If you’re building or repairing a deck, you’ve likely wondered: Can you use aluminum flashing with pressure-treated lumber? The short answer is yes—but with some important caveats to ensure longevity and safety.
At Advantage Lumber, we get this question a lot, especially from homeowners and builders focusing on ledger flashing. The ledger board, which attaches the deck to your home, is the most common failure point on a deck. Improper installation or protection here can lead to serious issues down the line.
Why the Ledger Matters: Shocking Statistics on Deck Failures
Deck ledgers are critical because they bear much of the structural load. According to the North American Deck and Railing Association (NADRA), an estimated 90% of deck collapses result from ledger board connection failures.
This isn’t just a minor concern—between 2000 and 2008, there were at least 30 reported deaths from deck failures, highlighting the real risks involved. Water intrusion, corrosion, and inadequate fastening are often the culprits, making proper flashing and protection essential to prevent rot, structural weakening, and potential collapse.
The Concern with Aluminum and Pressure-Treated Lumber
Pressure-treated lumber is infused with chemicals like alkaline copper quaternary (ACQ) or copper azole (CA) to resist rot and insects. However, these copper-based preservatives can react with aluminum, causing galvanic corrosion over time if they’re in direct contact.
This corrosion eats away at the aluminum, compromising its effectiveness as a moisture barrier. That’s why direct application of aluminum flashing on pressure-treated wood isn’t recommended without a protective layer.
Advantage Lumber’s Recommendation: Start with DeckWise Ledger Tape
To safely use aluminum flashing (or even skip it altogether), we at Advantage Lumber strongly recommend applying DeckWise ledger tape first. This self-adhesive tape creates a waterproof seal over the ledger board, joists, and other critical areas. Here’s why it’s a game-changer:
- Extra Layer of Protection: The tape blocks moisture from penetrating the wood, reducing the risk of rot and extending your deck’s lifespan.
- Corrosion Prevention: By acting as a barrier between the pressure-treated chemicals and aluminum, it prevents that unwanted chemical reaction, allowing you to add aluminum flashing on top if desired.
- Flexible Options for Homeowners: Many choose to use just the ledger tape without any aluminum flashing—and that’s perfectly fine! It’s an approved method that provides robust protection on its own. However, if you’re looking for an added layer of security, applying aluminum flashing over the tape is a great way to double down on durability.
Installing DeckWise ledger tape is straightforward: Clean the surface, peel and stick, and ensure full coverage. It’s compatible with most decking materials and holds up well in various weather conditions.
Final Thoughts
Whether you’re a DIY enthusiast or a professional builder, protecting your deck’s ledger is non-negotiable for safety and longevity. By using DeckWise ledger tape—available through Advantage Lumber—you can confidently incorporate aluminum flashing if needed, or rely on the tape alone for reliable performance. If you have more questions about deck building materials or need supplies, reach out to our team at AdvantageLumber.com. Let’s build decks that last!