “It is worth noting that, in the IECC and the energy chapter of the IRC, the attic insulation requirements for all climate zones are never less than R-30 and in the colder climates reach R-38 and R-49. Consequently, none of these spray foam insulation products would comply with the prescriptive requirements for attic insulation when used individually. Further, the wall insulation requirements for the colder climate zones are R-19 or R-21. Consequently, some of these spray foam insulation products would also not comply with the prescriptive requirements for wall insulation when used individually.”

The article is available online:

Feb 7, 2010 1:42 PM ET

Hi Martin
by Dan

The 4% is an engineering estimate as follows:
- R-2 is the base case, uninsulated gyprock in an attic: 1000 BTU loss over period X
- air sealing to prevent convective losses, resulting in new losses of 500 BTU over period X (this improvement is substantial in existing building stock due to latent heat)
- R-20 insulation installed, resulting in new losses of 80 BTU over period X
- R-38 insulation installed, resulting in new losses of 40 BTU over period X

The above analysis is not limited to Icynene: it is a general analysis of how heat is lost through a ceiling plane regardless of insulation type. However it does illustrate why spray foam insulation as an industry is capable of generating such huge improvements. In reality, the 50% improvement via air sealing is nearly always underutilized.

It seems like a breakdown in education is pervasive as well; otherwise far more construction would use the performance method. The fact that the spray foam industry is still trying to put buildings through under the prescriptive code is laziness. With proper air sealing, I could building a house that meets the Performance Method using nothing but R-5 continuous insulation, Caribbean-style overhangs, and triple glazed windows; such is the impact of thermal bridging, solar gain, and air leakage losses of humid air.

With regard to flame spread testing, why would a company invest in fire testing at a thickness greater than what meets Performance Method?

Ling, I can't see your photo, but depending on the location of the gap, it may have no impact on heat loss.

Feb 7, 2010 3:15 PM ET

On the value of air sealing
by Martin Holladay

I have been preaching the value of air sealing for many years; no argument there. Anyone who builds a new house without doing a good job of air sealing is ignorant — and, as I've shown in this article, violating the building code.

So we're all on the same page on air sealing. In Vermont and Minnesota and much of Canada, builders of new homes have been performing a variety of air sealing techniques for many years. It should be assumed that these techniques are standard practice.

As you know, the use of Icynene is not required. Many builders are building fairly tight houses without any Icynene.

Your decision to compare heat loss in an Icynene-insulated building with heat loss in a tent doesn't impress me much. No one is building uninsulated buildings.

If you think you can build a building with R-5 insulation and still get code approval by using the performance path, so what? That may be an interesting parlor trick, but I still wouldn't want to live in your proposed building. It would still be a code-minimum building — and a lousy one at that.

We're all going to have to learn how to build much better buildings, rather than proposing fairly ridiculous ways to beat the building code at its own game — for example, by your proposed method of installing the thinnest insulation we can get away with.

Feb 7, 2010 7:32 PM ET

Icynene solution
by Doug McEvers

If you are going to continue to ramble on, at least identify yourself as an employee of Icynene.

Feb 7, 2010 8:13 PM ET

More on Ivynene
by Kirby

I used Icynene in a new house completed in 2008. Icynene was sprayed in 2007 by a local "certified, trained" whatever you want to call them. I walked the project with the Icynene installer explaining what I wanted, obviously meeting code. His cohort tried to tell me "they" are talking about that there is no such thing as conduction because the Icynene does such a great job of air sealing. I told him to quit talking so stupid. While I was picky about the installation on the walls where they neglected to get into corners in a stud space--I ended up using great stuff to fill in--I missed the roof in many places. The way these guys installed spray foam in the wall, there was no way they would achieve Icynene's air sealing properties. Icynene's R-20 is just ignorant and shows their contempt for the consumer and builder and doing the industry a dis-service. With roof inside insulation surface temperatures of about 45F with inside of 70F and outside at 9F, I knew I needed to do something. I ended up using Demilec over top of the Icynene and improved the comfort of the house and reduced the energy bill. Icynene will NEVER got any business from me, I will do everything possible to influence friends and business associates to not use their product and go with a company that has more reputable installers and treat their customers with dignity instead of like some ignoramus. Am I mad at Icynene, absolutely!

Feb 8, 2010 3:40 AM ET

by Brett Moyer

Uh can I get a translator for Dan's ramblings?

Feb 8, 2010 12:57 PM ET

I am not an Icynene employee,
by Dan

I am not an Icynene employee, nor do I support any spray foam manufacturer that is uninterested in educating their client base on the use of Performance Approach for compliance.

