How to Pour a Concrete Floor Over Insulated Foam Board
- 1). Spread base gravel evenly over the ground where you will be pouring the basement slab. Put down an inch less than you would normally do if you were not going to insulate the concrete floor.
- 2). Place across the leveled gravel a 1-inch layer of extruded polystyrene foam board. Cover the entire area where you will be pouring the concrete floor.
- 3). Tape all the joints of the foam board together using builder's tape. It is important that this insulation layer be tight to work effectively.
- 4). Place across the top of the foam boards you have taped together a layer of polyethylene sheets. Let it overlap each seam by 6 inches. Check for tears, holes or gaps and use the builder's tape to repair them. This will create a vapor barrier that will keep moisture from passing through.
- 5). Tape all the joints of the polyethylene sheets together using the builder's tape.
- 6). Pour cement over the top of this layer. The result will be an insulated cement slab that will keep cold from seeping through the floor.
