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I am planning to power wash my deck and stain it afterwards. But I am not quite sure the correct procedure for this process.

After power washing the deck, can I stain the deck immediately or should I wait some time?

Should I stain the deck first or apply the sealant first? Should there be any time gap between these two procedures?

Moreover, which kind of protective clothing should I wear when applying the stain and sealant?

  • after washing let it dry first. – ryanwinchester Apr 27 '13 at 8:20
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The first step is to clean the deck. A very simple and inexpensive method is to wet the deck, spray or scrub on a mixture of 1 cup TSP, 1/2 gal household bleach, and 2 gal water. Scrub it with a course, stiff broom. Then either rinse with a hose or power wash off before it dries completely on the surface. this works as good it not better than expensive deck cleaners. Note: When using a power washer, use a wide spray nozzle. Be careful not to be too aggressive with a power washer as it can damage the wood and leave divots.

Second, let the deck dry completely. This may take a day or two depending on weather conditions.

Third, apply deck stain. You can use any good oil or modified oil based deck stain. You can choose from transparent, semi transparent or solid. The most popular for older pressure treated decks is semi or solid. For cedar or redwoods, transparent or semi is favored. Usually one coat is enough, but on very porous or softer woods, two coats may be required for a good even finish.

Application hint: apply stain with a 3/8" nap roller on a pole. Do three or four boards wide, then over-brush the area with a fairly stiff bristle brush to work the stain into the grain of the wood. You could also use a 1 or 2 gal pump sprayer to get the stain on fast, then over-brush. A lot faster and easier than using a brush only.

You're done. There is no need to put a sealer over good grade stains. Never put a sealer on before you stain, as it will block the stain from penetrating and adhering to the wood.

Wait 24 hours before using your deck after staining. Don't stain if there is rain or temps under 50F predicted within 12 to 24 hours.

  • 1
    What is TSP (first ingredient in the cleaning mixture)? – Mike Eng Apr 18 '16 at 17:48
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    Probably trisodium phosphate. – hBy2Py Aug 26 '16 at 0:30
  • Oops: pinging @MikeEng. – hBy2Py Aug 26 '16 at 1:42
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I agree with Shirlock but I would not power wash within a week of staining. You would be surprised the amount of moisture that stays in your lumber after power washing.

When I wash something I want it perfectly clean and I do tend to overdo things so do not take my findings as average but I am sure they aren't way off.

I power washed my house before painting - wood siding. Before power washing it was at about 11% moisture content - dry season. The day after power washing it was at 23% in some areas - range was 14-23%. It was almost a week later in 80F degree weather highs and no rain before I got consistent moisture content before washing - used a friend's moisture meter...

Do you need to buy a moisture meter? No. Just power wash a week before and hit it with soap/water/sponge the day before.

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Pressure wash (use bleach/Jomax -- read the directions first) and rinse.

Allow to dry for one week.

Don't add moisture the day before!

Sweep off any debris and stain. (Usually wait 24-48 hrs after staining before light traffic).

SIDENOTES:

  • Wear vinyl/latex gloves that can be discarded.
  • Wear old clothes.
  • Work in shade or cooler times of day when possible.
  • Tarp and tape areas you don't want to get stain on before starting (the sidewalk, sliding doors, trim, siding, etc.)

Use oil-based semi-solid stain (it will last longer than semi-transparent stain. Cabot's is a good brand) on raw wood or on previously oil-based wood. Oil based only gets one coat.

Use water-based solid stain on any other previously coated deck. Remove all loose or peeling stain first. Strip if necessary. Always apply two coats oof water-based stain.

A water test can determine when it is time to re-stain. Sprinkle water on the surface to test whether wood is absorbing water, or if it beads up like a car wax. If stain is no longer protecting wood it is time to re-stain.

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(After power washing the deck, can I stain the deck immediately or should I wait some time?)

Do "NOT" use a bleach/bleach cleaner on your wood deck if washing with power washer do "NOT" use the pressure as a stripper (removing old paint or stains or moss) use it to rinse only. If it was me I would use a wood cleaner and just use the pressure of a garden hose. as for dry time I would give your deck if in direct sunlight 5-7 days dry time, if shaded give more toward 10 days.

(Should I stain the deck first or apply the sealant first? Should there be any time gap between these two procedures?)

The sealant will already be within the stain so "NO" sealant is needed. I like Oil to help maintain wood, helps to stop warping and splitting of the wood.

(Moreover, which kind of protective clothing should I wear when applying the stain and sealant?)

depends on sensitivity I would wear old clothing if using a oil or a water based solid/transparent stain, rubber gloves, eye protection.

most importantly dry time of the wood and no moisture or rain 24 after application of stain.

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sand your deck after cleaning.. it will open up the fibers and take take the stain much better and will last longer.. i use a 40 grit then hit with 60 or 80 grit after initial sand but you don't have too ... use a deck sander if you like but a 6" orbital is better.. its a little harder but would work best if you use an orbital ... get the dust off and then stain .. if you power wash without sanding after and just hit it with stain you will have problems next season .. likely have to do it all over again ... good luck ...

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