And I would like to state that yes, I do agree that we need to provide stronger enforcement on air sealing, and work to ensure the high performance of our building stock moving forward. However, I don't agree with the European method of over-insulating with foam board - it's just so much petroleum. Insulation has diminishing returns and embodied energy which must be balanced. You can't infinitely add insulation without significant energy investment. And then there's window to wall ratios which reduce the relevance of R-values further. Eventually you realize that it's better for national energy security to accept a certain quantity of energy bleed, which is replaced via renewable resources, rather than building out R-60 walls. R-60 walls just mean you're burning petroleum now, as opposed to over the life of the building.

And is the topic carbon reduction, or building code compliance? Because ignoring a base case as a theoretical "tent" ignores the fact that likely all of building and housing stock in the United States built prior to 1985 is either at 7 ACH50 or above, or has an insignificant amount of insulation. If you want to argue this, then pick a new year until the statement is correct. Perhaps the statement is correct for buildings built prior to 1975. Regardless, it is a significant portion of the building stock.

I am doing my best to not sound biased - I'm trying to look at the big picture here. That means ignoring building codes and focusing on carbon reductions only. Physics predicts that significant carbon reductions can be made across a large portion of the US building stock via attic application of R-20 insulation and a $50 worth of Great Stuff. I hope everyone can agree with this statement.

What about cost / benefit? The cost to upgrade a new air-tight attic from R-20 to R-38 is approximately the same as upgrading an uninsulated attic to air-tight and R-20. However, the carbon reductions derived from the existing building upgrade is orders of magnitude greater than the new building upgrade.

If I'm rambling, it's due to my passion.

Feb 8, 2010 1:12 PM ET

Retrofit work versus new construction
by Martin Holladay

1. The topic of my blog is Icynene's attempts to convince builders of new homes (and building code officials) that R-20 Icynene can be substituted for R-38 insulation in new construction. I did not address retrofit work.

2. You raise an entirely new question: what is more cost-effective, installing R-20 in an uninsulated existing house or increasing the R-value of the insulation in a new home from R-20 to R-38? Of course you are right — it's more cost-effective to retrofit the old home. No argument there. But that wasn't the topic of my article. So, should we go after low-hanging fruit? Of course.

3. I disagree with you concerning the wisdom of investing in R-60 ceiling insulation. Many embodied energy studies have shown a reasonable payback for such levels of insulation. If you want to reduce the embodied energy of your ceiling insulation, just switch to cellulose; as far as I know, it has only 25% of the embodied energy per unit of R-value as Icynene.

Feb 8, 2010 2:03 PM ET

QUALITY: Installation vs Product
by Isaac Savage


As with most trades, there are companies that "do it right" and those that are willing to do whatever it takes to get the job, even if it means doing it wrong. I hope you will be able to separate the COMPANY that did your insulation work from the PRODUCT they were installing.

The foam manufacturer can only do so much when it comes to the actual quality of the installation. They can, and do, teach proper techniques... but it doesn't mean that the installer actually does it this way. It is the responsibility of the installing company to ensure proper installation - period.

I've seen many different BRANDS of foam installed, by many different COMPANIES. A thoughtful design (location, thicknesses, etc) and successful implementation have nothing to do with the BRAND, only the COMPANY.

I suggest directing your anger toward COMPANIES that don't pay attention to QUALITY installations, instead of toward the manufacturer of the PRODUCT they're installing.

Feb 10, 2010 2:17 AM ET

Conduction + Air Leakage = Higher protection aganst conduction
by JJ Boudreau

For what we know about the actual formula to calculate R-values, it is based on conduction prevention. It has nothing to do with blocking air-leaks. This is a VERY interesting argument. One thing I want to point out is that the requirement of r-values in building codes has INCREASED 30% or more in most areas of the US in the last 5-10 years.

Please visit for the latest info on spray foam and other green energy efficiency products.

Since many structures insulated with mineral fiber types of insulation the air-leakage can easily result in a 40% heat loss/gain. The code officials decided that instead of monitoring the air tightness and retesting the actual air-sealing benefits of spray foam and other types of insulation that make a building air-tight, they would take one simple factor - R-VALUE - and go home with their Owens-Corning sponsor money.

What should take place is a total re-evaluation of the requirements to make the home energy efficient upon the sale of the home. Each region has and should have it's own set of regulations. Blower door tests should be performed to determine a minimum air-seal requirement (which exists but is overlooked). Then these test shells should be evaluated for their heat loss/gain using different products and r-values.

