Foundation insulation
I have a 24’x30’crawl space that is adjacent to a furnace room in a finished below grade basement. The crawl space and furnace room are connected by a chest high 4’x3′ wall opening that has uninsulated heating ducts and a return trunk running through it from the furnace. The crawl space foundation is between 24″-30″ high and is of old rock and mortor construction and in good shape. The floor for the living room floor above is uninsulated.
My issue is that cold air from the crawl space flows into the basement furnace room like a river. To fix that I’m thinking about insulating the foudation walls of the crawl space but also keeping the space conditioned, which I think it is considered now. The options I am considering are verticly placed fiberglass bats tight against the foundation walls and tucked into the floor joist end bays or have the whole thing including the dirt floor sprayed with urethane foam. I have about 120 ft2 I figure.
Do you guys have any opinions of that plan or other things I need to think about or is it all clear as mud?
thanks
Replies
cango..... foggedabout the fg batts
how uneven are the walls ?
if i could, i'd be thinking about 4" eps (PerformGuard ) fitted up into the joists.... and dug into the dirt ...you can buy these panels with 1/2" gypsum bonded to the finish side so there will be no firecode issue
compare this cost and your ability to do-it-yoiurself
vs.
cost of having it sprayed.... and i don't think i would spray the floor
assuming this is a dry crawl
Mike, do you get your Performguard from an R-control dealer or your lumberyard?
Branch River Foam in N. Smithfield , RIMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Place a 6 mil poly vapor barrier on the dirt floor and run a few inches up the walls, and spray foam the walls and up into the band joists, not the floor.
Solar & Super-Insulated Healthy Homes
Run the vapor barrier up about a foot, and secure with adhesive. Leave a little extra fold at the wall/floor intersection, it's tough crawling around with spray equipment, and you don't want to inadvertantly pull a gap in the plastic.Check and see if you need a termite inspection area at the top of your foundation wall before you spray the whole thing, it's pain getting the foam off. Now you see this one-eyed midget
Shouting the word "NOW"
And you say, "For what reason?"
And he says, "How?"
And you say, "What does this mean?"
And he screams back, "You're a cow
Give me some milk
Or else go home"
when you have the floor sprayed keep right on up the walls. however you will need to cover that foam with sheetrock to make it fire resistant.. so incorporate some 2x2's to screw the sheet rock to.. you can do it the easy way, use a construction adhesive don't try to use anchor bolts etc..
Basic concept is good ... IMO. I agree, though, DON'T foam the dirt. Put 6mil VB down on the ground to control moisture. Batts on the perimeter is OK, I think. If you go foam ... check the code ... another poster implied a fire safety issue. Most/many foams require they be covered by a fire resistive construction (e.g. gyp board) ... i.e. you can't leave them exposed (although maybe a crawlspace isn't considered 'exposed'?
Food for thought.