We are enclosing a screened in porch (windows and hardie panel walls replacing screen) to make our porch a 4-season room. I have 2×6 decking on 2′ centers. I will be filling the joists with fiberglass insulation and covering the bottoms of the joists with 7/16 OSB. (The bottom of the joists are 7 feet off the ground at the high end and about 3 feet off the ground at the low end. My first questions are: Should I put a vapor barrier on top of the decking and underneath the plywood subfloor? What is the nail/screw pattern I should use on the 23/32 TIG plywood? We are in East Tennessee so it’s fairly humid here in the spring and summer and mostly mild in the winter (we’ll see 10 days of low teens, usual winter night is near freezing.)
Thanks
Replies
doesn't sound to promissing, hardwood in a space like that (not a warm floor) is going to buckle like crazy ...
The floor will have R30 insulation under it. The room will be space conditioned. My concern was more for moisture control
I would put a moisture barrier directly under the floor. Better yet, skip the fiberglass and move up to foam inuslation under the floor.
Mike HennessyPittsburgh, PA
that's not the point, the point is no matter what you do the floor will not be heated, it will be cold, a laminate would be much more stable
Let me summarize and make sure I understand your comments. Here's the whole flooring system as originally planned, from the bottom up: 7/16 OSB, 2x10 joists with r30 fiberglass insulation, 2x6 decking, 3/4 tongue-groove plywood, 15#felt, 3/4" finish floor. The original deck was screened in and roofed right after it was build 20+ years ago. The decking is in great shape. New windows/walls/outside door and a mini-split heat pump have been installed.
My original question concerned whether it would be better to put a vapor barrier between the decking and the 3/4 ply on top of it. A second question was the nail (or screw pattern) for the plywood on top of the decking.
With this, WANE's comment is that the floor will still be cold and subject the floor to too much temperature change--and an engineered floor would be a better choice. Is this a consensus answer?
Finally, what nail pattern should I use for the 3/4 TIG for either the solid wood or engineered flooring?
Thanks again. Mike
Poor Mike ..
hardwood contracts and swells with temperature (moisture). If this is being done in a room over an unconditioned space the temperature at the floor will be much different than the air 3' above it. Any hot air blown into the room will immediately rise, no matter how well the floor is insulated. If I were doing such a job I wouldn't use hwd, or inform the owner I couldn't guarantee the outcome, or use laminate or tile .. other's will weigh in, they usually do when someone takes a hard stance .. any way that's my story and I'm sticking to it!
Wane
"This is not a step."