Another insulation ID question

[cbass]

I was in a house today that was around 60 years old, with many recent renovations. In the crawlspace this green very hard spray insulation was all over the foundation walls, sill plates, rim joists, and duct work. I even found it in between the framing in the attic. Is this some kind of new spray insulation kit like this?: http://www.sprayfoamdirect.com/ Wouldnt this be dangerous to install this all over the joist ends, rims, and various other framing (trapping moisture, termites etc.) preventing inspections. The sellers disclosure noted previous termite damage and the home was already treated with an annual inspection schedule (who knows what they were looking for???). Would you do anything other than simply listing it as a limitation of what was or was not visible at time of inspection? We dont see spray insulation to much around here. Thanks

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[Marc]

The selling price of the largest available package of that product comes out to almost $14.00 per cubic foot of insulation. The big orange box sells unfaced fiberglass batt insulation for about $0.50 per cubic foot. The batts are advertised with an R value of almost half that of the foam.

I couldn't find any information on the green foam site regarding any standard that their foam had passed.

Marc

[cbass]

So, would you inform your clients of anything regarding this product other than that it is covering many elements that we would normally inspect?

[David Meiland]

Might not be easy but it would be worth identifying the manufacturer and type (open vs. closed cell) of insulation. Open cell is fairly vapor-permeable and plenty of cases are now cropping up where moisture has migrated thru the foam to condense on the cold surface behind, causing the foam to become saturated. This is particularly tragic when the cold surface happens to be wood. Also, in many cases the foam needs to be protected by a thermal barrier, such as drywall or certain approved spray-on coatings. Foam on the ductwork is probably a good thing, at least from an air-sealing point of view, and some of the building science folks are recommending foam directly on stone foundations in some cases.

[Marc]

I would look at the impact of that foam on the overall envelope design and comment if needed. The manufacturer says it's closed cell, so it's also a vapor barrier (perm = zero). That foam can do much more harm than good if it causes moisture to build up and condense anywhere within the wall cross section, unless a drainage plane is present at that location.

Marc

[Marc]

Mason Knowles wrote a nice article on foam for the September issue of JLC. There's some information available at his website if you're interested.

http://masonknowles.com/

Marc

[cbass]

Thanks for the information guys.