I have a small addition ( 10′ X 23′ mudroom) that is on the back end of a larger attached 2 car garage addition. The mud room floor is framed with 2 X 8 floor joists that sit on a 2×4 sill and a 4″ curb that was poured as part of the garage slab. So there is a 5 1/2″ space between the bottom of the floor joists and the concrete slab. There’s a 6 mil poly vapor barrier under the slab. How should I insulate the mud room floor? I was going to lay down 2″ of blue eps foam board over the slab to serve as an additional vb and then maybe put in R-25 bats between the joists (16″ o.c.). Should the area be vented? Maybe I should add a couple of vents just to take care of any stray moisture that may come up through the slab? Thanks!
Jim
Edited 12/23/2004 1:36 pm ET by Coz
Replies
I'm responding as much to get others to look at the thread as to answer your question.
In the first place, the "5 1/2" space between the bottom of the floor joists and the concrete slab" is, I think, a code violation. Too late now I guess.
Ideally, I believe, the perimeter of the "5 1/2 space" would be insulated and a vent from the living area would blow conditioned air into the space.
But is the mudroom heated???
Where are you located??
Is the mudroom floor installed??
Rich Beckman
Another day, another tool.
coz... you've got the vapor barrier..
if you are confident that moisture is not going to be a problem..
i'd use 1" EPS with borates ( trade name Performguard)..
the purpose of this is to create one more line of defense to moisture migration ..
then i'd blow dens-pak cellulose into the entire void.. and never look back..
you treat it like a sealed crawlspace