Apply Joist Protection/Waterproofing

What happens here

Once the dadoes are cut and cleaned, and the fit is confirmed, apply a protective waterproofing membrane or joist tape to the top surface of the joists, especially over the newly cut areas. Use a small paint roller to evenly spread the dark, thick liquid membrane. This step protects the wood from moisture intrusion, which can lead to rot and premature deterioration, extending the lifespan of the deck frame.

Goal: Protect joists from moisture with a waterproofing membrane