To attach the insulation you can use screws with large washers a special adhesive made for adhering foam board insulation or for smaller pieces you can seal them in with caulk or spray foam.
How to insulation attic foam boards.
Select rigid foam insulation boards that are at least 1 2 inch less in thickness than the rafter space is deep if you plan to finish the attic as living space.
Foam insulation boards can be attached to concrete walls as well and in such a case care should be taken not to chip the cement.
But insulating your floors is a good idea for many reasons including energy efficiency and height adjustments.
Use a chalk line or t square to mark where it needs to be cut.
How do you install rigid foam board.
You can use a utility knife to cut using the same cut and snap process you use with drywall.
Most people do not think about insulating their floors unless perhaps it s their attic floor.
A table saw will also cut the board but it.
Foam board insulation is easy to cut with a circular saw with a masonry blade or scored with a utility knife and snapped like you would drywall.
Remove any existing pieces of insulation that might have been covering the attic walls until now.
2 measure and cut the foam boards as.
Step 2 install insulation boards.