Mike Holmes doesn’t have a clue
I’m involved in rebuilding a century old school house. Dimensions are 30’x40′ it has a 2.5’crawlspace. Field stone foundation and centre bearing wall. Exterior plates are beautiful 8×8 fur beams,which are in great shape. My question is for the crawl space, the home owner wants to spray poly on the under side of the new ply and floor joists. I would rather insulate the foundation walls[2.5′] and ground. What do you say?
Replies
i'm with you.... if you insulate the walls you can isolate the crawl and condition it to suit
Thank-you for the response.
either or
Not one I fight over.
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I suppose the customer is always rite.
Interesting choice of post titles.
buildingscience.com likes it your way.
OK Mike might have a clue. But how does he get the budget. Thanx for the link.
the inspector trumps everyone, crawls space must be vented, or no? We all know what we think, but ..
I believe it's vented to the outside if unconditioned and sealed if you condition the space.
In Tennessee, I've seen unprotected crawlspaces ruin almost brand new buildings in under two years. When they finally got there, they laid down 6 mil vapor barrier on the earth, and installed vent fans that ran on a humidistat. Too little, too late. The mold down there was unreal.
thanx for the input arcflssh.I discussed it with the home owner again today,no luck. Besides the mold there is the smell of old musty dirt.
Check out what Joe Lstiburek says BSI-009.
Quoting directly from the paper:
"The easy answer is to construct a conditioned
crawlspace (Photograph 5). Construct it like a “minibasement.”
Then you can have any floor finish you
want and save a bunch of energy and money. But I
know you folks. You are stubborn and insist on
doing the vented crawlspace thing. Hey, maybe you
need to because you are in a flood zone—it could
happen that you actually have a legitimate reason to
construct a vented crawlspace. So how should the
floor assembly look?"
If you're not going to condition the space, I would definitely use foam (either rigid foam board or closed cell spray foam) and pay extra, extra close attention to sealing all cracks to cut off air movement. The foam board solution is doable, but likely very labor intensive. Spray foam is the way to go if you cannot convince the customer to seal it off and condition it.
Since I'm in a quoting mood, I'll leave you with this one:
"At the end of the day, recall that the best crawlspace of
all is filled with concrete and called a slab—or dug
out and called a basement."
Jon Blakemore
RappahannockINC.com Fredericksburg, VA
Thanx Jon that is some really good insight. Your closing quote,I think I'll pass that one on.
You could print out that BSI-009 article and hand it to the customer. It has a pic of a crawlspace with insulated sidewalls and vaporbarrier on the ground and a caption that says "How all crawlspaces should look."
Not sure what Mike Holmes has to do with your crawl space scenario or choices.....
But doesn't spray foam have to to covered with some rated fire-resistant assembly? i.e. drywall or shotcrete covering? Might be easier to insulate the perimeter walls and coverer with approved fire rated assembly than to do the floor. Plus any mechanicals in the floor get entombed, making future repairs/add-ons very difficult.
Also, check your local codes if even allowed?
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?