Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Increase R Value of Floor in workshop.

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!

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,696
    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.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 23,224
    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
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • gunn308
    gunn308 Member Posts: 12
    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
    Larry Weingarten Member Posts: 3,576
    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
    MikeAmann
  • pecmsg
    pecmsg Member Posts: 5,271
    Just pull the sub floor and spray foam the entire underside. 
  • mattmia2
    mattmia2 Member Posts: 10,819
    Insulating the perimeter above and below ground will help a fair bit.
    pecmsg