Deck Joist Tape
Deck joist tape is a self-adhering butyl strip capped over a joist before the boards go down. It earns its place because of what the fastener does, not the rain.
Every screw is a hole in the wood. Trex states its butyl tape self-seals around deck fasteners, so water crosses the joist instead of soaking down the screw. The 2021 IRC model code does not call for tape. This is manufacturer practice, and local rules vary.
Width follows the member: narrow for a single joist, wider for a doubled beam. In stock.
