Slow cure foam injected behind fiberglass in walls?

Has anyone heard of injecting slow rise closed-cell polyurethane foam (such as Foamo's HandiFLOW) into wall cavities behind existing fiberglass batts?  or injecting it into empty rafter bays? I have heard of a proposal to do that, and I am very skeptical that it would work effectively.

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Foamo's Handi Flow pour in place product is not intended to be used in vertical applications. It is formulated to be used in molds which are clamped in place. Using this product for residencial walls seems to be an installer beware issue.

Sorry I only know about Icenyne's system from a few years ago which is an OC product - that said you might want to check this thread and seeing David I know is on this board - you might try sending him a message

it wont.

Beware of what you are buying.  There is a rebirth of Urea Formaledhyde foams underway.  they are sold as 'TriPolymer' foams and they are marketed for injection in walls filled with fiberglass.  Are you sure it was urethane you were proposed?   


there are 'pour' versions of urethane.  the open cell companies sell slow rise for retrofit applications.  I tried that a couple times about 18 years ago and found it fills EVERYTHING.  it comes out the phone jacks, the three holes in each side of each outlet, between moldings and sheathing, EVERYWHERE.  it also can push plaster & lath off the studs.  great at getting it all, bad at knowing where not to go.  as it rises, it has the consistency of the froth on top of a glass of beer.  try containing some thing like that that is also hot and slippery. 


closed cell pour foam is used for floatation and to fill SIPS panels.  it can be used to lift highways that have sagged by bridges.  i think it woudl probably push the finishes off a wall. 

Thanks for the replies. I had given a proposal to a client to use dense-packed cellulose, after removing much of the fiberglass. They had received another proposal for this closed-cell foam. I told them that I was very skeptical of that method and told them lots of reasons why. I am trying to find out more about that proposed method.


I gave a thermal imaging inspection to a man who just had his house injection foamed and he felt no difference, my inspection clearly showed his problem was with air infiltration and thermal bridging. The foam insulation in the bays had no significant benefit over the fiberglass he already had. It's too bad he had the thermal imaging done after he spent all that money on foam. I'm not saying foam is useless but in that case it was.

The Thermal Avenger

Brad,I had given my opionion on this in another discussion. You had originilly asked about a POUR in place foam. The injected foam as Pat mentioned is a urea tripolomer and my experience from using it is as follows. IIt gets in elec. boxes and ozzes out. It will expand and blow out a wall. It does bridge if not installed carefully. It does shrink around all framing members, up to 3/8 to 1/2 in. It is expensive. The Rvalue is diminished because of the shrinkage. DENSE PACK is the way to go.

InsulSmart is an ultra-low emissions, low shrinkage injection foam designed primarily for retrofitting existing framed structures. An advanced formulation - InsulSmart MH - may be installed in California without restriction, and may be installed in New Jersey and New Hampshire where traditional UFFI formulations are banned. Plletized sacks of InsulSmart resin are shipped in a dry-powder format. InsulSmart foaming catalyst is shipped in 1 gallon jugs as liquid concentrate. Attached are pics of Insul Smart installations from our customer training sessions.  These installations are behind clear Plexigass for training purposes. The pics with less shrinkage typically have an existing fiberglass batt in the wall.  The pics with slightly more shrinkage are from empty stud cavities.  All of these have been aged at least 2-3 months to allow the foam to fully cure. As one can see, some shrinkage occurs, but it is much less than other brands of aminoplast injection foam.

Sorry Bob, but InsulSmart doesn't cut it. I checked the manufacturer's website. Nowhere does it mention that it is an open-cell foam, yet it has a perm rating of 10. Instructions for retrofit applications specify that it must be done in 4 ft. lifts, max. It is much more expensive than cellulose and more expensive to install. It shrinks, so it is not great at air sealing. Its R-value is not much better than fiberglass or cellulose. The manufacturer even avoids the whole story with MSDS by only presenting MSDS data for the finished product, not the individual components!


We're the manufacturer. All injection foams are considered open-cell foams. We recommend 4 ft. lifts in case fire blocks are in place. Our spec also says the foam may be injected in 10 ft to 24 ft lifts in CMU walls.

Shrinkage is typically 1/2% or less for foam in enclosed cavities. The installed R-values shown in our literature take that into consideration. Cellulose settles, Fiberglass batts compress and not always skillfully cut and fitted. Installed R-values quoted for those products assume perfect workmanship. Ours account for shrinkage.


Yes, it's more expensive than cellulose but open-cell SPF is even more expensive. Last time we looked foams were taking market share from fiber insulations.


InsulSmart is a non-expanding foam; thus, no concerns re: binding sash windows. The R/inch is 4.6 for standard InsulSmart and 4.4 for InsulSmart MH. Higher than open-cell SPF, dense-pack and wet spray cellulose and fiberglass.


Structures insulated with InsulSmart perform well. Installed performance is the proof of the pudding.



My original post was concerning a closed-cell foam in a retrofit situation. Your product surely has some benefits, but there is no "perfect" insulation.

