It's challenging to keep sealing your deck so it looks great forever but that's what protects the wood (decks, porches, fencing) from the elements. To avoid this chore, many homeowners are now building decks from the new composites which might get dirty but don't show the wear and tear like a poorly maintained wood deck, and the added benefit is composites don't rot.
When you're ready to seal your deck, the challenge is deciding if you want to use a clear seal or a deck stain. This decision isn't the same as painting a room where you can easily change colors. Stains penetrate the wood, and while they wear away over time, you need to keep using the same tint for a uniform look.
Choices for Sealing Your Deck
Deck finishes are made to “seal out the elements”. Whatever type of deck finish you pick, it should accomplish 3 things (should all listed on the label) – repel water, preserve the wood with a mildewcide and screen out the sun's ultraviolet rays. There are only 2 types of deck finishes you should consider:
- Clear sealers – have no pigmentation.
- Stains with varying degrees of pigmentation – from a little pigmentation or “tint”, semi-transparent or solid. Stains penetrate the wood which lets them stand up to foot traffic.
- While it's common to paint a house (siding and trim), you never want to paint a deck as the paint forms a surface film which doesn't hold up to foot traffic.
If you find yourself with a painted deck, the best solution we've found is to pressure wash or strip off as much paint as possible and match the color with a solid stain that blends well. You should be prepared to touch up the deck with stain as more of the remaining paint peels which can take years.
Clear Versus Stains with Color?
Stains provide color options and the pigmentation helps protect the wood from the sun's ultraviolet rays. The more opaque (solid) the stain, the more protection you get for your wood deck.
Transparent or “clear” deck stains are popular because you can see the wood's natural grain. They're easier to apply because they're transparent so you can't see any brush marks like you will with stains that have pigmentation. The negative is that clear finishes, without pigmentation, aren't as good at blocking the ultraviolet rays and clear stains break down faster so you'll have to reapply the stain once a year.
Semi-transparent stains add color to a deck while letting the wood's natural grain show through. With the pigmentation, you get a more effective barrier against the sun's ultraviolet rays, and often you can wait 2 years before you need to apply a new coat of stain to your deck.
Semi-solid stains are offered by several manufacturers like Cabot Stains. They have enough pigmentation to last 2 to 3 years under normal conditions. With a single coat you can still see some of the wood's grain while a second coat will provide an opaque finish that is similar to a solid color stain.
Solid color deck stains contain more pigmentation and like interior paints, the choice of flat or satin finishes. There are lots of color choices and home owners often choose a solid stain with an older deck because it hides the uneven discoloration that comes with aging wood. The drawback is that solid stains don't hold up as well to foot traffic. If you really want a solid color, make sure you find a product that is meant for deck surfaces.
Other Decisions Regarding Deck Stains
Water or Oil Based Stain? Water based stains are easier to clean up and release fewer VOCs into the air. While more environmentally friendly, they need to be re-applied more frequently (every 1 to 2 years) and they're more likely to crack and peel. For homeowners that are sensitive to chemicals, this is a good choice. Oil based stains penetrate deeper into the wood making them less likely to crack or peel, and they last longer (2 to 4 years). Oil based stains are smelly (means they release VOCs) and need to be cleaned with solvents so you need to use a natural bristle brush.
Do-It-Yourself or Hire a Professional? If you're good at focusing on details and comfortable with preparing your deck (read Tips to Clean and Seal Decks) and you plan to use a clear finish, then doing the job yourself should work just fine with the right tools and product. If you're going with a pigmented finish that shows your brush marks, you should give serious thought to hiring a professional. If budget is a concern, consider doing the prep yourself and find a handyman or painting contractor who will work with you under this arrangement.
Cost of the Stain? Don't fall into the trap that you're saving money with a cheaper product. You need to include both the cost of the stain and the value (or cost of hiring a professional) of the time it takes to apply the stain. My recommendation is you always buy your paints and stain at a paint store that stands behind their product, although admittedly product quality changes over time so the best way to learn which manufacturers offer the best stains is to ask a painter.