Wood Preservatives: How to Stop Rot Before It Starts

Protecting your wood framing is crucial. Learn about the chemical preservatives and butyl tapes that prevent joist decay under your composite decking.

Many homeowners spend thousands of dollars on highly resilient luxury composite deck boards, but completely ignore the structural skeleton underneath them. Because Trex and TimberTech boards can last 50 years, the pressure-treated pine joists underneath them are often the first thing to fail. Here is how you protect them.

The Threat of Standing Water

When a screw is driven through a deck board and into the joist below, it creates a microscopic puncture hole in the wood. Over thousands of rainstorms, water seeps directly into these holes. Because the space between the joists is narrow and shaded from the sun, the water never evaporates. This leads to aggressive, rapid wood rot.

The Butyl Tape Solution

At Loudoun Decks, we deploy a crucial protective layer called joist tape. Before any surface boards are installed, we roll a thick layer of self-sealing butyl tape across the top ridge of every single joist and beam.

When a screw is driven down, the butyl tape physically stretches and seals around the thread of the screw, permanently preventing water from entering the wood framing. It is an incredibly inexpensive preventative measure that adds decades to the structural life of your deck.