Quote:
Originally Posted by mk1st
warmwxrules: I would not recommend using any fiberglass in a basement due to the potential for condensation (unless your foundation happens to be insulated already on the exterior). Also, insulation needs to be in contact with the surface it's insulating so leaving a gap will not result in good performance
|
Well, I have seen Fibreglass insulated basemen using 6 mm Plastic sheeting as Vapor barrier that lasted over 30 years... being fully dry and still insulating very well. They also use non contiguous 6mm plastic sheeting under the ground line... on the inside of the concrete wall. (DIY, Insulation specialist and contractor jobs alike -- All following the Canadian recommendation by Energy, Mine and Resource Canada).
I have seen basemen insulated with expanse foam (White foam)... Completely ruined after only 6 years... and full of black mildew. (All DIY jobs)
I have seen wall with extruded foam that end-up full of mildew... With gypsum drywall completely wet and deteriorated... with paint pealing. (sometime build by DIY but often by 20$/hours man of all trade construction worker)
If your basement have water/condensation problems... call in the expert or investigate the cause. You likely need water proofing, better drainage around the house or better ventilation. If you are located in the north of USA or in Canada and you have a very well insulated house... you generally need mechanical ventilation (some stirring of the air) or a dehumidifier to prevent the condensation in the basemen -- especially in the spring and early summer when the heating demand is lower.
I never have seen any major problems with sprayed foam insulation... but the fact that all the jobs have been done by a single certified insulation company with a few engineers on payroll might have help tremendously. (all with proper mechanical ventilation mandated by the building code of Québec, Canada)
-------------
Did I replace any fibreglass basemen insulation that was properly done... Actually, yes... following the flooding of a basement -- But, under these conditions, we replace all type of foams as well -- unless we can dry them very quickly (2 days maximum I think) -- and that we can ascertain that the water was not polluted/contaminated.
Essentially, if it get flooded by a river or the sewer, everything but the concrete foundation get replace. The concrete foundation get clean by an Enzyme treatment.
----------
Well, you will have to define touching: In cold climate, a spacing of 1/2 to 3/4 inch between some layers is often use. For example, if you use Aluminium foil insulation as vapour/radiant barrier over fibreglass insulation between 2x4 or 2x6.