Once the tests are performed and evaluated new codes should be written and put into action. Of course this means that every home being built/sold will have to undergo a blower door test to check for air-tightness which brings the cost of a home inspection up significantly (one reason why it has been avoided.) Also, if the home fails the tightness factor there are few options other than spray foam and/or a complete renovation to solve the issue.

I disagree with the silly practices of Icynene but understand that they are trying to make a HUGE point when it comes to raising r-value codes to compensate for heat loss/gain. Code officials should understand the difference between the air-tightness of a home and the conductive values eliminated by insulation. Test the theories and re-write the codes.

Feb 10, 2010 11:54 AM ET

R-Values and Roofing Issues
by Rich Brown

OK, right off the bat, I AM a foam insulation contractor, and I DO spray Icynene.
All of this theoretical stuff is nice and "they should change the codes" is a great statement that leads nowhere. In the end, I still have to fill out and pass a ResCheck. And this is a ResCheck that does NOT take air-sealing into account, and in North Carolina is NOT allowed to have a UA tradeoff for super-efficient HVAC equipment. If I pass this in a house using six inches in the roof deck and 3.5 inches in the walls, where is the problem????

I do believe in performance R-values, especially those arrived at by building 30 houses in ten different climates, insulating them using batts and foam in various configurations and measuring the energy use to heat and cool them for two years. (See "The Economic Thickness of Thermal Insulation" ) I particularly believe in performance values researched signed and stamped by an engineer. HOWEVER, ResChecks and CommChecks don't allow for these, so I go from there.

Manufacturer's propaganda aside (and that is the propaganda from 20 foam manufacturers, eight cellulose manufacturers and a half dozen fiberglass manufacturers I'm talking about) the current standard is the current standard and you have to meet it, flawed or not. I'm standing here reading statements from people who are getting emotional, stubborn, angry and inflammatory about side-issues. The real one is: CAN I PASS THE CURRENT LAWS AND CODES BY INSTALLING IN THE RECOMMENDED FASHION? If not, then you need more.

As for roofing issues, I am currently in posession of letters from the following roofing manufacturers which state that they will honor their full warranty when open cell spray foam is applied to the underside of their roof decking in a manner consistant with the codes both local and international.
Coastal Metals
DaVinci Roofscapes
Life Pine Products
Pinnacle Steel Resources
Triad Corrugated Metals
Union Corrugating
Plus IKO's warranty drops to a 10-year limited from their standard warranty when insulation is placed against the roof deck.

If anyone is in possession of more than those, please let me know... I can always use more!

I guess that my biggest question to everyone is: Why are we fighting and trying to tear down one brand or another, when we should be using our energy to that lofty goal of improving the codes.

Thank you for your time,

Rich Brown
Spray Foam Contractor
Certified Spray Foam Installer

Feb 10, 2010 12:15 PM ET

1/2 lb Open Cell Foam vs. 2lb. Closed Cell Foam
by Andrew

A very interesting Marketing Approach here. While I am a Canadian Installer of 2lb. Closed Cell Spray Foam, we do agree to some degree with what Icynene is claiming. We however feel we can actually achieve a greater level of air tightness with a 2lb. Closed Cell product and have twice the R-value per inch than Icynene. Lets all keep in mind that Icynene is just a 1/2lb. Open Cell SPF.
But the core argument is sound. Greater air tightness will allow for less R-value to perform as well from an energy loss perspective in the whole building. We as an industry need to get away from Manufacturer sponsored "data" and get some real non-biased independant research. Herein lies the problem. Research is usually funded by the manufacturers. The aparatus for tests are made to skew favorable results. No wonder our Building Codes are a mess when the influencers are always manufacturers with large marketing dollars to produce research that becomes fact. How many lawsuites are pending on the missuse of 1/2 lb. foam when vapour permeance levels were higher than claimed?

