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Is there any maintenance that I should be doing such as yearly power-washing and water-sealing for a pressure treated deck?

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I've been reluctant to power wash my deck, as if done incorrectly (too much pressure, wrong nozzle), you can damage the wood. Unfortunately, scrub brushes and/or a lot of time w/ a belt sander mean I don't end up doing anything. (so I'd love to hear if there are other alternatives) – Joe Oct 27 '11 at 19:44
is your deck stained or natural finish? Does the sealant you used last year still beading water? – shirlock homes Oct 27 '11 at 20:18

It's always good to inspect your deck every year after winter. Check for any loosening fasteners, any signs of rot, check for mold, and inspect places where wood meets wood.

I would advise against an annual power-washing. It is extremely harsh on the wood, even if done by a professional. It requires a lot of work to restore the surface, as the pressure washer damages the surfaces. I would look it at as something you do to restore an old deck.

It's usually a good idea to give the deck a gentle yet thorough annual cleaning to remove any built up dirt. If you see mold forming, it doesn't hurt to use some bleach. I'd try to do it when you have stretch of good weather so it can thoroughly dry, but avoid doing so when it's so hot that the water dries before you have a chance to rinse the cleaning solution off.

Trimming back any bushes and growth near the deck before this step is also good, as it ensures the deck can dry properly.

When it rains, see if the water is beading and running off properly. If it's not, then you should consider re-sealing the deck. It's not uncommon to hear suggestions of an annual application of water sealant. I don't think it's necessary unless it's a particularly expensive deck, or your region has a climate that's harsher on the deck.

For the late fall, it's a bit late in the season and you may not get the right conditions. I'd still do a complete visual inspection. You can do spot treatments to hold you over until spring. Clean any mold spots. Clean any areas of rot, allow to dry, and then spot treat with sealant. If water is pooling on any boards, consider spot treating there.

(Also, pressure-washing and resurfacing are a lot of work, and there is a lot of room for error. Make sure you're careful to do it right.)

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So it can be a good idea to water seal wood even if its pressure treated? – Michael Pryor Oct 30 '11 at 1:58
Yep. Some seal products vary as to when they recommend a first application depending on how new the deck is. If it's been a year or more, I wouldn't worry about that though. – Hemm Oct 31 '11 at 6:36

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