Joist tape (double-joist) applied to top of deck understructure

Joist tape (double-joist) being applied to deck joists

Joist tape (single-joist) applied to top of deck understructure

Joist & Flashing Tape

Sizes: 1-5/8" x 50' (Single-Joist)

1-5/8" x 50' (Single-Joist) 3-1/8" x 50' (Double-Joist/Beam)

Color: Black

Black

Product variants

Maximize the life of your deck substructure with deck joist flashing tape. Whether your deck foundation is made from wood or a composite material, flashing tape helps protect the top and edges of the joists from moisture and water damage.

Available Options

1-5/8" x 50' (Single-Joist) in Black
3-1/8" x 50' (Double-Joist/Beam) in Black

Product Details

Can be applied to the top of joists, rim joists, and ledgers to protect wood against water damage
Increases the holding power of deck screws
Acts as a barrier to protect screw holes from moisture and rot
We recommend using ProWood® professional grade treated lumber for the understructure

Find Joist & Flashing Tape installation details below or visit our Installation Instructions page for a more comprehensive list of installation instructions.

Joist & Flashing Tape Installation Instructions English French Spanish

Find Joist & Flashing Tape answers here, or visit our frequently asked questions page for answers to more general questions.

What would you recommend using for the understructure of a deck?

We recommend using ProWood® professional-grade treated lumber when building the understructure for your deck. ProWood pressure-treated lumber is made for ground contact and backed by a Lifetime Limited Warranty against termite infestation and rot.

Can I fasten Deckorators decking over an existing deck, balcony, or porch?

Composite decking is intended to be installed directly to the structural joists. DO NOT fasten to the top of old existing deck planks or balcony and porch floors.

Can I put Deckorators decking over a concrete patio?

Yes. For this application, we recommend using the Deckorators Sleeper system as support beneath the deck boards in conjunction with our mineral-based composite decking. Arrange the sleepers on the existing patio and install decking.

If using wood-plastic composite, we recommend 2x6 boards standing vertically on edge as support joists over the concrete. Next, fasten the decking to the support joists.

Be sure to allow a ¼" gap between the long edges of the deck boards. Drainage and ventilation are necessary for best product performance. To level the deck, we recommend shims that allow a clear 2" space between the bottom edge of the joists and the concrete. You’ll need to check with your local building code agency on foundation footing requirements. See the installation instructions for full details.

How much space is recommended for proper ventilation underneath a deck?

A clear 2" space between the bottom edge of the joists and the grade is recommended to allow proper ventilation. We recommend using ProWood® professional-grade treated lumber when building the understructure for your deck. ProWood pressure-treated lumber is made for ground contact and backed by a Lifetime Limited Warranty against termite infestation and rot.

Visit our Warranty page to view our warranty documents.

Visit our Technical Information page to view our technical documents.