4" x 75' Waterproof Membrane Joist Guard/Black Deck Tape Roll

This product provides waterproof protection for joists that prevents rotting of structural timber under exterior floors, such as decks and balconies. It is a self-adhesive membrane composed of elastomeric bitumen. The surface is made of polyethylene, the underside is covered with a silicone release film.

Features:

• Self-sealing around screws and nails
• Substantially extends the service life of patios at low cost
• Barely visible between the boards