bonus space insulation options
Ok, I am new here so be gentle. I have just moved into my 1st ownerbuilt home and am quite happy with my work so far. Let me give you a little back ground on the house to let you know where I am going with it. I am a bit of an efficency nut, with a buget of course. so I put in insulated windows, dense pack cellulose(couldn’t afford spray foam), superior wall basement, with over insulated band joist, and Geothermal heating/cooloing, I personally sealed every nook and cranny with caulk anf foam.
ok, my question is the bonus space above the garage that is ready to be finished, by me, except drywalling/mudding. what should I do with the cielings and kneewalls for insulating it properly. I don’t like fiberglass performance, because of air infiltration. I have 2×10 rafters then 2×4 coming down for kneewalls and around 3 dormers. I am considering spraying the deck myself with fomo.com spray foam. I currently have a ridgevent up there so I will probably put rafter baffles up and just spray over them, sound ok?? insulating my 3 dormers would probably be with spray foam myself, from fomo.com. the kneewalls have me kind of in a jamb though. when I got the cellolose sprayed for the house they would net off some areas in my house and spary into the netting if there was not any sheathing behind it and it worked good. well, I don’t have a wet cellolose spraying machine.so what should I do with the kneewalls? BTW the floor is already dense packed with cellulose above the garage ceiling, so that is covered.
Do any of you have any experience doing the spary foam yourself, preferably fomo.com or any other if you have any other place to get sprayfoam?? Any tips or advice for bonus space finishing above a insulated garage? thanks
Replies
>> OK, I am new here so be gentle.
The cyberspace version of the "Kick Me" sign.
anybody?
Bring the kneewalls inside the thermal envelope of the house. Trying to insulate from the peak, to the top plate of the kneewall, down the kneewall, then from the sole plate of the kneewall, along the floor joists, and out to the exterior wall can be...shall we say...not too effective at times. Simply insulate the rafters from peak to plate.
Bringing the area behind the kneewall into the thermal envelope and makes it more user-friendly for storage, etc.
Spray foam would work fine. Another DIY-friendly method is to put 2" foil-faced polyisocyanate insulation on the faces of the rafters. When installing the sheets, leave a 3/8"+/- gap between them. The sheets don't have to break over studs, they can break over the middle of a rafter bay.
Once they're all up, use canned foam to seal the gaps. Then Al tape over the canned foam. Then horizontal furring strips screwed through the PI into the rafters. Dry blow cellulose into the rafter bays.
Screw drywall to the furring strips.
Viola!
An air-tight attic.