Protecting the exterior wood from the elements requires some effort due to the vulnerability of wood and several factors. Even if your exterior wood is a hardwood and pressure-treated, the proper maintenance and care will make it stay in top functional shape for many years.
Two major ways of preserving exterior wood are staining and sealing. However, to protect exterior wood efficiently, there are also different types of paints and waterproofing methods for maintaining different types of wood.
Types of Coating for Wood
1. The Exterior-grade Penetrating Stain
This is the most popular type of exterior wood coating. It contains water-repellent preservers which always contain a mildewcide to protect against the growth of mildew and UV light absorbers, which guard against exposure to the sun. It is available in water-based and oil-based formulations. It contains resins in the formulations, which enter the pores of the wood to add pigment and resist the harmful effects of the weather but permit the texture and woodgrain to show.
2. Film-forming Sealant
This sealant bonds to the wood’s surface like shellac or paint. This product type offers a highly glossy furniture finish and allows the natural woodgrain to show through. It is available in water-based and oil-based finishes. This type of coating leaves the wood with a lasting attractive, satin surface.
Note: that the exterior wood coatings are made with either oil or water. The oil-based finishes usually have small bits of resin and pigment that fuse together and form one big substance like a sheet. The water-based sealants or stain have resin and pigment that attach to one another as the finish dries.
Condition of Exterior Wood to be Preserved
1. New Wood
In an attempt to preserve your exterior wood, allow the freshly pressure-treated wood to dry prior to sealing or staining it because the wood is likely to still be "wet" from waterborne preservatives applied to the lumber. Therefore, leave the wood to dry for four to six weeks before using coatings on it.
2. Wood with Old Stain
First, remove the old stain before applying new stain if you are changing the colors or products. The old stain has a way of showing through the newly applied stain leaving blotchy spots in the finish. But if you are not changing color or product, you can clean the surface thoroughly before adding fresh coats.
3. Weathered Wood
Exposure of wood to sunlight causes the wood fibers to be damaged by the ultraviolet rays after some time. To get a fresh appearance, pressure-wash or sand the surface. While sanding is difficult and takes a longer time, pressure-washing is faster but make the wood surface to splinter or fuzz.
Preserving exterior wood could be complicated, but you can avoid the trouble by hiring a professional painting company and make your exterior wood last longer.
John Blane is a Commercial Facility Maintenance Director; well versed with maintenance design. His professionalism is apparent in all his endeavors!