Today’s wooden decks (especially those built quality pressure-treated materials) can last 10, 20, 30 years or more before key parts have to be replaced. That usually means you’re going to have to re-stain the deck at least once or twice.
The good news is you don’t have to worry about what kind of stain was put down on your deck before when you put a new coat on. You can use oil based deck stain over water based deck stain without any headache or hassle at all!
There are some things you’ll want to do to prep the surface of your deck before you restain everything. That’s for sure. But we point you in the right direction for all that in this detailed guide.
Can You Use Oil Based Deck Stain Over Water Based?
The stain and sealer that you apply to your deck is its first line of defense against Mother Nature.
This outdoor structure is going to be subjected to all kinds of wind, all kinds of weather, and some pretty nasty conditions that can change on a dime. Combine that with the beating UV rays of the sun, major fluctuations in temperature and humidity, and you’re working with a recipe for disaster.
Well, unless you stay on top of your stain and sealing schedule, anyway!
When it comes to deck stain you really have two different choices to pick from. One is oil-based stains and the other is water based stains.
Both of these options have their pros and cons. Both of them can (for the most part) be used interchangeably with one another.
If you are going to use one stain on top of the other, though, it’s important to make sure that you are putting oil-based stain on top of the water-based and not vice versa.
Oil Based Stains 101
Oil-based stains are typically a bit easier to apply than water-based, have great longevity, and can be “touched up” without a lot of headache or hassle.
The finish does fade away over time. So if you’re looking for something that is really vibrant you might even want to be on an annual re-staining schedule with oil-based products.
Oil stains are beloved for their even finish and the fact that it’s almost impossible to generate lap marks when you brush or roll this on. The dry time does take a little bit longer, though, but that means it’s easier to blend the finish as well.
Oil-based stains are going to penetrate wood into the deepest fibers, even when you are talking about pressure-treated materials. That’s an extra layer of protection that water-based options generally don’t bring to the table.
Water Based Stains 101
Water-based stains, on the other hand, are going to last a little bit longer than oil stains thanks to the significantly better UV protection they have to offer.
On top of that, would based stains aren’t going to provide fuel for mold, mildew, and other fungus like oil stains might. Cleanup is simple and straightforward, dry times are pretty quick, and you’re not going to trap a lot of moisture in the wood.
Oil Over Water
Why is it so important to apply oil-based stains on top of water-based stains and not vice versa.
Well, it all comes down to the kind of finish that you get if you get this order of operations right (or if you get it wrong).
Let’s say, just for the sake of argument, that you’ve decided to reverse our advice and put a water-based stain on top of an oil-based stain.
The first day your deck might look spectacular. Water-based stains have that beautiful, vibrant finish and your deck is going to look picturesque.
The next day, though, it’s going to be a completely different story.
The compounds in the oil-based stain underneath are going to negatively react with the water. They are going to try and push themselves up to the top layer, and along the way they are going to cause a milky kind of complexion in the stain itself.
This is called “blushing” and it’s an absolute nightmare to try and get rid of.
If you took our advice, though, and did oil-based stain over a water-based stain this problem doesn’t happen at all.
Not only are you not going to trap any excess moisture in the wood that could cause the finish to be milky (water-based stains “breathe” and expel all that moisture before the oil goes down), but the water isn’t going to want to force itself through the oil finish, either.
It’s going to be locked in place!
This is why it’s mission-critical you get this order right.
Oil over water ALWAYS!
You’ll be a whole lot happier with the results.
The Secret to a Perfect Finish is Prep Work
Those looking to get a perfect finish on their deck aren’t just going to want to remember to put oil-based stains on top of water-based ones (not vice versa), but are also going to want to make sure that they are prepping their deck surface for the staining in the first place.
Far too many deck owners slap a little bit of stain on the deck every year (or every other year) without any real rhyme or reason, scrubbing or rolling it all over the place – or maybe even spraying it down with a garden sprayer or a compressor based system.
That’s a fast ticket to uneven finishes, dirt, dust, gunk and grime getting trapped between the stain layers, and all kinds of moisture getting “baked in” as well.
Instead you’ll want to blast the deck with a quick pressure wash, getting all that surface stuff off as best you can.
If you want to go crazy you could also do a quick (and gentle) sanding all over the surface of your deck, knocking down high spots and rough spots and also preparing the surface for better stain adhesion.
Give the deck a couple of days to dry completely – two or three if you can – and then (and only then) dive in with your oil-based stain.
You’ll love the way things finish out for you!
