Power Washing Cedar

[gusg]

Well I went and did what just about everyone told me not to do. I had the cedar deck that was put up last fall power washed in preparation for having its first stain. I had it done by a couple of guys who gave me a good price. They said they have done many cedar decks with no problems. The power washing didn't gouge the wood but it did take off some of the surface wood and now I have some fuzzy looking white stuff all over the deck. They said it will be no problem once they put on the stain. The neighbor said he sanded the whole deck after doing the same thing.

Did I screw up the deck? I am hoping that the guys are right and it will look good after the stain is applied on Monday.

 

[beenthere]

How old is the deck? i.e how long has it been exposed to the sun?

 

[gusg]

The deck was put up last October and then waterproofed. It has sat in that condition until now. So it has seen one winter and has been up about 9 months.

 

[beenthere]

My first thought was the fuzziness was the result of the UV rays of the sun, degrading the surface of the wood and thus leaving the 'cellulose' behind after power washing. That would be an expected result. However, with just a short time since building the deck, I suspect the fuzziness is caused by the power washing being a bit too aggressive on the soft cedar wood. My suggestion would be to put a finish that you plan to use on just a test area and decide if sanding will be necessary before applying all the finish. Scraping with a sharp edged scraper may cut the loose fibers off too. Regardless, I would be sure the finish is what you want before letting them do the entire deck. Likely all that was needed was a deck cleaner to loosen dirt and early stages of mold, and then rinsed off with water from a garden hose. Power washing is good for getting rid of loose paint and pigment, of which your deck had none. Wish you good luck getting what you want.

 

[Ozarker]

The fuzzyness is damage to the wood caused by too much pressure from the power washer. I have two cedar decks, one front and one rear. They are both 15 years old and I power wash them every spring. No fuzzys..................

 

[Scott_in_WVA]

They probably used the wrong size tip on the gun.

 

[webbmeister]

When using water-borne finishes in woodworking, I often come across "raised grain," a result of water being applied to wood. Raised grain results even from gentle application with a brush or sprayer, and it is necessary to lightly sand the work to eliminate the "fuzzies."

Power washing, I would imagine, would raise grain to a much greater degree - perhaps tearing the fibers as they are raised. In either case, I believe it would be unwise to apply stain, oil, or a film surface before sanding away the fuzzies. The grain that is raised is very likely to soak up more of the finish than the rest of the stock, and you'd probably end up with a deck that looks splotchy and streaked.

To make life easier for yourself, you might consider renting a floor sander. The vibrating type would be more than agressive enough to take care of your problem. The drum type takes some practice to avoid gouging the surface.

Sorry you're having troubles.

Jim

 

[beenthere]

Good thoughts about the deck boards and what to do. Problem I see with machine sanding is the likelihood that there is cupping in each deck board. It makes it difficult to take an even 'cut' across the surface of the board. It may work, and it would be the easiest fix if it does.

 

[Ozarker]

No doubt. My pressure washer has a tip that allows me to fan the spray and reduce the velocity of the water. I set the pressure on a piece of scrap pine first, then I clean the deck.

 

[webbmeister]

Good point. Well, it's a big step closer to misery but a hand sander outfited with a thick sponge rubber pad made for contour sanding and some light weight sandpaper plus knee pads and plenty of cold beverage will get you through the cupping/profile problem. Just be sure to consume the cold beverage evenly across the entire job so you don't wind up with a mess at the end.

Jim