The One Deck Upgrade You Don’t Want to Skip – Joist Tape
When planning a custom deck, most homeowners focus on the visible features—deck boards, railings, and lighting. One often-missed upgrade can significantly extend the life of your deck and protect your investment for years to come. Joist tape is one of the most affordable upgrades you can make—and one of the most important.
What Is Joist Tape?
Joist tape is a waterproof, adhesive membrane applied to the tops of deck joists, beams, and ledger boards before installing deck boards. Typically made from butyl rubber, asphalt or polyethylene, it provides a waterproof barrier to prevent moisture from penetrating the wood. It’s a simple, effective way to extend the life of your deck, reduce maintenance, and ensure long-term performance. If you’re planning a new deck or upgrading an existing one, it’s a small detail that makes a big difference.
How Joist Tape Protects Your Deck
Water is the number one enemy of any outdoor structure. When water gets trapped between deck boards and joists, it accelerates:
- Wood rot
- Mold and mildew growth
- Structural weakening
- Fastener corrosion
Joist tape prevents water penetration by sealing the top surface of the framing lumbar, stopping water from soaking into the wood and causing rot.
Extends Structural Lifespan: By reducing moisture exposure, joist tape helps preserve the integrity of your deck’s substructure—often adding years to its life.
Protects Fasteners: Metal fasteners are vulnerable to corrosion when exposed to moisture. Joist tape acts as a barrier, helping prevent premature rust and failure.
Reduces Maintenance Costs: A small upfront investment in joist tape can save you from costly repairs or even full deck replacement down the road.
A Small Cost with Big Returns
Compared to the total cost of building a deck, joist tape is relatively inexpensive. Yet it protects one of the most critical—and costly—parts of the structure: the framing. Think of it as insurance for your deck. You may not see it, but you’ll definitely benefit from it over time.
A custom deck is an investment in your home and your lifestyle. Protecting that investment means looking beyond surface-level features and addressing the structural elements that keep your outdoor structure safe and secure.
Ideal for New Builds and Resurfaced Decks
Joist tape is typically applied during initial construction, but it can also be used when replacing deck boards on an existing frame. If your substructure is still in good condition, adding joist tape during a resurfacing project is a smart upgrade to extend your deck frame’s lifespan.
When getting a quote for a custom deck project, be sure to ask your deck builder about joist tape.
FAQs
What does joist tape do on a deck?
Joist tape creates a waterproof barrier on top of deck joists, beams, and ledger boards to help prevent moisture from penetrating the wood frame.
Is joist tape really necessary?
While not always required by building code, joist tape is highly recommended to extend the lifespan of your deck framing and reduce the risk of costly structural repairs caused by trapped moisture.
Can joist tape be added to an existing deck?
Yes. Joist tape can be installed during a deck resurfacing project when old deck boards are removed and the existing framing is still structurally sound.
Does joist tape help protect deck screws and fasteners?
Yes. Joist tape helps reduce moisture around screws and fasteners, which can help prevent rust, corrosion, and premature fastener failure.
Is joist tape worth the cost?
Yes. Joist tape is one of the most cost-effective deck upgrades. It is relatively inexpensive compared to the overall cost of a deck build and can add years to the lifespan of your deck.
