Icynene and Ventilation

[jcallan]

Inspected house built in 1920’s that have been updated in 1999. Many of the 2nd floor windows {installed in 1999} have mold/mildew. The house attic has an air handler in the attic; system was operating okay, although the filter was dirty. The attic sheathing and walls is totally covered with this insulation which I have never seen before. I believe it is "Icynene Insulation System" I always thought attic should have ventilation. The roof has a ridge and soffit vent's but with this product it appears useless. My understanding is the house is not used much. The owner was last there in July 2005. Could this foam insulation product be causing the mold/mildew on the windows?
Can this be good for roof shingles,attic sheathing?
Thanks
John Callan

[Jay Moge]

never seen that done before. i think it's the 2 part epoxy spray foam. it's becoming more popular now, but i've never seen (nor would i recommend) it being applied directly to the roof sheething, especialy in our neck of the woods. an air tight attic is NOT a good idea.

[phinsperger]

If there was a continuous ridge vent along the entire length of the ridge AND continuous soffit vent AND the two were connected together with a continuous baffle in each and every cavity before applying the spray foam over the baffle then I would not have a problem with this. In all likely hood that was not done but is not possible to tell from the photo. In any case this is has more to do with the life of the roof.

The spay foam installation would have reduced the air leakage in the home which will have an impact on internal humidity levels to some degree.

By applying the spay foam to the underside of the roof deck they have effectively moved the outer building envelope so that the attic space now becomes interior space. It needs to be treated as such. You mentioned that the air handler is in the attic. At the very least a return air duct should run from the attic space to the air handler especially in the air handler is well sealed.

They basically have two choices;

1) remove the spray foam which will extend the life of the roof, possibly eliminate the moisture problem and increase their energy bills. Remove/reduce unwanted moisture sources from the rest of the house (ie open sump pit, site grading, etc).

2) leave the spay foam, install ducting to add the attic space to the conditioned space by the air handler. Remove/reduce unwanted moisture sources from the rest of the house (ie open sump pit, site grading, etc). Be prepared to replace the roof a lot sooner.