Pressure Treated Lumber - Staining Pressure Treated Wood

Wood is no doubt one of the most versatile materials for construction purposes. Nevertheless, wood obtained from almost all varieties of trees are susceptible to termites, insects, bacteria, fungi, and other microbes. When wood comes in contact with atmospheric moisture or the ground for a certain period, it gets easily attacked by microbes and pests, thus reducing its durability. This is where the question of pressure treatment comes to the picture. Pressure treated lumber refers to the wood that has been exposed to chemical preservatives under increasing pressure, so as to make it insect resistant.

About Pressure Treated Lumber

While soft, untreated wood lasts for only 1 - 2 years after exposure to moist soil, the durability of a high quality, pressure treated wood is 20 years or more. In the process of pressure treatment, wood is introduced into a holding tank under very low pressure, thus creating a vacuum-like condition. Then the tank is filled with specific chemical preservatives. The pressure inside the tank is subsequently increased, so that the preservative is forced deep inside the wood. Then, the treated wood is removed and cured further for commercial usage.

Pressure treated wood is used for building decks, posts, tables, and other wooden furniture, gardening components, and at times, building foundations. Nevertheless, using it in garden soil can cause the preservatives to leach out into the soil, thereby causing certain adverse effects on plants growing in the surrounding area. Considering the problems associated with this type of wood, one should always check the chemicals used at the time of treatment before purchasing it. The lumber yard may also suggest different versions of pressure treated wood, depending on whether you are using it for ground contact projects or above ground projects.

How to Stain Pressure Treated Lumber

Irrespective of whether it is an old post or a newly purchased pressure treated wood, proper staining is a good approach to restore its color, appearance, and strength. But painting treated lumber should be avoided as the paint holding capacity of such wood is very low. It is to be noted that the chemical preservatives used in the making of pressure treated wood may be harmful to humans and animals. Hence, it is advisable to use protective gears while staining the pressure treated woods.

Prior to application of the stains, clean the surface of the pressure treated lumber by using an appropriate cleaning solution. In case, you are staining an old wood, pressure washing (within the range 1200-1500 PSI) is a preliminary step, which is not needed for the new one. To deal with mold or mildew problems, you can apply diluted bleach solution for killing them. While doing so, make sure you use mouth covers to avoid inhalation of the fumes.

After cleaning, allow the lumber to dry completely. Coming to the staining part, decide the suitable stain product and color for the lumber. Avoid using water-based products for staining treated woods, if they are meant for use in sunny areas. Regarding color, you can opt for light color stains or semi-transparent stains with ultraviolet light protection to impart a natural shade. If the old wood has cracks, a solid color stain is the best choice.

Some stains can be applied even on wet surfaces. In such cases, you can directly proceed with the staining steps (without drying) by following the guidelines, provided by the product manufacturer. Using a regular paint brush, roller, or paint pad, you can start applying the stain evenly. If available, make use of a sprayer for uniform stain application. However, this approach may require a higher amount of stain than the regular brush staining method.

For solid color stain, a single thick layer stain is sufficient for preservation of the pressure treated wood. In the following year, you can apply one more coat to increase durability. For the clear coating stains, it is better to put two coats. Also, clear finish requires frequent application, at least once in six months. Lastly, don't forget to seal the open grains to prevent water penetration. Overall, staining pressure treated lumber once in a year will surely increase its aesthetic value and durability.