The house I'm building is 24' x 48' on a crawl space with a trussed roof.
The floor has 2x8's for floor joists on 19.2" centers. The sub floor is 3/4" T&G Avantech sub floor panels. On top of the sub floor, I am planning to use solid bamboo snap together wood flooring throughout the entire house.
I originally planned to insulate the floor with cellulose by blowing it in from the crawl space after the sub floor is down, using the glue-on mesh made for that installation method. Then I would sheath the bottom of the joists with preforated pegboard followed by 1/4" hardware cloth for rodent prevention.
Now, I'm wondering if maybe I could just glue hard foam sheets over the sub floor and then the bamboo flooring over the foam.
It seems this would be a lot easier and simpler, but perhaps quite a bit more costly.
Would this be feasible ? And, if so:
What thickness of foam would equal the insulation value of 7.5" of cellulose ?
What kind of foam should I use; any suggested sources ?
And finally, would the foam need to be thick enough to where I would need to use a double bottom plate for the interior walls so that I would have something to nail the bottom of the drywall to ?
Or would it be feasible to just build the interior walls after the bamboo flooring is down (don't know how much that would interfere with the flooring's ability to 'float') ?
Thanks,
Arky
Another option is to sealed/insulate/warm the crawl space. This keeps the floor structure away from cool/wet zones. Makes floor penetrations less of a concern. Just another way to skin the proverbial feline.
What is the climate zone or state the building will be in? Climate can make a difference as to what works best or what is needed.
Quote from: MountainDon on December 24, 2010, 11:03:25 AM
What is the climate zone or state the building will be in? Climate can make a difference as to what works best or what is needed.
Central/western Arkansas
Thanks, and pardon my ignorance, but is the structure already built or is this a question in the design stage. (There is so much going on I loose track of what's what at times. Sorry.)
Quote from: MountainDon on December 24, 2010, 02:18:45 PM
Thanks, and pardon my ignorance, but is the structure already built or is this a question in the design stage. (There is so much going on I loose track of what's what at times. Sorry.)
Pier/post foundation done, floor joists done (subfloor will go on after roof is on), exterior walls done, in process of setting trusses.
I'm not sure but I believe being in what is classed as a mixed humid climate complicates this.
I wonder if the rigid foam board could be applied to the underside of the floor joists and the seams sealed with tape or foam compatible caulk? I believe I've seen this someplace (building science?) but can not put my finger on it. I think the joist bays were left empty, not filled with anything. And I think the rim joists were insulated with foam as well.
The ideal insulation is likely something like sprayed on closed cell foam at least 2 inches thick against the underside of the subfloor and joists. ???
Try searching the buildingscience website for methods to insulate a raised floor in a mixed humid climate.
I had thought of doing rigid foam board on top of the subfloor with cement board then porcelain tile for our cabin. I didn't like the extra thick bottom wall plates, or whatever, that would be needed to secure drywall etc around the floor. It still has some appeal.... ???
We have rigid 1" foam board screwed to the joists and batt insulation in the joist cavaties. My location is is similair to the Arky OK/AR border.
Are you on piers or have a typical crawl space area? If possible I would have foam sprayed at the subfloor level if on piers or spray foam on the concrete block foundation. Only way to go in my opinion.
Grouseman
I'm in the process of insulating my walls, 2 x 6 infills for post and beam on 16" centers and I am using 3" closed cell foam board to insulate. The short story is that I secured a bunch of vented nailboard at auction which is 4 x 8 sheets of 3" foam with 7/16 OSB stapled to furring strips that are glued to the foam which has firberglass cloth on both sides. I used them on the roof and had extra so am separating the osb from the foam and using the foam for insulation. It is easy to cut on a tablesaw although a jobsite saw will not raise the trunnion high enough to cut all the way through where a good 10" tablesaw would do so. It is remarkably easy to rip them into strips which will fit so snugly that caulking doesn't appear neccessary. If used on floor joists, I would cut some furring strips to act as cleats and air nail them in to hold the foam tight. No worry about moisture, I would do it in an instant. In my location, N. IL. there are two factory seconds foam distributors and I would suspect there may be some in your area also. Truly worth considering.