foam insulation in an attic area
I have a house that is 18 years old in Maine. I talked with someone about adding more insulation to the crawlspace attic area. I have fiberglass up there now. They suggested the foam type stuff that could go between the studs. My question is that putting this type in would cover up the ridge vents and maybe the soffit vents. Would that be bad for my house without that ventalation?
Re: foam insulation in an attic area
I'm guessing from your expaination that the fiberglass is on the rafters, not the Kneewall floor and wall. When insulating a kneewall, you have to decide between these two options. Do I keep the kneewall in the envelope of the home by insulating the rafters? If so, venting is not required, and would negate your insulation efforts. The other option is to insulate the walls and kneewall floors, then the kneewall must be properly vented. Which option I choose for a home I'm working depends on the situation and wants of the homeowner. If I saw existing insulation on the rafters, I would usually install a tyvek material used for mobile home bellys over the existing insulation, making sure to include the gable end wall, bracing with lath or plumbers strap, then dense packing, blowing cellulose under the existing fiberglass to a value or 3.5 pounds per cubic foot.