Sealed grow shed insulation for underneath.

[B0731]

Best insulation for sealed grow shed underneath?

Shed is foamed and sealed with a mini split and co2 system. Floors are sealed with kilz and epoxy. Want to insulate under the building for the winter time. The foam gun would be hard to use at that angle so what are my best options ?

 

[xox]

should have insulated from above the floor system before sealing the floor, if you cant use the gun at that angle might be fucked. honestly id unscrew the subfloor and insulate then rescrew the subfloor then refinish it to be honest. did you screw plywood to the underside of the floor system so the spray foam or batts has something to sit on or stick to might be crawling underneath anyway

 

[B0731]

should have insulated from above the floor system before sealing the floor, if you cant use the gun at that angle might be fucked. honestly id unscrew the subfloor and insulate then rescrew the subfloor then refinish it to be honest. did you screw plywood to the underside of the floor system so the spray foam or batts has something to sit on or stick to might be crawling underneath anyway

There is no subfloor.. it’s an outdoor shed.. it’s just a piece of plywood flooring I’m assuming.

 

[B0731]

should have insulated from above the floor system before sealing the floor, if you cant use the gun at that angle might be fucked. honestly id unscrew the subfloor and insulate then rescrew the subfloor then refinish it to be honest. did you screw plywood to the underside of the floor system so the spray foam or batts has something to sit on or stick to might be crawling underneath anyway

Also there are batts(rafters) underneath but I assume the plywood above them is the same wood walking on in the building.

 

[bignugs68]

Sadly what's been mentioned(removing flooring) is kind of your only option. Granted a halfway deal might be sealing around the perimeter, but the center space would still need to breathe in some way.

Or, foam board on top your sealed floor, and place new plywood over that with the same finish treatment?

 

[Drop That Sound]

Crawl up under there and use some of the spray foam (or even a small spray can of great stuff) like an adhesive to hold up rigid foam panels you cut out to fit between the joists? As in, stuff or prop the panels up in there, and foam just around the edge of each panel to fill any gaps.

Also, add more panels to insulate the skirting going around too, if there is any..

 

[Drop That Sound]

If you decide to insulate right over top of the floor as is (and have to raise it all up and lose a few inches), might as well plumb or wire in a radiant floor system while your at it..

 

[bignugs68]

Crawl up under there and use some of the spray foam (or even a small spray can of great stuff) like an adhesive to hold up rigid foam panels you cut out to fit between the joists? As in, stuff or prop the panels up in there, and foam just around the edge of each panel to fill any gaps.

Also, add more panels to insulate the skirting going around too, if there is any..

Haha I def agree, commit to the mud!! And get your foam spray up in there! I assumed if it was in question it had no crawl space or close AF to the ground.

@OP honestly, doing it right is much better than the shortcuts mentioned. Even if it's too close to the ground, but not secured,anchored like crazy; jack that baby up, brace it with a 2x4 and/or a couple blocks under its edge and insulate!

 

[Fallguy111]

Is your shed anchored to the ground? If not, lay it on its side.

 

[Roguedawg]

Thick foam board laid on top of the floor with the thin sheet of ply wood on top of the foam board works good, thats for mild climate if you are in alaska or something disregard. Depends on your climate but if you can use air exchange instead of generating CO2 do it.

 

[Highway61]

Straw around the perimeter of your shed will do a lot to keep your floor warm in the winter. Or snow banked against the wall, if you have it. Or both.

I have a similar problem with an uninsulated shed floor and no easy way to get under to add insulation. I just fluff up some straw around the perimeter every fall and keep an extra straw bail dry and handy to fill in where needed over the winter. My floors stay warm all winter and I live in a very cold climate.

 

[Drop That Sound]

Is your shed anchored to the ground? If not, lay it on its side.

A couple of large jacks and a beam would probably work just as good, unless you live near an Amish community or have a fork lift..

Tilt one side atta time, giving you just enough extra room to spray. Just long as there isn't any plumbing or electrical conduits that interfere, etc.