Expert Advice: It's Tool Time on Deck

"A determined soul will do more with a rusty monkey wrench than a loafer will accomplish with all the tools in a machine shop."

– Robert Hughes

Thinking about tackling that deck cleaning and treating job? Make it easier by using the right tools for the job. From safety gear to applicators, having the necessary tools on hand will make the job a snap.

Safety First

Protect your body from any splashes which may occur while working with cleaners and waterproofers. A long sleeved shirt, long pants and closed toe shoes work for clothing – I just use my old "painting" duds that I don't mind getting dirty. Then add rubber gloves, safety goggles, maybe an old hat, and you'll be in business. Anything nearby you want to protect, like plants or other surfaces, should be sprayed with water and covered with plastic sheets. As soon as you're done with the job you'll want to pull the plastic off and spray the plants down again to dilute and neutralize any of the cleaner they might have come in contact with.

Cleaning the Deck

First, you'll need to clean the surface being sealed. Make sure that all of the dirt, grease, old coatings, stains from mildew, mold, fungus and algae are removed to help ensure that the new finish penetrates, so it will look great and hold up over time. There are five different Thompson's^® WaterSeal^® cleaners, each suited to specific situations. Use Thompson's^® WaterSeal^® Deck Wash on dirty decks with no residual finish. For more muscle, Thompson's^® WaterSeal^® Heavy Duty Deck Cleaner not only removes dirt (stains from mildew and mold), but also it can take off most types of weathered finishes, including semi-transparent stains. If your wood is treated with a solid stain or a difficult-to-remove waterproofer, Thompson's^® WaterSeal^® Maximum Strength Deck Stripper will get the job done. If you're working with cedar, redwood or mahogany, you'll want to use Thompson's^® WaterSeal^® Deck Cleaner & Brightener to restore the wood's color. And our latest cleaner, Thompson's^® WaterSeal^® Oxy Foaming Action Exterior Multi-Surface Cleaner, can be used to remove stains from dirt, mildew, algae & fungus (using a non-bleach, chlorine-free oxygenated foaming formula) on many outdoor surfaces.

Tools for cleaning need not be expensive or complicated. A plastic garden sprayer works for most types of cleaners, except strippers, which should not be sprayed on. Don't use a metal sprayer or container – most cleaners are corrosive to one degree or another, and will react with the metal! After waiting the recommended time, use a synthetic, stiff bristled brush to scrub the surface. Then use a garden hose or pressure washer to rinse away the residue.

A pressure washer may not be a necessity. Most decks can be cleaned with the simple tools I listed above, but a pressure washer might come in handy if you have a very large deck or other uses for it around the house. You can choose a gas-powered model, which requires a bit of maintenance to keep running year after year, or one of the newer electric types. The electric pressure washer might be the most convenient and cost effective type for the casual user, where the gas type might work better for someone who uses a pressure washer regularly.

Either way, take care in how you use it – using the lowest pressure necessary for cleaning will assure that you don't damage the wood with the force of the water. That pressure can be as low as 1200 PSI if you're working with a soft wood like cedar, but in most instances, 1500-2500 PSI will be sufficient to complete the job quickly and efficiently. Also, using the correct tip size when pressure washing is important: a "zero" tip is too strong for use on wood, a 15° can be carefully used to remove paint or stain, a 25° can be safely used for general cleaning, and a 40° tip should be used for rinsing and on lightly soiled surfaces. Minimizing damage, like "feathering," on the wood surface, is the key here.

Once your cleaning job is done, you've completed the toughest part! Follow the directions on the waterproofer label to decide how long to let the surface dry before applying your protective coating. That can be as long as a few days for many products, or as short as a few hours for products like Thompson's^® WaterSeal^® Advanced line of waterproofers.

Waterproofing the Deck

Pick a nice day with a good forecast (most waterproofers require a day or two of nice weather to completely dry – again, check the label on the product you're using), and try not to work in full sun. You'll find it easier to keep a wet "leading edge" as you work, and you'll be able to get a nice even finish.

If you're protecting your deck with one of the clear or tinted Thompson's^® WaterSeal^® Wood Protectors (either the traditional oil-based formula or the newer, water-based Advanced line), then the pump-up garden sprayer that you used with your deck cleaner could handle the application job. After spraying on the waterproofer, come back and "back-brush" with a paint pad or brush to even out the finish and ensure the best absorption of the coating.

You cannot use this type of pump-up sprayer to apply exterior stains, including Thompson's^® WaterSeal^® Deck & House Waterproofing Stains. Exterior stains have more pigment content than clear or tinted waterproofers, and this pigment may clog the nozzle. If you think spraying is the way to go, use a compression driven sprayer set for low-pressure, then come back and brush in the stain to ensure even coverage.

Of course, brushes and rollers have served folks well for decades on these types of projects. If you choose an oil-based-finish, you'll want to use natural bristled brushes or roller covers. For water-based finishes, use synthetic brushes or rollers. Again, reading the label will tell you the recommended type of applicator for your particular finish. For example, some water-based finishes recommend against using a roller, so a paint pad is the best alternative.

That's what I used to apply Thompson's^® WaterSeal^® Advanced Natural Wood Protector to my deck, working about four boards at a time. Also, I found that a seven-inch pad fit nicely into an empty plastic baby-wipe container, where I kept extra product to keep the paint pad wet as I worked.

Cleaning up typically requires mineral spirits if you use an oil-based waterproofer or stain, while soap and water are all that is required for water-based waterproofers and Latex Waterproofing Stains – but double check the label to be certain. Cleaning up well, drying, and carefully storing your tools ensures they're ready for use the next time you need to start a project.

Come to think of it, there might be one or two more tools that you need at this stage of your project. A comfortable deck chair so you can sit and admire your newly finished project, plus a glass of lemonade to toast a job well done!

— Jeff Wilson