Increase R Value of Floor in workshop.

Mot

Hi,

I have a 12' x 18' workshop out back that I want to insulate so I can work out there year round. (Mid-Atlantic region). The Shop sits on a rock base with 4"x4"s "foundation" and 3/4" Plywood Rough Flooring.

Under the floor I have no access to (unless I remove the current floor) so I'm looking for how best I can add padding and perhaps vinyl over for much better insulation. Should I be looking at a reflective material on one side or perhaps both? Or just foam products?

I'm trying to keep the additional stackup as low as possible and will probably be using 5mm on the finished floor so if I can keep the stackup to around 1/2" I should be good...

Thanks!

Jamie Hall

Insulation is all about thickness or, in the case of infrared radiation, reflectivity. If all you have to play with is half an inch, and no infrared ... not much you can do. You could put a half inch layer of rigid foam in there, I suppose... but it isn't going to do much.

hot_rod

Mot said:

Hi, I have a 12' x 18' workshop out back that I want to insulate so I can work out there year round. (Mid-Atlantic region). The Shop sits on a rock base with 4"x4"s "foundation" and 3/4" Plywood Rough Flooring. Under the floor I have no access to (unless I remove the current floor) so I'm looking for how best I can add padding and perhaps vinyl over for much better insulation. Should I be looking at a reflective material on one side or perhaps both? Or just foam products? I'm trying to keep the additional stackup as low as possible and will probably be using 5mm on the finished floor so if I can keep the stackup to around 1/2" I should be good... Thanks!

Could you poke some holes every 18” in inject foam in?  That is how they do walks that are uninsulated without removing siding or sheetrock

any thermal break will help, even 1/2 foam board

gunn308

So as I understand you have 4x4s sitting on rock? call your local foam outfit and have them drill and plug your floor and put in 3 1/2 " of polyiso which will give you a minimum of R21 and no loss of headroom. The foam will also seal all drafts.

Larry Weingarten

Hi, Any chance you could trim the doors so that you can use something like two inch foam on the floor with plywood on top?

Yours, Larry

pecmsg

Just pull the sub floor and spray foam the entire underside. 

mattmia2

Insulating the perimeter above and below ground will help a fair bit.