Deck Accessories
Protection
Trex
$15-$45/roll

Deck Joist Tape for Substructure Protection

Deck joist tape is a self-adhesive butyl membrane that protects the tops of deck joists from water damage caused by moisture entering through fastener holes and gaps between deck boards. This protective barrier prevents the primary cause of deck structural failure extending substructure life by years.

Key Features

  • Self-adhesive butyl membrane
  • Seals around screw penetrations
  • Prevents joist rot
  • Easy peel-and-stick
  • UV resistant for exposure
  • Extends structural lifespan

Specifications

Width: 1-5/8 to 3-1/8 in | Material: butyl rubber | Self-sealing: yes around fasteners | UV rated: 6 months exposure | Application: peel and stick | Temperature: apply above 40F

Best For

All deck joist tops beam caps and any structural deck member where water penetration from above can cause rot and deterioration.

Compatible Materials

Pressure-treated joists
Cedar beams
LVL engineered lumber
Steel joists
Rim joists

Pros & Cons

Pros

  • ✓ Dramatically extends joist life
  • ✓ Self-seals around screws
  • ✓ Easy application
  • ✓ Prevents primary deck failure
  • ✓ Affordable structural protection

Cons

  • ✗ Must apply before decking
  • ✗ Adds project cost
  • ✗ Can be slippery when wet
  • ✗ Temperature affects adhesion
  • ✗ Some brands hard to work with

Installation Tips

Apply to clean dry joist tops starting at one end. Press firmly along entire length. Overlap splices by 3 inches minimum. Extend tape over beam connections. Do not stretch during application. Install decking within 6 months of application.

Frequently Asked Questions