It appears that all the walls have been insulated with the blue rigid foam insulation as suspected. However, in addition, the previous owner applied drywall directly over the foam with no vapor barrier. Is it worth the effort to remove all the blue foam insulation and drywall and replace it with the R-28 insulation and vapor barrier? Regarding the drywall, is this a good idea? My understanding that pant legging entails incasing the existing ductwork inside a larger one. Is this correct? As well, how far into the crawl space should I go?
Answer:
If the rigid foam insulation is 1.5" thick or more, it is a vapour barrier and should be removed before more insulation is added because it can cause too much condensation. Pant legging only means introducing a "Y" to the ductwork so one branch can supply air to the floor grill and the other to the crawl space. If this were my place I'd put the Y a couple of feet into the crawl space.
