Hot Topics: Sand or Pressure Wash Before Staining a Deck?

A woman pressure washing a deck.

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When you want to stain an older deck, you have to properly clean the surface. It's important to know whether sanding or power washing will yield the best results to properly stain. Read on to see what these avid DIYers recommend.

Original Post: Question About Deck Staining Procedure

Jason Niu Member

Hello deck pros -

Question about the procedure on properly staining a deck. Lots of online guides state that one should wash the deck with wood cleaner or brightener prior to staining, but do I still need to wash the wood if I am going to sand the whole thing? Doesn't sanding remove all surface impurities, mold, or oxidization?

Highlights from the Thread

marksr Forum Topic Moderator

Other than to repair areas that were washed overly aggressively - I've never sanded a deck. The nails/screws will eat sandpaper in short order! Is there a reason you want to sand rather than clean?

To answer your direct question, no you don't need to clean the deck if all the wood is sanded down to raw wood. You would need to remove the sanding dust.

XSleeper Member

I would power wash the deck then sand it lightly to smooth out any fuzz. Sanding alone will take forever and a day, and you won't be able to sand around balusters and such, so you might as well power wash it all to get all the nooks and crannies... and no, sanding won't remove everything. Plus sanding paints, stains, and finishes is never a good idea because you can inhale hazardous chemicals/substances - says so on almost every paint can. A little bleach (25% is a good ratio to use) will help brighten the wood, which is important if the finish will be transparent or semi-transparent.

stickshift Group Moderator

I'm with Mark, I'd clean the deck.

I bought my house new from the builder with a cedar deck attached. Builder claimed he was going to come back and seal the deck, but he never did. By the time I figured out he wasn't coming back, the wood was almost black. I cleaned it with a 50/50 bleach and water solution, and it was almost back to new. Cleaned it one more time and the wood was blond. After staining, a couple of my neighbors came by and told me I had gone from the ugliest deck in the neighborhood to the best looking one. I did not sand anything.

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