subfloor over exposed joists

Old 09-28-04, 10:56 AM
Visiting Guest
Posts: n/a
Question subfloor over exposed joists

Hello, I have a little mudroom sort of structure that juts out from the second story of my house. The floor was rotted so I removed it and am faced with exposed joists that hover 1o feet above the ground. I was thinking I would put a thick piece of plywood on the joists and then put a thin vapor barrier and maybe thin insulating paper on top of that. Then a thinner piece of plywood on top would be the surface on which I would lay slate tiles. Does this sound right? Also, I worry that the floor would still be cold--- should I put plywood on the underside of the joists and then insulate or do you think the thin insulating paper would work. Thanks in advance, Redux
Old 09-30-04, 04:31 AM
awesomedell's Avatar
Join Date: Mar 2003
Location: USA
Posts: 2,425
Received 0 Votes on 0 Posts
Whoa, hold up!! Slate or any sort of natural stone tile require a substantial subfloor beneath them, that's alot of weight you're proposing to lay out there hanging 10' off the ground or roof. You need a L/720 deflection rating for the subfloor to be rated to hold natural stone.

If you can post back with some more info, we can help you with this. What is the size, span, and condition of the joists, also type of wood.
Old 09-30-04, 10:41 AM
Visiting Guest
Posts: n/a
more info

Hello Awesome,

Thanks for the response. Now you have me worried about the weight of the slate. It is a small room, though, five feet by seven and a half feet. The joists are five feet long, redwood, and in good condition. They are spaced at 16 inches from center to center. How do you tell the deflection rating of the subfloor? Am I crazy to put slate in there? I look forward to your response. Regards, Redux

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: