Skip to Content

Thriving Yard is an affiliate for companies including Amazon Associates and earns a commission on qualifying purchases.

Are Landscape Timbers Rated for Ground Contact?

Are Landscape Timbers Rated for Ground Contact?

Share Or Save For Later

Willie Moore
Latest posts by Willie Moore (see all)

Landscape timbers look great and are affordable, making them popular with homeowners. If you’re one of those homeowners, you may wonder whether these timbers are rated for ground contact.

Landscape timbers are rated for ground contact, which means they can be in direct contact with the ground without rotting. This is because landscape timbers are treated with a chemical that prevents them from decaying. 

I’ll further explain landscape timbers and how they work in this article. So if you’re planning on using landscape timbers for your next project, read on to learn more.

Importance of Rating Timbers for Ground Contact

Landscape timbers must be rated for ground contact. This means they’re treated to help them last longer. Otherwise, they’d rot and decay over time.

Landscape timbers are a versatile and attractive way to add structure and visual interest to your landscaping. However, selecting the right type of timber for your project is important.

According to the American Wood Protection Association (AWPA), you should choose treated landscape timbers for:

  • All projects involving ground contact
  • Projects that are difficult to maintain such as freshwater dock & posts (source).

Pressure-treated lumber is a good option for ground contact, as it’s treated with chemicals that help resist rot and insect damage. Cedar and redwood are also good choices, as these materials naturally resist rot and decay. 

How Landscape Timbers Are Treated

Landscape timbers are treated with various chemicals to extend their lifespan and prevent rot. The most common wood preservative used is chromated copper arsenate or CCA (source). CCA-treated timbers are often used in outdoor construction projects to resist rot and insect damage. 

However, CCA can harm humans and the environment, so it’s important to handle it carefully (source).

If you’re looking for a safer and eco-friendly option, go for landscape timbers treated with acetic acid or borate. These chemicals are less harmful to the environment and are still effective at preventing rot and protecting against insect damage.

When selecting landscape timbers for your project, ask about how they were treated so you can choose the right option before you purchase.

Alternatively, you can treat your own lumber. You can buy something like the Rust-Oleum 1904A Wolman (Woodlife) CopperCoat Green Wood Preservative (link to Amazon). It contains insecticide and fungicide, ensuring that your wood lasts as long as it should. Although your wood will have a greenish tint, it’ll go away with time.  

Debate around the Treatment of Timbers

Landscape timbers are essential to many landscaping projects, but there’s debate surrounding their treatment. Some experts recommend treating the timbers with a preservative to help extend their lifespan. Others say that not only is this unnecessary, but it can also damage the wood (source).

The truth is that there’s no definitive answer, and the best course of action depends on the specific timber and its intended use.

Use of Landscape Timbers Rated for Ground Contact

Rated landscape timbers can be used for a variety of projects, such as:

Building Fences

While there are many different fencing materials available, landscape timbers have a unique look that can enhance your home’s aesthetic. The treated ones are ideal for this purpose as they can withstand the elements and last for many years. Landscape timbers are also relatively inexpensive and easy to work with, making them a great option for do-it-yourselfers.

Of course, before you start any fencing project, you must should with your local building code to ensure you’re following all the necessary regulations. Once you’ve got the green light, building a fence with landscape timbers is relatively simple.

Constructing Raised Garden Bed

Landscape timbers are an excellent material for constructing raised garden beds. They’re durable and weather-resistant, making them ideal for withstanding the elements. Raised garden beds also make it easier to control the type of soil and amendments in your plants. In addition, they’re easy to work with and can be cut to your desired size.

See our guide on 7 Best Wood Options For Raised Gardens (And 3 To Avoid).

Designing a Treehouse

A treehouse is a great way to add extra living space to your property. And what could be more fun than designing and building your treehouse? Landscape timbers are a great material for constructing a treehouse. They’re strong, durable, yet lightweight enough to maneuver into elevated areas.

Also, they have a natural aesthetic that’ll give your treehouse a rustic charm. Designing your treehouse with landscape timbers is a fun and rewarding project the whole family can enjoy.

Making Outdoor Stairways

Selecting sturdy, rot-resistant wood is important when making outdoor stairways. Cedar and redwood are good choices, as is treated lumber (which is pressure-treated with chemicals to resist rot and insects).

Note that treated lumber is more expensive than untreated ones but they last longer. 

I really like the Manufacturer Direct 2 in. x 4 in. (1 1/2″ x 3 1/2″) Construction Redwood Board Stud Wood Lumber (link to Amazon). You can purchase it in a variety of colors including black, red, yellow, light or dark brown, and more.

Also, the wood is sourced from renewable forests, so you can be sure using this won’t harm the environment in any way. 

For the most durable stairway, use treated landscape timbers for the stringers (the supports that run perpendicular to the steps) and untreated lumber for the treads (the surface of the step).

With planning and basic carpentry skills, you can build a safe and attractive stairway using landscape timbers. 

Making a Patio Deck

A patio deck can be a great addition to any home, and landscape timbers are an ideal material for this kind of project.

Landscape timbers are sturdy and weather-resistant, making them perfect for outdoor use. They also come in various sizes and colors, so you can create a deck that perfectly suits your needs. 

In addition, landscape timbers are easy to work with and relatively inexpensive, making them a great option for DIY projects.


Landscape timbers are popular for many projects because of their natural beauty and durability. They’re also rated for ground contact applications, so you can feel confident using them in your next landscaping endeavor without worrying about them deteriorating in no time.