Tips & Techniques for Preparing Your Deck for Annual Maintenance

Assessing the Condition of Your Deck

How to Start?

The first step with annual maintenance is to take a close look at the deck's condition so you can decide first, whether or not to refinish, and second, what steps are necessary. If you are using a very high end finish such as our ExoShield, you may be able to get away with finishing every two years instead of every year.

This Cumaru hardwood deck shows some stains from where leaves sat on it over the winter - the deck was finished in August of 2018 with ExoShield Walnut. Color isn't horrible after almost two years but it clearly needs some cleaning. Photo taken in April 2020.

The key to this decision is how much color have you lost and do you have any serious dirt or stain left from leaves or other debris sitting on the deck over the winter. If the deck's color is still intact, a light rinse once all annual pollen has settled might be all you need to do. However, if the color is significantly faded, then you really should re-coat this year.

There's still decent color left on this deck and certainly no algae, moss or other unwanted growths. Again, this photo was taken in April 2020 and the deck was finished with ExoShield Walnut in August 2018.

Most cheap deck stains require at the bare minimum at least annual maintenance. This generally includes an extreme cleaning by pressure washing or sanding. Yes, this means all the way down to bright fresh wood. There's just no point in coating over a grayed out or silvered out deck. And if the previously used deck coating doesn't have a built-in fungicide, then you probably have the beginnings of mold, algae and more already growing within the wood itself. Using cheap deck stain creates a lot of work!

A lot of folks get fed up and tired of doing annual maintenance

It's very frustrating to put a ton of work into your deck only to have it look bad within a few months. This is the typical dilemma we hear from homeowners all the time.

One home owner put it the following way, "It's easier just to let it gray out." Yes, it is much easier but your deck will really start to look bad if you don't at least pressure wash it every few years. I ran across this lovely example a couple years ago.

Initially it was coated with Penofin in 2007, and believe me it looked GREAT in 2007. When I saw this deck it had at least 1/4" of growth of "something" - not really sure what you would call it... After pressure washing, the deck cleaned up nicely. It also opened up the wood fibers to accept the new ExoShield coating.

AGAIN, THE KEY IS BRIGHT FRESH WOOD. You want to lock in that beautiful color of natural wood and the only way to get it there is to get it clean - more on that in a moment. After waiting a week for the wood to acclimate again, we applied ExoShield and the results are magnificent.

What kind of finish have you applied in the past?

This will determine how to prepare your deck for refinishing. Hopefully, you know what kind of finish you have applied in the past. There are three general categories, Oil based, Water based and Film forming.

If you have been using an oil-based finish in the past, you can use another oil-based product in the future. Of course we recommend using the best quality finish available. Oil based finishes are NOT ALL THE SAME, but in general different brands of oil finishes are compatible with each other. If you are coating over a high quality oil finish on a once-a-year basis, you will not use as much finish. The wood just won't absorb as much if there is already some left in or on the wood.

If there was any sort of film-forming finish such as a spar varnish, urethane or polyurethane, then you will have to SAND IT OFF - sorry, so sorry. We never recommend film-forming finishes for exterior decking.

Water based finishes are a bit of a mystery. Some of them do so little to protect the wood that applying an oil the next year is no problem at all. Others actually have resins in them and can do a pretty decent job at holding color over time. These resins will absorb into the wood and won't allow subsequent oil-based finishes to penetrate very well, if at all. High quality oil stains also have resins which will penetrate and dry inside the wood itself. The experts all pretty much agree that oil-based stains penetrate better.

The bottom line: Oil-based stains are generally compatible with each other. Water-based stains that contain resins are complicated - deep cleaning, heavy pressure washing, sanding will be required. Film-forming finishes must be sanded off.

Deck Cleaners- which ones actually work?

On the subject of deck cleaners, they don't work very well. You still have to pressure wash or sand. The best one I have ever used is 30 Second Cleaner. It cut the time required to pressure wash in half and I was very impressed. It's the best product in its class, for sure. But it won't do the job by itself without pressure washing.

How to determine if pressure washing or sanding is best for your deck?

Ok, so you've used some deck cleaner and it didn't do much. Then you tried to pressure wash with a low cost 1200 PSI "pressure washer" and it's still gray. Now what?

You have two options: Pressure wash or sand.

If you have a hardwood deck such as Ipe, Cumaru, Batu, Brazilian Redwood, Tigerwood, Cambara, Mahogany / Meranti, etc. then you can use a high powered pressure washer that will run up around 2800 PSI. I always use a turbo nozzle, which is a pinpoint needle nozzle that spins really fast, but only when pressure washing hardwood.

If you're working with softwood such as Pine, Cedar, Redwood or pressure treated, then you can't use a high powered pressure washer without tearing up the wood. Start with low setting on the pressure washer and use a wide fan nozzle to prevent damaging the wood. Test very carefully. If light pressure washing on softwood doesn't do the job then your best bet is to sand the deck using a belt sander. You can rent one at your local building material center or big box store. You still have to be careful.

Let it dry out completely before finishing

In hot dry weather - say 70 degrees plus and direct sunlight - you can safely coat your deck the next day after pressure washing. But, you are better off to wait 3 to 5 days (or longer) so that all the water inside the boards has had a chance to evaporate. You don't want the water taking up space inside the wood fiber. Just because it's dry on the surface doesn't mean it's dry inside the boards. Your deck stain WILL LAST LONGER if you let the wood totally dry out. This also applies to coating the deck early in the year just after the rains have stopped. Give it a chance to dry out - you will get better results!

Finishing - The fun part!

I absolutely love applying finish - whether it's to my deck, a piece of furniture I built (or rebuilt), a musical instrument... This is the best part when you really get to see all the work that went into preparation. The culmination of many, many, many hours of work.

The finish itself makes the project look great. Take your time when coating your deck and follow all the manufacturer's instructions. If you are applying a wiping finish, you absolutely must wipe it down. I use an old beach towel and just walk it all over my deck. It's best to start wiping within 30 minutes of rolling out the wood stain.