Feb 10, 2010 12:55 PM ET

Air Currents Within the Insulation vs. House ACH50 Tightness
by Jan Juran

Martin: Once again you've done an admirable job of exposing misleading/incomplete claims regarding R-value. At any specified ACH, more insulation is better than less. Alternative methods can achieve air tightness, bulk spray foam is just one (rather expensive) way.
However there is a subtle distinction between air tightness as measured by a blower door test's low ACH50, and cold air currents which can circulate inside the insulation itself. For example, a house with a tight interior air barrier (e.g. airtight drywall) could have a very low ACH50 yet cold air in winter could circulate inside its fiberglass batt insulation, significantly degrading its R value.
Some years ago ORNL found that fiberglass attic insulation lost significant R value in very cold weather, as convection currents circulated cold air inside the fiberglass. Even worse, the colder the temperature, the lower the effective R value. ORNL found that using cellulose or even blowing a layer of cellulose on top of the fiberglass attic layer effectively slowed these convective air currents, preserving R value.
Fiberglass wall insulation is best installed with an air barrier on all six sides, but not all houses achieve this. A house could have low air infiltration and low ACH50 blower door results, yet cold air currents are wind washing inside the wall and ceiling insulation (although not penetrating the interior air barrier plane).
Does anyone know of any good studies which quantify an R value degradation effect, if any, of air infiltration, wind washing, or convective air currents inside the wall insulation itself (i.e., separate from the well known effect of cold air infiltrating directly into a house via holes in its interior air barrier)? Knowing the quantified magnitude of this effect for the various types of wall insulation (loose cellulose, dense pack cellulose, fiberglass kraft faced, fiberglass unfaced batt, etc.) and also for various wall thicknesses, could be a valuable guide for both new construction and, in particular, cost effectively retrofitting existing construction.

Feb 10, 2010 3:19 PM ET

Time to weigh in
by Carl Seville

This has been a very interesting conversation to lurk around, waiting for the right time to chime in. I am a fan of spray foam insulation, and I have a pretty close relationship with Icynene, having used it on all the projects I have built or renovated in the past several years and I often recommend it to clients. That said, it does appear that they are not doing as good a job at representing their product with respect to energy codes, and as Isaac mentioned, you have to separate the installer from the company. It is practically impossible to control what each installer says to their clients.
Regarding the R38 ceiling vs R20 roofline insulation, I have seen excerpts from the same study that Jan mentioned (If anyone has the complete study, I would like to see it) regarding degradation of Rvalue of loose fill insulation in cold weather due to convective currents in the product itself. That would imply to me that as it gets colder, the R20 in the roof will approach, and eventually exceed the performance of the R38 in the ceiling when cold. Since hot weather doesn't ever reach the delta T from inside to out as cold weather, there won't be any significant amount of conduction heat gain in summer (it will almost exclusively be radiant heat gain) I believe that roof insulation will match or exceed the performance of ceiling insulation at the discussed values.
Finally, I agree with Rich Brown - if your house meets (or hopefully far exceeds) the code through the performance path, then why worry about a particular level of insulation that is based on the prescriptive approach?

Feb 10, 2010 3:30 PM ET

Good arguments coming up
by Dan

"At any specified ACH, more insulation is better than less."

I don't agree with this statement. In a building with large window to wall ratios, and high levels of both thermal bridging & air leakage, and R-40 - R-60 foam board walls & ceiling (new condominium buildings?) are a waste of petroleum and detract from energy security. John Straube's presentations have the equivalent energy transfer for this type of assembly as R-2, similar to a "tent", or uninsulated assembly.

In this type of example, I hope we can agree that it's the implementation of energy saving features, and not R-Value, that dictates energy consumption. Is this applicable for residential buildings? For custom homes it is - these tend to have high window / wall ratios.

Tract built housing there's another avenue.

With regards to changing the model, moving away from minimum code compliance, and eliminating reliance on manufacturer supplied data, I've heard rumblings that the Tokyo system of condo ratings is moving to Canada. If memory serves, this is a program developed by the Real Estate association in order to give agents competitive advantage over each other, and boy have they ever taken to it. Condos are rated based on kW/sqft, and pricing is reflective of this rating.

With regards to costs associated with blower door testing, costs can be lowered by random inspection, say 1 in every 10 - 20 houses in a tract subdivision. If the test houses fail, the entire subdivision fails. The subdivision is rated by the real estate association accordingly, and the selling price is reflective of the investment in energy efficiency made by the builder.

Feb 10, 2010 4:16 PM ET

What's the problem?
by Martin Holladay

Rich Brown,
You asked, "If I pass this [code requirements] in a house using six inches in the roof deck and 3.5 inches in the walls, where is the problem?"

The answer is, there's no legal problem -- just a performance problem. There may be many ways to meet minimum code requirements. Congratulations, you found a way to barely meet code. But shame on Icynene for encouraging such tactics -- because the tactics result in underinsulated buildings.

