1.   Can shingles be applied over it?

2.   If the shingles were applied directly to the sheathing, they would decay long before their time.

3.   Q. I am applying shingles to the walls of a shed.

4.   Roofing shingles are applied over the shield.

5.   The leaks under the windows may mean that shingles were not applied properly under the outside window sills.