How long does pressure treated wood last in ground?

Asked By: Marylee Aschhoff | Last Updated: 29th June, 2020
Category: hobbies and interests woodworking
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The Forest Products Laboratory and other research groups have shown that treated wood stakes placed in the ground for more than 40 years remain rot-free. But young pressure-treated decks, many less than 10 years old, are being shoveled into landfills.

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Also asked, how long does pressure treated wood last?

40 years

Additionally, how long will treated plywood last in the ground? For a comparison, in the Southeast US, with it's high rain & humidity, in-ground swimming pools with vinyl liners are built with PT plywood walls completely buried in the ground. They are guaranteed for 40 years.

Considering this, can pressure treated wood touch the ground?

To start, pressure-treated wood is softwood lumber, typically southern yellow pine, that's been chemically treated to resist rot, decay and termites. Lumber that's stamped "Above Ground Use" should be used only where it won't touch the ground, such as deck railings or fence boards.

How do you make pressure treated lumber last longer?

Extending the life of your treated wood

  1. Applying a sealant to the wood is the best choice no matter how the wood is used.
  2. Filling all nail and screw holes is another way to extend the life of the wood.
  3. Applying concentrated treatment chemical to any cut ends will increase the life of the wood.

36 Related Question Answers Found

Which is better cedar or pressure treated wood?

As a general rule, cedar will remain in good condition and require less maintenance than pine if installed above the ground. Pressure-treated pine is less likely to decay if planted in soil, so the posts often last longer.

How do you keep treated lumber from warping?

How to Prevent the Warping of CCA Treated Wood
  1. Work with the wood before it dries. If you use the wood while it is still damp (and therefore straight) you can secure it into place before it dries, and it can dry in place in a straight manner.
  2. Clamp the wood.
  3. Use screws, not nails.

Do you need to seal pressure treated wood?

However, most pressure-treated wood should have periodic sealing against moisture, preferably every year or so. However, most of the water-repellent sealers sold at home centers, paint stores and lumber yards are suitable for pressure-treated wood as well as other outdoor woods such as cedar and redwood.

Do termites eat pressure treated wood?

Pressure-treated wood is resistant to termites, but make sure that there's no contact with soil. Pressure-treated wood is wood that has had a chemical preservative forced into the pores to form a barrier that resists decay and wood-eating insects like termites and carpenter ants.

What are the different grades of pressure treated lumber?


There are many types of treated lumber.
There are three main families of treated lumber used in construction: Borate, Alkaline Copper Quat (ACQ) and other rot-resistant treatments, and non-combustible (Non-Com). See the complete list under Additional Information.

How do you protect wooden posts in the ground?

Double wrap the bottom of the post with Grace ice and water barrier. This stuff sticks to wood like super glue. Finish the wrap a couple inches above ground level. Do no seal the bottom of the post, the long grain end.

What is #1 pressure treated lumber?

#1 lumber grade is to be used when both strength and appearance are important. This product is #1 lumber grade meaning the boards contain small and few knots within the board. The strength of #1 grade lumber is the best you can get on the market.

How long will non pressure treated wood last outside?

Some say that untreated 2×4's can last up to two years before showing signs of rot and others say it can last even longer. When deciding if you should you use an untreated 2×4 it depends greatly on the application, how much weather and sun it's exposed to and if it's making ground contact.

Will pressure treated wood rot if buried?

Pressure-Treated Wood Makes the Grade
Pressure-treated wood in contact with the ground needs the most protection, and will rot in just a few years if you use the wrong grade. If your wood will touch the ground or be buried, you should get the highest grade you can, up to .

How do you keep pressure treated wood from rotting?


Pressure treated wood can crack and split from water exposure and this will allow fungi to get into the cracks and create wood rot. If you have a pressure treated deck this can be a harder problem to avoid. The best way to protect your treated wood deck is to apply a deck preservative.

Can pressure treated posts be set in concrete?

Simply setting the posts in concrete does create a condition that will accelerate rot in the bottom of the posts. With pressure-treated posts, the rot will be slow. Concrete should be poured around the post - no concrete under the post.

Can you pressure treat your own lumber?

Untreated wood like pine will only last a year or two if it is touching moist ground. Pressure-treated lumber is wood that has been immersed in a liquid preservative and placed in a pressure chamber. The most common chemical used to treat lumber used to be chromated copper arsenate, or CCA.

Can I build a deck directly on the ground?


Building an 8-by-10-Foot Floating Deck
Floating decks can be set directly on the ground or, preferably, a bed of gravel. But it's best to support the deck on concrete blocks. This keeps the wood off the ground and away from moisture so the wood stays drier and lasts longer.

When should I use treated lumber?

While many homeowners wonder if they should use pressure-treated wood for a specific project, the answer is simple. Wood for any outdoor project should be pressure-treated; wood for indoor projects should be left as is. The sawdust from pressure-treated wood is an irritant to the eyes, skin, and nose.

Should deck boards have a gap?

The goal is to have about an 1/8-inch gap (the diameter of an 8d nail) between boards after the decking has dried to its equilibrium moisture content. If the decking is installed wet, as is often the case for pressure treated material, it is best to install the boards tight, letting gaps form as the wood dries.