From About This Project
Before you revive a tired-looking deck, look it over to see that all the wood surfaces are sound. If the wood is rotten, a screwdriver will push easily into the wood and the surface fibers will pull away easily. No amount of cleaning is going to bring it back. If you have damaged wood, replace it with new.
Deck cleaners are formulated to clean a deck surface whether it has a stain or sealer on it or not. However, if you have an old finish that's worn out, the cleaner will do a blotchy job. It'll clean the worn spots differently from the spots that still have finish on them. Look for signs of an old finish line. A stain finish is easy to spot because it leaves signs of wear in high-traffic areas. A sealer is harder to spot, but you can tell if it's worn out because it'll no longer bead water. Old sealers usually will come off with a deck cleaner. Look for a film in areas with lower traffic. If you detect a film, use a stripper on the railing (like we did) to get rid of it before you apply a cleaner. Examine the railing in the same manner as the deck boards.
The deck stripper is designed to lift off the old finish (stain or sealer) and get the surface ready for the deck cleaner to do its work. Save time and stripper solution by first scraping away most of the old finish residue, using an ordinary paint scraper. It may sound daunting, but keep in mind that you don't need to get down to bare wood! Just scrape the surface enough to remove loose, flaky finish. Don't spend more than two hours doing this on an average-size (10 x 16-ft.) deck.
The deck we cleaned for this article had all sound wood, but the semitransparent oil finish on the railing was starting to flake off. So we stripped the railings before applying a cleaner. The deck boards, on the other hand, were unfinished, so we used a deck cleaner only. It had been several years since this deck had received any attention, but it cleaned up beautifully.
Deck Strippers and Cleaners
A deck stripper is used to remove old loose stain and deck sealers, before cleaning and brightening. It breaks the finish loose from the wood like a furniture stripper does. Several brand names are Wolman DeckStrip, Flood Powerlift and Superdeck Wood Stripper. These products also enable you to get rid of an old color and apply a new stain color. The deck stripper products are most effective on oil-based finishes. New products that remove latex stains and finishes will be on the market soon.
There are basically two types of deck cleaners: One type (liquid oxalic acid or powdered hydrogen peroxide) removes a thin layer of gray, dead wood fibers from the surface and exposes the fresh wood beneath. Several brand names are Wolman Deck and Siding Brightener and Rejuvenator, Flood Dekswood and Superdeck Wood Cleaner. The other type has a bleach base that removes unsightly black and green stains on the surface such as mildew. If you notice this condition, clean off the mildew first and rinse, then use one of the standard deck cleaners mentioned above.
For the best buy, pay attention to the concentration of cleaner in the 1-gallon plastic jug. Some of the cleaners appear to cost more, but on closer inspection, you'll see that the gallon container mixes with water to make 5 gallons of cleaning solution (enough for a large deck).
The Right Tools and Safety Gear
Even though this project is low-tech, there are a few things you probably need to buy. Get rubber boots and rubber gloves. I like the gloves that cover up the forearms to protect against stripper that splatters and drips. Buy a paint applicator. I've tried brushes and rollers and this tool beats them all. You'll also need a 1- or 2-gallon pump sprayer (buy one specifically for deck cleaners) and a hand-held stiff-bristle nylon scrub brush to scrub the stripper after you apply it. For scrubbing the deck surface, you can use a stiff brush (and I mean stiff!) with a pole handle. Also wear safety glasses and old clothes because the stiff bristles of the scrubbing brushes can spit tiny droplets everywhere.
You'll also want to protect any plants surrounding your deck. Be sure to remove the plastic soon after cleaning and rinsing so it won't stress the plants.
Skip This Job on a Hot, Sunny Day
Both strippers and cleaners evaporate rapidly and become ineffective on hot, dry days. A cool, overcast day extends the working time of these solutions. Besides, you'll want to make this messy job as comfortable as you can. This is hard work, so expect to sweat. You can work on the deck in sections (stripping railing sections) over several days if you don't have an eight-hour block of time to do the whole deck.
Keep Strippers and Cleaners Working
Insects and spiders are about the only things I've seen that'll stay put on a vertical surface. In contrast, strippers run down vertical surfaces easily. The only way to keep the stripper in contact with the wood is to constantly go back with your applicator and smear the stuff to the top.
You only need to keep the stripper in contact with the wood for 15 minutes, then scrub and rinse.
Mixing Your Cleaner
Many deck cleaners are concentrated and require additional water. Stir the mixture with a clean piece of wood and put the top back on. Pump the sprayer until you feel resistance (usually about 25 pumps or so). Then grab the wand and spray the solution on the deck surface. Wait about 15 minutes before you start to scrub. After scrubbing, flush the surface with your garden hose sprayer until the deck looks clean. It's best to work small sections at a time; otherwise, the solution will dry before you get a chance to scrub the surface with a stiff brush.
Apply a Good-Quality Finish
Let your deck dry for a couple of days before applying a sealer or stain. For our deck railing, we applied a semitransparent oil stain mixed to match the siding of the house. We brushed it on and carefully cut in around the deck boards. We didn't want a colored stain on the deck boards, so we applied CWF, a clear finish/ sealer made by Flood Co. This finish looked great and gave the decking a warm, fresh look. Avoid using stain on the deck boards because they quickly show wear.
Keep an eye on your deck and be prepared to clean and reseal it every couple of years. The longer you wait, the more weather-related damage can occur.
Buyer's Guide
Cleaners, strippers, stains and sealers are available at most home centers and lumberyards. For product information and where to find deck cleaners and strippers, try these manufacturers:
Cabot Stains: 800-877-8246. www.cabotstain.com
Duckback Products: 800-825-5382. www.superdeck.com
The Flood Co.: 800-321-3444. www.floodco.com
GE Silicones WeatherMate: 800-275-4372. www.gesealants.com
Olympic: 800-441-9695. www.olympic.com
Thompson's Deck Wash: 800-367-6297. www.thompsonswaterseal.com/products/cleaners.asp
Wolman Wood Care Products: 800-556-7737. www.wolman.com