Pressure Washing A Deck
Wood restoration can be one of the most misunderstood services and one of the toughest for do-it-yourself homeowners. One thing to keep in mind is that the main reason a new deck sealer will fail prematurely is because the wood was not cleaned properly beforehand.
When wood becomes weathered, it needs to be cleaned prior to sealing. Cleaning a wooden deck can be a difficult task for a homeowner that is uneducated about the process.
Using a pressure washer can be an effective method. You must also use the proper cleaners to get the dirt and grime out that is deep down in the wood. Most people make the mistake of using too much water pressure when using a pressure washer. Wood is actually pretty soft and can damage easily from excessive water pressure.
Turning the pressure down on the washing unit or switching to a spray nozzle that has a bigger orifice will both successfully provide a lower suitable pressure. Using lower pressure will still give you a deep clean as long as you use a quality wood cleaner. Wood cleaners will break up the dirt and debris allowing a lower amount of pressure to be adequate in cleaning the wood without risking damage.
Some wood cleaners are caustic and raise the pH of the wood. Once the wood is clean, it is best to use a brightening or neutralizing product to lower the pH of the wood. Most any quality wood sealer will be more effective and last longer when it’s applied to a more acidic surface. It is highly recommended not to skip the brightening process after washing.
After the wood has been cleaned correctly and rinsed thoroughly, it needs to dry for a few days. You can check the wood with a moisture meter but it isn’t necessary. You don’t want to apply a wood sealer to the deck until the moisture level is below 10%. If you don’t have a moisture meter, waiting a few days is usually adequate time before sealing.
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22 Comments on "Deck Cleaning Tips"
Location is Chicago
We have a 20 year old deck. We power washed it 2 years ago and applied sealer. 2 years later, it looks gray and old again and some mold on the wood that doesn't get direct sun near the house. Here is my question…We are thinking of sanding the deck. If we do this, in what order should we prep the deck:
step 1 : sand
Step 2: deck cleaners and brightener
step 3: let dry for 48 hours and seal it within 14 days of cleaning it.
Is this the proper order? Also, if it rains day or two before the 14 days mark, will this ruin the wood or will we have to start all over? thanks.
-Deck cleaner and pressure wash.
-Lightly sand to remove any splinters
-Apply a wood brightener and rinse deck well
Rain does not harm a prepped deck. Just make sure wood is dry and free of any debris before staining.
Nice post.
I have just finished using Restoradeck kit twice on my 5 month old large cedar deck. I bought the kit and AC stain from you. My deck now has areas of white possible chemical stains especially around knots.. I followed the instructions to the letter used lots of water to rinse. Deck looks great when wet but really light when dry. I sure don't want to sand and redo at this point because I'm running out of time to stain. What do you suggest?
Best regards
Sounds like you had a lot of exposed wood cells that had oxidized from the UV. This can happen when cleaning and is not related to the Rad product as the wood cells have to come off prior to sanding. See this for more info on this and how to fix: https://www.deckstainhelp.com/wood-fuzzies-furring…
I have a trex deck with a wood-framed cable railing. The railing frame has begun to turn gray and acquire algae. I don't mind the gray, but I assume I need to clean and brighten the frame, then stain it in order to protect it from the weather. Because the wire railing is fragile, I don't want to use a pressure washer on the frame. Would you recommend using a simple brush to apply a product like Restore-A-Deck, and a hose to wash it off, or is a pressure washer necessary? Also, are you aware of any damage to trex if the product comes into contact with it?
Thank you in advance!
The cleaners should not harm the trex but you will need to spray on with a pump sprayer then light pressure wash or heavy scrub/rinse after the cleaner is applied.
How long after. Staining with a solid color stain can I put a sealer on it?
You cannot apply a sealer on top of a solid color stain.
We recently finished cleaning, sanding, and applying Thompson water seal to our 12 yr. old deck. It turned out great. This week we had a new patio and natural stone steps installed. Every thing is now covered in a thick layer of stone and paver dust. We have swept and hosed it off several times but soon as it dries, the film of dust reappears. Do you have any suggestions?
Try a deck cleaner to loosen up the sand dust so you can wash it off.
I live in Vernon British Columbia Canada. It's in the interior of BC. We get hot summers and cold winters. I have a new 10 month old deck, that has blue clay footprints on it. When this clay is dry it's like cement dust, when it's wet it's like a greasy clay. The deck is a hard wood deck, the wood is called Kaya. I was told to useTSP and water with a brush, then carefully pressure wash it. It did manage to get most of the dirt out, however the areas that had the most footprints still have the clay in the grain. I just managed to spread it around so you don't see the foot prints but the board still has the clay in it.
Do you have any suggestions for me?
Thanks
John, never heard of clay footprints. Have you tried a general degreaser cleaning solution. That may help. We have used concrete cleaner degreasers on wood for other things but with success.
What is the best method for cleaning railings/balusters/posts? Using the pump sprayer for the vertical balusters/posts is especially frustrating. Any other ideas?
Matt, pump spray on the cleaner then lightly pressure wash off.
Hi. We cleaned our treated wood deck with Restora Deck but it did not get out cherry stains that occurred before we could stain the deck for the first time. We did not put on the brightener thinking that we should try something else to get the stains out. Any ideas what to try? Oxalic acid wood bleach? Stain stripper? Should I try the brightener next?
Hi. We cleaned our treated wood deck with Restora Deck but it did not get out cherry stains that occurred before we could stain the deck for the first time. We did not put on the brightener thinking that we should try something else to get the stains out. Any ideas what to try? Oxalic acid wood bleach? Stain stripper? Should I try the brightener next?
Thanks.
BarbannT, I am not sure what will get out the cherry stains. The brightener contains some oxalic so you could try that. Stripper would not get it out.
I have cleaned my deck in Northern Virginia and frequent rain showers and our vacation have prevented me from staining it for nearly four weeks. Should I clean it again before staining, once I see a five day forecast that looks favorable for cleaning, drying, staining and stain drying (about five days of dry weather)?
Chris, I would do at least a light rinsing to get rid of any dirt and grim.
I keep reading conflicting information about the use of bleach as a cleaner to prep a deck. A guy I know who has being doing this type of work for about 10 years mixes 4 parts clorine bleach with 1 part Spic and Span to clean the wood before staining. He tells me he has never had a problerm with the stain peeling etc. What are your thoughts on this?
Larry, I am not a fan of bleach as it has been proven to breakdown the wood\’s lignin. I am sure an experienced contractor would minimize this with water and such so it may not have any damaging effect. In general though it never will clean as well as a good quality deck cleaner.