If your home has a concrete tile roof you and you are having small stains in your ceiling, it means your underlayment paper is dried out, has cracked and is now leaking. When concrete tile roofs became popular in the Southwest in the early 80's, the standard then was tacking a single layer of 30lb black felt paper to the top of the roof, stapling in the wooden battens and then laying the tile on top of it.
Please note this product is sold in a minimum order of 100sf.