Why Should I Stain my Deck?
Let’s face it, no one enjoys spending time to stain a deck, but if your deck is advanced in years it usually requires some protection from the elements. The elements are not friends to your deck – the sun literally burns the surface of the wood and rain and snow inject the wood with moisture. Your deck gets more surface cracks or checks and the wood fibers pull apart from the constant expansion and contraction due to the changing moisture content. What can we do to limit the damage done by the elements? That’s where it’s important to learn how to stain a deck. Deck staining seals the wood to keep the moisture out, while still allowing it to breathe. It also serves as a UV inhibitor and reflects sun rays away from the wood.
Types of Deck Stains
There are numerous products available when looking at how to stain a deck, but you can group them all into three main types of sealers. (1) Transparent sealers come in varying amounts of color and allow all the woodgrain to show, but contains minimal amount of sun protection. (2) Semi transparent sealers are more solid than transparent sealers, which makes the grain harder to see, but also protects better from the sun. (3) Semi-solids are the heaviest and paint-like. They hide all the grain and some of the wood’s texture. A good rule of thumb when choosing stains is this: the more color (or the more solid the stain), the better it protects from the sun, but less grain and texture is allowed to show through.
Sometimes people choose wood decks for the beauty and the woodgrain. Other times, wood is used because it costs less than the alternatives. To maintain the natural beauty of the wood, I prefer to use transparent sealer with some color, and occasionally a semi-transparent for decks that require more protection. I don’t like to use semi-solids for decking. If moisture gets under the surface of the stain (and it will), semi-solids can peel. Semi-solids will usually last longer than transparent sealers, but when the sealer starts to fail, the semi-solid will peel while the transparent will just fade away. Finally, remember that most stains go on dark, but will lighten up as they age.
How to Stain a Deck – Step by Step Guide
The first step in how to stain a deck is to remove all the junk from between the boards. This build-up can include dirt, pet hair, leaves, etc. I built a crude scraping and cutting tool to accomplish this task. I simply screwed and taped a reciprocating saw blade to a narrow scrap of wood. If you wanted, you can actually use a reciprocal saw, but that requires getting on your hands and knees. There is also the potential to cut through a floor joist, so an actual saw is not recommended. With our homemade tool we can easily cut through the crud. Some of it will fall below the deck and other pieces will end on top of the deck. The stuff that’s on top can easily be blown or washed away.
Preparing to Stain a Deck
If there is an existing stain and it’s compatible with your new deck stain, you might be able to simply clean the deck and apply the new stain. Most manufacturers don’t recommend using their stain on other manufacturers’ stains, but if the finish is almost gone, I wouldn’t worry about applying the new stain. However, if you cover an existing stain with a transparent sealer, then the old stain will still show through. You can help this problem by using the same colored stain as the existing deck stain.
When instructing people how to stain a deck, I always recommend that the existing stain be removed if the colors of the two stains differ, or if they aren’t compatible according to the manufacturer’s recommendations. If you’re lucky, you can simply use a good deck cleaner and solid scrubbing. If that doesn’t work, you need to strip the wood with a chemical stripper or sand down the old sealer. Chemical strippers are fairly harsh (they will burn your skin) and results can be unpredictable depending on the condition of the existing stain. Sometimes it takes multiple attempts to completely remove the old stain, and this is especially true for vertical surfaces. On the other hand, sanding is a lot of work, but the results are predictable and you can be sure it will remove the stain. Sanding large, open deck surfaces can be pretty painless with the right tools. Also, when you sand you create a smooth, new surface. Sometimes I use a combination of a good deck cleaner, chemical strippers and sanding when preparing to stain a deck.
If you decide to use chemical cleaners to prepare your deck to stain, there are lots of products to choose from. They come in either one- or two-step processes. For the two-step process, the first part cleans the wood and the second bleaches the wood and removes tannins that can stain the surface. One-step process cleans and bleaches in one application. For older decks you can use a one-step process because tannin stains are not much of a problem. However, omitting the bleaching step in a two-step process could leave your deck much darker.
The chemical cleaner is applied to a dry deck surface with a pump sprayer or is rolled with a paint roller. Be sure to wear latex gloves to prevent burning skin and old clothing that can afford to get bleach spots. Some cleaner manufacturers will want you to apply their products on a wet surface. It’s best to apply these products on cooler or overcast days. Once you apply the product, you want to keep the surface damp until you are ready to rinse it off. Make sure you pay attention to the label for both accurate directions and safety. You want to keep most chemical cleaners away from metals, like door thresholds. Although most claim to be environmentally safe, it’s still a good idea to wet down nearby vegetation. As you apply the chemical cleaner, you will want to scrub the deck with a heavy-bristle deck cleaning brush. This will help in the removal of old stains, dirt and anything else that may be stuck to the surface. Your knees will thank you if you use a brush with a long handle. After the old deck stain and dirt are removed, you will rinse the surface off. A pressure washer can get the job done quickly, but you must be careful not to get too close to soft woods or it will literally tear the deck up. If you don’t want to take the risk, a garden hose with a good stream works as well. Then, let the deck dry for at least a day or longer.
If you decide to sand your deck to prepare for the stain, the first step is to sink all screws or nails below the deck surface. This is done to protect the tops of the fasteners as well as the sandpaper. If the deck was screwed down, you need to back out the screws and then drive them a little deeper. Depending on the quality of the old screws, some inevitably break or strip and need to be replaced. For the bulk of the deck I recommend a large oscillating floor sander. You can usually rent these at your neighborhood tool rental. A floor drum sander also could be used and it may be quicker, but you run the risk of sanding too deep. If the deck is very rough, I recommend starting with a coarse-grit sandpaper (36 or 50) and make multiple passes as needed. Gradually step up the grit until you finish with 100 grit. 100 is suitable for a deck, but you probably need a higher grit for an interior floor. The purpose of using a finer grit is to remove the sanding marks made by earlier sanding. For spaces where the floor sander can’t reach, such as the edges of the deck and against the house, we use a random orbit sander and again gradually move the grit from coarse to fine. It’s helpful if your sanders can collect dust so you can save time on clean-up and the sanders will work more efficiently. You need to clean the deck after sanding to remove all the dust and open up the pores in the wood that get clogged when sanding.
Staining the Deck
Now comes the actual staining when learning how to stain a deck. It’s important that you read the directions for your specific product to learn about recommendations for applying, but most stains can be applied with a pump sprayer, a roller or a simple brush. I prefer to roll it on and then back brush it. This ensures the sealer gets into all the cracks and crevices and is evenly distributed. Try to stain one or two boards at a time and for the full length. If you stain half of a board and come back later to stain the remainder, you could end up with visible lap marks. Not good.
Wipe Down the Stain
For those who are just learning how to stain a deck, this final step is the one that many people leave out and with disastrous results. You need to make sure you wipe down the deck with a cloth rag within 15-30 minutes to remove any excess sealer. If you don’t do this, you can end up with a sticky deck and no one likes that. Allow the stain to dry a day or two before you moving furniture back and using the deck again.
WARNING: When finished wiping down the deck, you need to dispose of your oily rags. You should place them in a metal container, soak with water and seal the can. One of my guys learned the hard way about spontaneous combustion – it’s not a myth. He left the rags in his truck on a very foggy evening. At about 2 a.m. a neighbor called to say he could see flames in his truck. By the time the fire department arrived, the truck was completely ablaze and not salvageable.
Now that you’ve learned how to stain a deck, you can add this to your professional skill-set or make your old deck look like new. Let me know if you have any questions about how to stain a deck and I’ll do my best to answer them.