Mastic / Deck-O-Seal

What is it?

As seen in the picture above there is an expansion joint between the coping and deck. Mastic, commonly called Deck-O-Seal, is the elastomeric polymer that seals this joint from water intrusion.

Why is it there?

If this joint is not sealed water tight, it could cause the deck or coping to move up or down, or cause tiles to start popping off. This damage can be much more costly than replacing the mastic when it is cracked or seperating.

Protect your investment and keep your mastic in good shape!