Your statements and the manufacturer's selectively missing information would lead me to not trust your product at all. Cellulose does settle, IF it is installed loosely. The standard today for installing cellulose insulation in closed cavities is to dense-pack (DP) it. DP cellulose does a great job of stopping air infiltration and it does NOT settle. Although it is not a vapor barrier, it is hydroscopic and diffuses moisture very well. In the northern climates, it handles moisture very well, where the vapor drive changes from season to season. Open-cell foams do not deal with moisture very well. Cellulose has antimicrobial additives, just as your foam does.


If InsulSmart is a non-expanding foam, then it can't do a very good job of compressing fiberglass batts in retrofit jobs.

Remember to "always look at the whole picture" and that "the more you look, the more you see"





Over time, DP cellulose has earned a loyal following of advocates; however, DP cellulose is not the only option available. The effectiveness of all insulating materials hinges largely upon 1) workmanship and 2) matching materials with needs and priorities. Installing a material to do something it's not designed to do generally leads to disappointment and unhappiness.


In 1983 I co-wrote AIR INFILTRATION CONTROL CONTRACTOR MANUAL for ICAA members. Field studies since then confirm what was known then as to the points of infiltration:


Sole Plate - 25%    Wall Outlets - 20%    Duct System - 13%    Exterior Windows - 12.5%

Vent Hoods - 6%    Fireplace - 5.5%        Recessed Spot Lights - 5%     Exterior Doors - 4.5%

Dryer Vent 3%       Sliding Glass Doors - 2%      Other - 2%       Bath Vent - 1.5%


Of these infiltration sources, only the portion of air infiltrating through Wall Outlets @ 20% is influenced by the selection and workmanship associated with wall cavity insulation. Clearly caulking and sealing framing joints and through wall penetrations ought be the major component of any air-infiltration abatement strategy. What's installed in stud cavities impacts only 20% of the total. InsulSmarts primary function is insulating, not plugging air leaks although it does reduce the rate of air flow through the envelop. That was the point in preparing the manual for ICAA in the immediate aftermath of OPEC's oil embargos and the public's demand that home builders do something to improve energy efficiency.


Open-cell foams deal with moisture in the form of vapor quite well working in conjunction with properly placed and installed vapor retarders. Open-cell foams are not intended to retard vapor any more than is DP cellulose, FG batts or any other porous cavity insulation. As InsulSmart cures, it releases the make-up water. If subsequently wetted, it subsequently releases that moisture, as well, to return to fully effective functionality. InsulSmart contains significantly more resin than do traditional masonry foams. The percent of make-up water to resin ratio is much lower. It handles vapor transmission at least as well as DP cellulose.


As to compressing FG batts, InsulSmart is injected under modest pressure sufficient to compress light density (R-11) FG batts significantly, and higher density (R-13 and R-15) to a lesser extent. The greatest need for upgrading wall insulation is in older housing stock where little or no wall insulation may have been installed.


Back in the "good old days" when I entered the industry Rock Wool and FG batts had about equal market shares. In the late 60's, Owens-Corning causes quite a stir with its' "3 and 6" program advocating 3" of wall insulation and 6" of attic insulation as an improvement over the then prevailing standard 2" and 4" respectively. There was little or no mention of R-values.


So, in view of the fact that a lot of older homes have either no wall insulation or very thin wall insulation or very light density wall insulation, InsulSmart's abilty to compress and/or augment existing conditions are not in question.


As to selectively missing information, what information is missing? We portray InsulSmart as transparently as possible. If we can improve, please suggest how? Beyond discounting installed performance to account for the degree of shrinkage anticipated, what else needs be disclosed?


Though you may never become an InsulSmart advocate, I hope my responses to your thoughtful questions and observations expand your awareness that InsulSmart is at least a legitimate option worthy of consideration.


Best regards,



Okay, here is my last post on this thread. I stated in a previous post that there is no perfect insulation and that your product has its benefits. Nowhere did I state or imply that cellulose is the only insulation to use.

You stated: "Open-cell foams deal with moisture in the form of vapor quite well working in conjunction with properly placed and installed vapor retarders ". The key is that open-cell foam, by itself, does not deal well with moisture and requires a separate, properly installed vapor barrier. Cellulose does not require a vapor barrier, and in fact it is not recommended.

I sure would like to know where all of that old housing with little to no insulation is located! Most of the old housing stock that is over 70 years old that I have encountered has been remuddled with more than 2" of insulation.

How does your foam deal with a wall insulated with rock wool? Not as well as if it were fiberglass and not as effective as cellulose (which may not get dense-packed but will still fill it in).

As to missing/misleading information, I have already referenced some, such as why are the MSDS' for the individual components not available on the website? The only MSDS is for the completed product, which appears to be very benign. Are the ingredients that safe before mixing? Nowhere on the manufacterer's website could I find any reference to whether InsuSmart is an open-cell or closed cell foam. Claims that cellulose will settle are as outrageous as stating that InsulSmart is easy to install with perfect results. We know that if the mixture or temperatures are not within limits, the product will not set up properly or otherwise not behave as expected.


There are a lot of different insulating materials available. Each has different characteristics and may be more appropriate in certain situations than others. All of the existing conditions and all of the characteristics of each insulation must be considered before choosing a product or assembly of products.

In my opinion, not only is this discussion of InsulSmart off topic, but InsulSmart is not an appropriate choice of insulation for most of the situations that we encounter here in Vermont.


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