Thread: Attic Foam Insulation

I have a client that is considering installing Incylthane 500 foam product in his attic space.He asked me what I knew about the product and was not able to provide anything for him.Its appears to every costly, any information or advise would be appreciated.

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Larry,

First, it is "Icynene" (unless there is a knock-off product by the other name).

Second, go here: Icynene® Spray Foam Insulation & Air Barrier Material – Energy Smart Foam Insulation

As long as the attic is sealed (not ventilated) and the work is done correctly, the system is a good system.

A lot of the spray foam guys put in less than the code requires because it is so expensive. They sell that the air sealing characteristics make it a higher R value. They will likely sell him an R24. As we know code is the minimum. They should be shooting for R50-60 in most locations.

Air sealing combined with cellulose with be more cost effective in reaching a high R value.

Icynene is the brand name for an open cell foam They are many brands of open cell foams. Open cells are about R3.5 per inch and closed are R6 per inch.

I would not put fiberglass in an attic. It will lose 30-40% when it is either real hot or cold.

Larry,
I agree that it's good stuff however, you might want to consider the info in the letter from Owens Corning when advising your client.

Spraying foam insulation into an existing attic requires some planning. For example, is the HVAC system going to be re-sized? It is probably already over sized and when the foam is applied it will be even more over sized. Ensure that the moisture can leave the house!

Originally Posted by stanley frost

Larry,
I agree that it's good stuff however, you might want to consider the info in the letter from Owens Corning when advising your client.

I am not sure about the whole spray foam idea directly to the underside of the sheathing.

One of the major concerns is a roof leak in the future. It may be slight but it could cause severe damage over time and no one will know it until it has taken it's toll.

I have done roofs with Sips but the way we used to do it was to attach the SIPs and then apply strapping and then another layer of sheathing and then the roof covering. This supplied the entire space to vent up thru the ridge vents. Also any slight leak would be dried but you still have a problem with a major leak. But if we keep in mind that a full maintenance schedule should be done on every home and if it is will cancel out most of the problems noted above. I am not sure how they do it today.

I doubt it would have an affect on the roof shingles other than a year to foam the underside of the sheathing. I am not in completely agreeably with with the air having to penetrate the insulation as in loose fill insulation. Cellulose is a great insulator. Much better than loose fill fiberglass and there is practically no air blowing or moving thru the upper layer of the cellulose when applied to an attic floor. I think loose fill fiberglass is an awful waste. Cellulose does break down over time but you can always add to it many many years down the road.

As far as a home being tighter and a system being to large because you ad foam......It may have a slight affect but tight homes of all kinds should have some outside air added to the mix anyway or you will have an unhealthy home. By doing so you add more moisture to the system that the system ha\s to remove as it comes across the evap coil.

Adding or just foaming the floor of an attic is another whole story and I believe the best route one can go. Of course in an existing home all the loose fill or batts would have to be removed. Of course if it is a new home the HVAC system can be sized properly if it is known that foam is going to cover the ceiling.

Way to many ifs, ands and buts about existing homes that have to be brought into account. New homes are easier to figure.

Polyurethane Spray Foam Insulation.

Originally Posted by Larry Hood

I have a client that is considering installing Incylthane 500 foam product in his attic space.He asked me what I knew about the product and was not able to provide anything for him.Its appears to every costly, any information or advise would be appreciated.

Your client should do the 2000 product, which of course is even more costly. I'd only use the 500 product if my primary concern was air sealing, which likely isn't a concern in a ventilated attic.

Doing the foam system as a retro-fit is probably not going to be cost effective...actually, unless you have the lifespan of Methuselah, you are never going to recoup the cost. IMO

Foam Insulation is very expensive even on new construction. To get a contractor to foam and properly seal the attic is going to add probably 20%-30% per sq.ft. when compared to the same attic (area) sprayed, if it were a new construction aplication....It is going to be almost impossible to seal at the eves....and then what about the existing walls? for the foam system to be effective it needs to be a complete air seal.

This type of insulation method should be a part of a well planned system designed to include, and match the heating/AC system to the (New) home.

If an existing home; It would probably be wiser and even less expensive to upgrade widows/doors (if needed) and then put a heavy blanket of CELLULOSE in the attic to bring up to an R-50-60.

Hi Larry,

There are two products being discussed here. The product that you mention is a Trade Name under the Polymaster Brands from Knoxville, TN but it is manufactured by North Carolina Foam. This product is an open cell and is slightly more expensive than some of the other products out in the marketplace. The other product - Icynene is a competitive open cell product that is extremely expensive. Two separate products manufactured by separate companies but both fall under the open cell spray insulation category.

