Best way to insulate supended floor ???
AnthonyPannolino
| Posted in Construction Techniques on
Question:
What is the best way to insulate a suspended floor with ground clearance issues on the underside.
Note: This cottage we are building is on an island, so getting a spray foam insulation truck over to the island is almost impossible. I have been looking at structural-insulated-panels but I would like to know if there is anything better or if I could make my own insulated panels in-between the joists.
Replies
you have a double thread ... delete one of them
which one do you want answered? This one or 105724.1 ?
Sorry, I thought I had problems posting the first message. Both postings are the same but you can answer the latest. Thank you for the help!
Seal the crawl put plastic down on the ground and rigid foam on the foundation walls covered in Drywall for fire protection. Drop a heat run into it and treat if like a really short basement.
Thank me later.
For the foundation we are using concrete block piers. At some points on the island we will have 2'-4' feet of clearance where we can fit underneath the structure, insulate, typar, and cover with plywood . At other locations of the building there is only about 16"-24" inches of clearance so access underneath is a problem. Do you know of a system or an efficient way to insulate the floor from above since we can't get underneath the structure?
I guess I should have asked this first. Where's the island? Maine, The Bahamas? If you're in a warm climate then dont use my plan, but in a cold climate (are there pipes under there?) I would seal the crawl.
The island is located in Georgian Bay in Ontario, Canada.
Is it possible to get a layer of plywood on the underside of the joists? If so, you could cut holes in the subfloor and dense pack cellulose in there.
No, that's the problem, in some areas we will not be able to get underneath the structure. Its a new cottage we are building on a island on Georgian Bay in Ontario Canada. Since it is new, we will have access to joists from above but will be unable to get underneath to install plywood.
Then as another poster suggested, you'll have to fasten stops on the bottom edge of the joists, and drop in rips of plywood or foam. If you were using I joists, you could use the bottom flange as stops and eliminate the step of fastening stops at the bottom edge of the joists. Floors are difficult to insulate well. You might consider an additional step of adding another layer of foam on the top. I recently did this. Sheathed with 5/8 OSB, then a two inch layer of foam, then screwed a second layer of 3x4 inch plywood on top of that, using long screws.
Do you know of a system or an efficient way to insulate the floor from above since we can't get underneath the structure?
2-part urethane foam is available in moderately sized kits which you can purchase and transport to the island yourself in whatever boat you are using to haul your materials. The kits are not cheap, but they are almost certainly cheaper than what it would cost to get a foam truck onto a barge and have a tugboat tow it over to the island for you.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
That's great, Thank you!
I didn't know kits like this were available. I will check online to see if I can get them in Ontario Canada. Thank you for your help.
Anthony,I've done this a couple of ways. I've skinned over the bottom of the joists with 2" foil-faced polyiso board fastened from below with big washers and screws, then drilled holes in the rim joist and blown cellulose. When access is limited to from above, I've put cleats on the sides of the joists, laid 2" polyiso board on the cleats, then blown cells through the subfloor. You could use plywood instead of foam, But I figure you are buying sheet goods, you might as well buy some with R-value to boot. Don't use anything thinner than 2" though, to resist the force of the cells being blown in.Steve