To prevent structural degradation of deck joists, when laying your deck foundation (substructure) choose a good joist tape to help prevent the rot. Water that accumulates under the decking boards cannot dry out easily. It can remain trapped for a long time, creating perfect conditions for rot and decay.
DECK FLASH BARRIER is a flexible polyethylene waterproof flashing and barrier material, with a rubberized asphalt mastic adhesive. Deck flash barrier is intended for joist, post and ledger board protection. It creates a physical barrier that prevents the corrosion wood and metal surfaces.