As for the installation, we traditionally recommend and install closed cell spray insulation and if the house has a ridge vent or soffit system, we would normally staple plastic baffles to the underside of the roof and then apply the closed cell spray insulation to the baffles. Everyone has their own opinion as to whether or not the spray application should be applied to the underside of the roof. There are also many debates as to whether to spray the soffits and the ridge vent closed. My dad was an engineer and he always believed that a house is a living breathing organism that needs to breathe. Having too tight a house can create a whole host of other problems that would be too lengthy to discuss here in this response.

I would never spray the attic floor. You are looking to spray the space where the dew point is being achieved. I also disagree with the payback observation by one of the other posts. In all of the homes and commercial buildings where we have installed open and or closed cell spray insulation, we have seen and been told by many of the owners that the payback was immediate in heating and/or cooling costs.

Finally, I would never consider installing cellulose insulation in any application whether it be a house and/or commercial building. If you are considering cellulose versus the spray insulation -- hands down spray insulation will last longer, prevents mold/mildew and the payback is immediate.

I hope this helps.

Mary Beth Yannessa, President
Tridon Industries, Inc.

Vented or Unvented Attic? | GreenBuildingAdvisor.com

The article requires a subscription, but they have a free 10 day trial offer.

The issue of moisture is addressed by either using the 2000 product or covering the foam with a vapor barrier. However neither product addresses the issue of the asphalt composite shingle warranty.

Building Science Corp has written a number of articles on unvented roof systems. See the following:

http://www.buildingscience.com/docum...-roof-systems/

http://www.buildingscience.com/docum...nt-on-venting/

BSD-102: Understanding Attic Ventilation — Building Science Information

Unvented Roof Assemblies.

These may be of use also.

Mastering Roof Inspections: Attic Ventilation Systems, Part 1 - InterNACHI
Mastering Roof Inspections: Attic Ventilation Systems, Part 2 - InterNACHI
Mastering Roof Inspections: Attic Ventilation Systems, Part 3 - InterNACHI

Thanks for all the replies. Here are the conditions: Older home completley remoded,new duct system,new roof shingles,vented soffits, roof pitch 2 1/2 in 12,R-15 -R-20(existing ) insulated,no provisions to get to most parts of the attic,12-15 recessed lights thar would need to be protected from being covered in insulation and quotes from $8K-$18K,+- living area of 2,500 S/F. Only excess to attic is pull down in garage.

Originally Posted by Mary Beth Yannessa

Hi Larry,

There are two products being discussed here. The product that you mention is a Trade Name under the Polymaster Brands from Knoxville, TN but it is manufactured by North Carolina Foam. This product is an open cell and is slightly more expensive than some of the other products out in the marketplace. The other product - Icynene is a competitive open cell product that is extremely expensive. Two separate products manufactured by separate companies but both fall under the open cell spray insulation category.

As for the installation, we traditionally recommend and install closed cell spray insulation and if the house has a ridge vent or soffit system, we would normally staple plastic baffles to the underside of the roof and then apply the closed cell spray insulation to the baffles. Everyone has their own opinion as to whether or not the spray application should be applied to the underside of the roof. There are also many debates as to whether to spray the soffits and the ridge vent closed. My dad was an engineer and he always believed that a house is a living breathing organism that needs to breathe. Having too tight a house can create a whole host of other problems that would be too lengthy to discuss here in this response.

I would never spray the attic floor. You are looking to spray the space where the dew point is being achieved. I also disagree with the payback observation by one of the other posts. In all of the homes and commercial buildings where we have installed open and or closed cell spray insulation, we have seen and been told by many of the owners that the payback was immediate in heating and/or cooling costs.

Finally, I would never consider installing cellulose insulation in any application whether it be a house and/or commercial building. If you are considering cellulose versus the spray insulation -- hands down spray insulation will last longer, prevents mold/mildew and the payback is immediate.

I hope this helps.

Mary Beth Yannessa, President
Tridon Industries, Inc.

Very interesting read. Having sprayed hundreds of attic systems since late 2000 I can attest to the great benefits of using this product. Thread bookmarked.

Thanks again,
Mike
MJL Associates :: Connecticut Spray Foam Insulation

If there are gas furnaces, water heaters, stoves, ovens, or fireplaces etc. then significant investment is also necessary to provide make up air and safe exhaust ventilation.

Originally Posted by Darrel Hood

If there are gas furnaces, water heaters, stoves, ovens, or fireplaces etc. then significant investment is also necessary to provide make up air and safe exhaust ventilation.

Agreed, this type or rather method of insulating needs to be considered as part of the design of the house as a system or you could have some problems like Darrel mentioned with make-up air, also moisture problems or just general indoor air quality.