Feb 10, 2010 6:47 PM ET

Underinsulated Buildings that Use Half the Energy?
by Rich Brown


Again, where is the "performance problem" when my customers are coming back to me to say such things as their new house that is 6,700 square feet is using the exact same amount of energy for heating and cooling as their previous three-year-old home that was 3200 sq feet? Or is their a "performance problem" with documented savings of 37% in existing homes where we sprayed only the roof and crawl ceiling with 6" and 3" respectively (TESTIMONIAL:

Are you putting your name on the line to say that their results would be another 37% or 50% better had I sprayed ten inches in the roof decks? I have a letter from a V.P. of a fiberglass manufacturer, documenting significant savings of both gas and electric in a house that was UNOCCUPIED last year and OCCUPIED this year, but had the heating and cooling set to keep it reasonable for showing the house last year. The difference is that between this year and last, we sprayed 5 1/2 inches of Icynene to the roof deck, while his family used power and gas this year for more heat and cooling, and for TV's and hot water and cooking and computers. All of these results were acheived by "meeting the minimum code requirements." So, bring on the minimum requirements with foam, as opposed to exceeding them with methods that don't include air sealing.

I, personally, would love to sell everyone a foot of foam in their roof and floor, and five and a half inches in every wall that will take it. Reality says that nobody can afford it. Fourier's law of thermodynamics suggests that I'd be cheating the customer after six inches. (Again, see "The Economic Thickness of Thermal Insulation" as documented above).

OK, I didn't want to get sucked into the sarcasm and such. Sorry. I am satisfied that the research and especially, my own experience for three years as a spray foam contractor show that there is serious benefit to spraying reasonable amounts of foam into a structure.

Thanks again for your time,

Rich Brown

Feb 10, 2010 7:41 PM ET

by John Brooks

Carl Seville :
"Regarding the R38 ceiling vs R20 roofline insulation, I have seen excerpts from the same study that Jan mentioned (If anyone has the complete study, I would like to see it) regarding degradation of Rvalue of loose fill insulation in cold weather due to convective currents in the product itself. That would imply to me that as it gets colder, the R20 in the roof will approach, and eventually exceed the performance of the R38 in the ceiling when cold. Since hot weather doesn't ever reach the delta T from inside to out as cold weather, there won't be any significant amount of conduction heat gain in summer (it will almost exclusively be radiant heat gain) I believe that roof insulation will match or exceed the performance of ceiling insulation at the discussed values."

That study that you and Jan are referring to seems to be talking about fiberglass insulation.
I have not seen it....but it Smells like a red herring.

Assume that you had a good air barrier at the attic floor, a radiant barrier roof deck and a vented attic.....
Do you really believe that R-20 spray foam at the roof deck will outperform R-38 cellulose at the attic floor?
Don't forget that there may be 25% to 60% more roof area than attic floor area.
Ask your Energy rater.

Now suppose you wanted to do something really crazy like go beyond minimum code.........
Can you increase the spray foam at the roof deck and still be code compliant?
Can you increase the cellulose at the attic floor....and still be code compliant?

Spray foam may provide an expensive way to achieve "good" performance .....
But That's It.......then you have HIT the ceiling.........
I urge you to look beyond Spray Foam and it's limitations.

Feb 10, 2010 7:52 PM ET

John, 8 & 12 pitched roof =-
by David C. James


8 & 12 pitched roof =- a 20% gain, what roof pitch has a 60% gain?

David C. James

Feb 10, 2010 8:08 PM ET

Big Hair Houses
by John Brooks

You have not been to Dallas...

Feb 10, 2010 8:34 PM ET

Thanks David
by John Brooks

I should have merely said up to 67% more....
16/12 roof pitch is very popular in Dallas now.
15/12 roof pitch would be 60% more
We have many neighborhoods with minimum 12/12 pitch mandated by the ACC and 16/12 is preferred...I have seen taller too!

Feb 10, 2010 9:11 PM ET

One word: Expensive
by Brett Moyer

It seems that all of the peeps who are in favor of spray foam in this blog are promoting spray foam as a good air sealer which equals the better performance.
Are air sealing details in wall and roof assemblies that complicated?
Is it really that hard to seal the exterior side of the wall and execute an airtight drywall install on the interior side, allowing for a fibrous insulation material such as blow in fiberglass or cellulose?
If this is too hard for you, you shouldn't be building homes!
And why the hell are people cheating insulation levels, or trying to find other ways to just meet code? Isn't this a GREEN building blog?????

Feb 10, 2010 9:31 PM ET

The proof is in the results
by Doug McEvers

I would be very interested to see some actual performance data for Icynene insulated homes expressed in Btu's/sf/hdd, please include the insulation thickness and R-value for all assemblies. If you are really brave, the ach50 as well.

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