Treated lumber is a popular building material that plays a key role in the construction of many structures in the Pacific Northwest. Our good friend Dennis McWhirter is an expert on pressure-treated wood, with nearly three decades of experience in the industry. In this series, Dennis provides answers to some common questions, and reminds us why treating lumber is one of the best things we can do to help preserve our greatest renewable resource.

The age-old question with treated lumber is: How long will it last? In today’s video, Dennis sheds light on that question. Here’s a recap of our conversation:

How long will pressure-treated lumber last outside?

Back in 1961, two wood scientists planted treated-lumber posts in the ground of southern Mississippi. Sixty years later, most of those posts are still there—no rot, no fungi, no termites. Their experiment set the official statistical lifespan of treated lumber that the industry refers to today: over 60 years. 

Of course, it’s important to consider the factors that can affect the lifespan and performance of pressure-treated lumber: drainage, maintenance, proper application, and sun exposure. 

How long is the warranty period for pressure-treated lumber?

All of our treated lumber products come with a lifetime warranty. The warranty will stay intact so long as the specific product is used as intended and any field cuts are sealed with end cut solution. Other suppliers may have different warranty periods or stipulations depending on the application of the lumber. 

Typically, the warranty is to the original owner of the pressure-treated lumber—unless you’re working with a contractor. In that case, the contractor can transfer the warranty over to the homeowner after construction is done.

Dennis is a wellspring of information on treated lumber, and we hope that sharing his knowledge will help you decide if pressure-treated lumber is right for your project. To learn more about pressure-treated lumber, check out how to maintain the lifetime warranty of pressure-treated lumber and this article on the difference between professional- and premium-grade lumber.