Spray foam using spray foam would be an excellent option.
Ceiling foam board insulation installation.
Cut the rigid insulation.
It will degrade its r value.
In that situation the foam would be sprayed directly to the backside of the roof sheathing resulting in an un vented roof.
All foam boards absorb water vapor.
Press the cut.
Use closed cell spray foam closed cell foam board extruded polystyrene such as dow styrofoam or foil faced iso board.
The best way to install foam board insulation under drywall is to frame the wall with 2x3 inch lumber for the top and bottom plates and 2x2 inch lumber for the studs.
Because foam board insulation is flammable building codes require it to be covered with fire resistant paneling or drywall.
Garage ceiling and insulation rigid foam board install with pictures i searched high and low for ideas on the best way to finish my garage so it would retain heat.
Seal the insulation or the ceiling surface below against air leakage.
Do no use a vapor barrier under the insulation.
It took a lot of time to come up with what i did so i wanted to give back to the community and show what i did.
Foam board insulation is easy to use and is a great diy way to add some insulation.
Lay the panel on a scrap of plywood or a subfloor that won t be marred by the knife blade.
It comes in standard size 4 8 sheets and smaller sizes in many different thicknesses from 1 4 inch to 2 inches.
Cover the insulation with a vapor barrier before you install it.
When installing the foam use caulk or tape for maximum insulation between the material and the board or floor.
Obviously on a project like this there are quite a few options with varying costs and benefits.
Find ceiling foam board insulation at lowe s today.
Measure between the joists or rafters which are likely to be 16 22 or 24 inches on center.
Keep foam board insulation away from direct sunlight prior to installation.
Feasible insulating options include.
Some types of thicker foam board insulation are available but they may need to be special ordered.