Can you insulate over plywood in attic?

Re: Attic Insulation Over Plywood Floor? I agree that as long as the insulation under the plywood is tight to the bottom of the plywood that laying additional insulation on top should be fine. The plywood should add a little insulating value itself.

Can you put insulation on top of plywood?

When you need to insulate plywood sheets, stay away from common fiberglass batt insulation. Rigid foam insulation comes in sheets that you can cut to fit your plywood and it adheres easily, making it a better choice for insulating your plywood.

Does my attic need a vapor barrier?

All attics — vented or unvented — should have an air barrier (a properly detailed airtight drywall ceiling, for example) regardless of climate. Omitting a ceiling vapor barrier by arguing that “you have to let the moisture escape” or “because the house has to breathe out the top” is actually correct, in a way.

How do you remove old plywood from floor?

One method is to use a small hole saw and drill around the nails, just the thickness of the floor. Then (after getting the sheet of plywood up) you end up with a bunch of small plywood plugs you can break off the screws/nails fairly easily, and enough nail/screw to get a grip on for removal.

How do you insulate a plywood shed?

To insulate a shed floor you can lay a thin layer of insulation board over the top of the existing flooring and top it off with plywood to stabilise the floor surface and to protect it. Again, making sure that you seal any gaps with a good sealant.

What is the R value of plywood?

1.25
Tables of Building Material R-values

How thick should attic floor be?

You need 3/4-inch plywood. The thinner plywood is acceptable when the joist spacing is 16 inches. If you plan to finish the floor in the attic and turn the room into a living space, however, you should always use 3/4-inch plywood.