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WiseWrap® JoistTape™
WiseWrap® JoistTape™ is a flexible polyethylene waterproof flashing tape with rubberized asphalt mastic adhesive. Apply to the tops of deck joists, over ledger boards, and around support posts to create a durable waterproof barrier that prevents wood rot and decay. The self-sealing "Super Grip" adhesive seals around deck screws as they penetrate, blocking the primary pathway for water infiltration. Each roll measures 3" wide x 75' long at 35-40 mil thickness—enough for approximately 25 linear feet of double joist or 75 feet of single joist coverage. Prevents the moisture damage that shortens deck framing life. Also creates a barrier between ACQ/CA-B treated lumber and metal hardware to prevent galvanic corrosion. Should not be exposed to direct sunlight for more than 90 days.
Available Options
Choose your preferred options and quantity below.
3" Asphalt
1 Roll
JT-3x75
3" x 75' •
$29.99
per unit
Why Choose Joist Protection?
How Joist Tape Prevents Deck Rot
Clean the Joist Tops
Brush off sawdust, dirt, and moisture from every joist surface. The tape bonds best to clean, dry wood — even pressure-treated lumber benefits.
Roll Out the Tape
Unroll the self-adhering butyl tape along the top of each joist. Press firmly as you go. Overlap seams by at least 2″ to prevent water wicking between layers.
Seal the Ledger
The ledger board connection is the single most failure-prone joint on any deck. Apply ledger flashing tape from the top of the ledger down and over the face, lapping onto the house wrap.
Fasten Through the Tape
When you drive screws or nails through joist tape, the butyl compound self-seals around each penetration — maintaining the waterproof barrier even at fastener points.
Pro Tip from Our Deck Specialists
Even pressure-treated joists rot at the top surface where water pools under decking. Joist tape is cheap insurance that can add a decade or more to your substructure life.
Joist Protection — Common Questions
Frequently Bought Together
Accessories that pair well with joist protection for a complete installation.
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