I saw many videos on Youtube of people renewing their decks doing a pressure washing, applying a cleaner to revive the deck and then applying the stain or sealer for old decks. My BMR treated wood is totally new and recently installed just a few days ago.

Do I need to applying pressure washing and a cleaner prior to seal my deck? or can I go stain and sealer it right away (if dry)?

EDIT: Picture added

This is the picture of my new deck in Quebec. I was wondering after sharing this image if the cleaning is just necessary. I heard that cleaner smells like bleach and I installed a pond liner below to divert the water away from my foundation. I received this stock of wood a couple of months ago was brown and wet. Then rain hit it and during installing some screws showed that the core was wet yet. After being an intense heat these days over 30C degrees I can see they changed their color to pale and started to shrink, because I installed the deck boards with just more than 1/8 in but now it looks like a 1/4 in gap.

enter image description here

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    If "BMR" treated is similar to "Pressure Treated" (i.e. chemicals soaked into the wood to reduce the rate of rot), then you should probably let the wood dry out before attempting to seal it. PT lumber is often very wet and sealers don't work well on wet wood.
    – FreeMan
    Jul 18, 2022 at 11:42
  • Yes, it is pressure treated wood. I just edited my post to include a picture a give an idea of the cleaness of my wood. Jul 18, 2022 at 14:16
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    When we installed our deck, it was recommended that we wait 3 months before sealing it to allow the wood to dry out. Can't tell by looking at it if yours is dry enough or not, but you're probably really close. Once you're ready, I'd just give it a light clean, if anything, to ensure that dust, leaves, pollen, etc. are gone, then seal.
    – FreeMan
    Jul 18, 2022 at 14:31
  • Thanks for sharing your comment. That is what I was thinking of. They look clean and a light cleaning maybe would be enough instead of using any other bleach chemical cleaner since they are new. I will wait some weeks, will sand it with a 220 grit sand paper just to make it smoother and start staining it and sealing it! Jul 18, 2022 at 19:00
  • I like the color and would vote for not staining. / Last summer there was a lumber shortage in my region, and the pressure treated lumber I bought for my raised vegetable beds was wet. The lumber had not been left to sit for 3 months before being put on the racks for sale. Jul 20, 2022 at 6:18

1 Answer 1


When we installed our deck, it was recommended that we wait at least 3 months to let the pressure treated lumber dry out before applying any coatings. After ours had dried, we applied a clear(ish) sealer. (We did actually pressure wash the deck because it wasn't until the next spring before we got to sealing it, but would not have had we done it the fall before.)

It's hard to tell from a picture whether yours is dry enough, but if the lumber was sitting for a couple of months prior to construction, it's probably close to dried enough. I'm not sure if there's an exact science to it, but I'm sure you could pick up a wood moisture meter to determine exactly how wet the wood is. I'm sure that would also be overkill.

Since your deck is, essentially, brand new, I'd suggest nothing much more than a light cleaning (leaf blower, broom, then a scrub with a broom on any stubborn spots) to ensure that leaves, footprints, general grit and grime, etc are removed, then follow the instructions on your can of sealer for the number of dry days prior to and after sealing, to ensure you get a good application.

As to your comment about sanding the deck, unless you're planning on walking on it barefoot all the time, sitting bare legged on it, or you've got some really rough areas that are splintering, I don't think sanding would really be necessary, especially not to 220 grit. If there are a couple of rough areas, I'd suggest tackling just those rough areas and not plan on sanding the entire deck. Unless, of course, you just really want to. Don't forget, this is going to be exposed to the elements 24/7/365 and will not be perfect again within a week.

  • Are you from Canada? Which sealant did you use? Was it good? Jul 19, 2022 at 18:48
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    I'm in the US. I believe it was Thompson's Water Seal. 3 years of Midwest summer rain and winter snow and water is still beading on the deck, so I'm not complaining.
    – FreeMan
    Jul 20, 2022 at 11:20

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