Shed modifications?

[rcp612]

I know some of you guys have your shop in a backyard shed. I'm going to be doing the same this summer and am wondering about insulation.
The walls and ceiling area don't really concern me, it's the floor I'm worried about. Does anyone have their floors insulated? Would it work, or just provide housing for the mice and other creatures?
Living in the central Ohio area doesn't help since the weather changes almost hourly but, I'm stuck with no other choice.
I am planning to weatherstrip the door and possibly install an extra layer of 3/4" t&g plywood on the floor but, I want to be able to use this year round (with some exceptions) and, most importantly, provide suitable protection for my tools from rust and general temperature related problems.
Any suggestions, other than moving to a better climate would be greatly appreciated.

[dbhost]

I had considered the same thing, due to heat gain here in Texas, and the consensus was pretty much, it's not worth it. Of course I was talking skid on gravel bed foundation...

Now if you are on pier & beam it might be worth considering...

I would still think that insulating batts would provide a wonderful, warm and cozy winter home for rats, field mice and other undesireable tenants.

I think about the best you could hope for is maybe sandwich some foam board, and then another layer of plywood, maybe... Of course now that I see that typed out it looks pretty dumb...

[jackellis]

You don't say whether this shed is in place or whether you're planning to build or install one.

It depends on how much money you want to spend. Batts are pretty worthless for insulation unless they are installed very carefully, and most people don't bother to install them correctly.

We're using a blown-in insulation product in our new home that is packed pretty tightly into the stud bays. Pricier than batts, but it eliminates the voids critters can live in and is almost as good as spray foam. If money is no object, spray foam is the best insulation available IMHO.

It sounds like you're not going to put the shed on a slab but if you were, I'd suggest 1-2" of foam board under the slab and around the edges.

Another thing you can do if the shed framing is exposed is seal all of the gaps with spray foam. Buildings lose a surprising amount of heat through infiltration. Housewrap helps but if you can seal all of the many tiny openings where air can get in, it helps a lot. Be careful with foam around window and door frames because foam expands with enough force to warp the frames and affect the way the windows and doors operate.

[Mr__Bill]

I think about the best you could hope for is maybe sandwich some foam board, and then another layer of plywood, maybe... Of course now that I see that typed out it looks pretty dumb...

Not really.
Some treated ply on the bottom, under the floor joists and a vapor barrier over the joists and under the flooring plywood should make a great deal of difference on your feet in the winter. I would however do some insulation in the walls and certainly under the roof. You will find the insulated roof makes a great difference on a sunny summer day.

Bill, on the Sunny Oregon Coast

[LarryG]

I'm wrestling with the same question right now, for the wood-floored shop building I have on the drawing board. (Well ... on the CAD screen, actually.)

Warm will always migrate to cold so floor insulation can be worth doing, although as Bill says the ceiling is the first priority, followed by the walls. If the building is over a full crawl space, the floor could be insulated with batt insulation without too much concern for the critters. The vapor barrier should be near the warm side, or top, which means that over time the insulation material can sag and separate due to gravity. You can apply chicken wire or insulation netting over the bottom of the joists, but this is most effective only when you insulate the full depth of the joists.

If the building is on skids, you'd probably be better off to not try to use batt insulation at all.

What Dave (dbhost) typed out is not dumb at all. A layer of rigid insulation between two layers of sheathing is sometimes done in shops, especially ones on existing slabs, and is a good solution if you can stand the loss of headroom. Sleepers, either 2x2s or 2x4s laid flat, should be nailed down at 16" OC, a 1-1/2" thick layer of high-density foam insulation board then fitted between them, and finally a layer of plywood applied. (Is this a new building? If so, compensate for the foam thickness by adding a second plate to the bottoms of the walls; this allows you to use standard pre-cut studs.) I'm leaning toward this system for my new building, although it would likely be something I won't add until some time in future.

[pelligrini]

I've never really considered insulating my floor, doesn't exactly get all that cold here.

One thing I wanted to point out, especially if building on skids; beef up the floor framing. If at all possible, have foundation support under the exterior walls.

My old shed is on skids. Between the bugs, rot & age my floor is sagging around all the exterior walls. The floor joists are bending and crushing at the 4x4 skids. I finished up my workbench base and when I moved it into place it was rocking terribly. After I got done cussing myself for a while I had to apologize. It wasn't the workbench, it was the floor.

It might have to something to do with the couple tons of stuff hanging on the walls & stored above.

[dbhost]

Perish the thought!

Hate to admit it, with LOML's unemployment dragging on, we are having to seriously rethink the shed / shop idea... It is now her idea, and plan for me to keep the shop in the garage until the $$ gets better...

I might have to start selling workshop output to pay for the workshop I want...

At least I have almost all the equipment I wanted... Just short of pnuematics now... From there out it is upgrading, or bits and pieces stuff...

[rcp612]

Thanks to all for more considerations on my part.
It will be a purchased unit set on concrete and fully insulated walls and ceiling.
Maybe I'm just over thinking this.....
Any way, thanks for the suggestions.

[LarryG]

It will be a purchased unit set on concrete and fully insulated walls and ceiling.
Maybe I'm just over thinking this.....

I don't think you're over-thinking it at all. When you mentioned a layer of plywood, I presumed a wooden floor structure. A concrete slab, coupled with your climate, adds up to several good reasons to insulate the floor. The concrete will retain cold, and moisture. It will be hard on your legs and feet, and unforgiving to dropped tools.

Your initial idea of putting down a layer of 3/4" plywood, over the wood sleepers and rigid insulation that I suggested, would IMO be well worth doing if you intend to work in the shed year-round.

[dbhost]

Not sure where Howard is, but if it's anywhere near that lake... You are gonna need all the insulation you can get...

Even here in coastal TX, concrete slab floors suck heat like a magnet. You WILL want to use the concrete slab as a sub floor, and use a packed / insulated raised type floor of some sort for all the reasons LarryG mentioned. Another one not mentioned is noise. Concrete lets sound bounce around like crazy, so every little noise is just that much more irritating.

[master53yoda]

In housing once you have insulated the roof and the walls in most cases insulating the floor will do more good heat loss wise then double panning windows will do. I would use foam panels enough to give at least R 7 or 8 you will be surprised how much difference it will make. fiberglass would be cheaper but then you will need to consider the critters nesting in it