Wood that’s in contact with the ground can rot. You don’t want your deck or fence to fall apart, so be sure to treat the wood to prevent rot from taking over. Here’s how to treat wood for ground contact so you don’t have to worry about mold and mildew moving in and taking over!
How do you protect wood that touches the ground?
You may have a problem with what is called ground contact. This refers to wood that rests directly on soil or other surfaces that are wet such as decking over a concrete patio, or porch railings and decks above grade. What happens is that moisture seeps into these pieces of wood causing them to expand and contract more than normal outdoor timbers.
This makes them susceptible to splitting, warping, and ultimately rotting if they are not treated properly. What do you need to do? There are many different kinds of chemicals used in preserving wood but one way to protect it from ground contact is by using what’s known as a ground contact preservative. What does a ground contact preservative do?
It actually soaks into all of the pores in your timber keeping it rot-free.
The best treatment product for ground contact wood
If you want to keep your ground contact deck in good shape, it’s important that you make sure that all of its pieces are treated with a high-quality sealant or preservative. But, there are so many options on how to treat wood for ground contact.
What product is best? Will an oil or water-based solution work best? As stated above Rust-Oleum Copper Green is most effective at preserving wood. This type of product will penetrate deep into each board and protect it from moisture and insects.
The only downside is that treatment doesn’t seem to sink deep enough.
Another good option available on amazon is Storm Protector Penetrating Sealer. This water-based product will also protect your wood from moisture and insects but you may need to apply a topcoat for extra protection. The upside is that it’s easy to apply and dries quickly.
If you want a product that you can use once and never have to worry about again, then I would recommend using Rust-Oleum Copper Green.
Tips on applying treatment to ground contact wood
There are three main types of treatment you can use on ground contact wood: silicate preservatives, phenol-formaldehyde (PF) preservatives, and copper-based preservatives. However most of these you can only get these from lumber that’s already treated.
How do you make wood last longer in the ground?
To make wood last longer there are no shortcuts the wood has to be protected with a good sealer or some other sort of treatment.
Traditionally people used diesel oil to treat ground contact lumber. The oil would be applied up to about a foot above the ground. This method seems to work well in prolonging ground contact lumber.
Touching the end grain is also recommended and can be done as shown in this video.
The industrial option is usually pressure-treating ground contact lumber.
Pressure-treated timber has been treated with preservatives. The preservatives are pushed deep into the wood grain using pressure.
The treated lumber will have no problem with rot if used as ground contact lumber. There are a few downsides to using this type of lumber though.
For instance, pressure-treated lumber is usually sold with high moisture content. This means you will soon run into split warp, check and twist challenges with this lumber as it dries.
Pressure-treated will usually have a green tint that may be ugly if a natural look is what is intended.
Wood Decisions: Redwood vs Cedar for Decking and Fencing