Why Does My Deck Stain Look Milky? (How To Fix This Issue)

Few things are as frustrating as putting a fresh new stain on your brand-new deck only to come out a day or two later and see your beautiful finish marred with milky streaks.

On the one hand, sometimes these milky streaks in a deck stain are signs that the stain hasn’t yet “cured”. Those kinds of streaks disappear in a couple of days. On the other hand, though, moisture can become trapped underneath that stain or sealer. Those streaks can be a challenge to get rid of.

Armed with the inside information below, though, you’ll be able to resolve these milky stain deck issues without a lot of headache and without a lot of hassle – no matter what caused them in the first place!

Why Does My Deck Stain Look Milky?

As highlighted a moment ago, there are really two main reasons your deck finish might look a little “milky” a couple of days after application.

The first reason is pretty common, especially when you are using a water-based stained – especially if you are using a water-based topcoat on top of a oil-based stain product.

At first contact, the finish is going to look absolutely crystal clear and picture-perfect.

You’re going to be applying the finish, everything is going to look great, and your deck is going to appear to be the deck of your dreams. 24 hours later – or maybe even faster than that – your deck looks like someone spilled a couple of gallons of milk all over the place, though.

Give It Time

The best thing you can do in this specific situation is simply give the finish a little more time to sort itself out.

It’s probably not going to take much longer than another 24 to 72 hours for that finish to fully cure, harden, and all of those milky spots to disappear once and for all.

The second reason that you might see a milky finish, though, is a little more problematic and not something that time is going to sort for you.

No, when you have a milky finish caused by moisture getting trapped between either the raw wood and the stain you are using (or individual stain layers) you’re going to have to use a little bit of elbow grease and some ingenuity to get things looking crystal clear again.

Worst of all, it doesn’t take a whole lot of extra moisture to cause this milky appearance either.

Applying the stain on a particularly warm day with a chilly night that results in morning dew being left on the deck surface before you apply another coat of stain is enough to do the trick.

How To Solve This Second Issue

You have to be absolutely, positively certain that your deck is dry as a bone before you apply that first level of stain. And it needs to be just as dry (and the first coat of stain fully hardened and cured) before you add any other layers, too.

How to Prevent “Blushing”

This milky appearance is called “blushing”, and it’s a more prevalent problem that even professional deck builders and finishers have to deal with than most people expect.

Any water that dribbles into a stain – even the smallest amount of moisture, as we just highlighted a moment ago – as it dries and cures runs the risk of leaving behind this milky residue.

Adding the water-based topcoat on top of a wood stain (especially a water-based topcoat on top of an oil-based stain) causes the problem, too.

This is because the oils in the wood stain end up forcing themselves into the water-based topcoat while you brush it on (or spray it on), creating that moisture mixture that wreaks so much havoc.

The best way to avoid this blushing in the first place?

First, make sure that you have a couple of days of nice and dry weather out of you before you decide to apply any stains to your deck.

A three-day sequence of reasonably warm temperatures without any rain in the forecast is a long enough window to get this job done and get it done right.

Secondly, if you plan on using a water-based topcoat on your stain you need to be sure that you are using a water-based stain underneath as well.

Mixing and matching and oil-based underlayer and a water-based topcoat is a surefire recipe for disaster.

How to Fix a Cloudy Deck Finish

Well, there are a couple of ways you can fix a milky finish on your deck – and all of them involve a little bit of elbow grease.

Strip the Milky Spots

First, you could do a quick “spot strip” with a little bit of steel wool, some mineral spirits or some cut paint thinner, and some old T-shirts or rags.

Get down on the spots that are milky, scrub them with the steel wool, so, little bit of mineral spirits to remove the topcoat, and then rag everything off. Once you are completely dry you can reapply the topcoat to seal things back up again.

Total “Tear Down”

Another option is to get your hands on some steel wool, plastic scraper, and a couple of different levels of sandpaper as well as a random orbital sander or a belt sander – particularly if you want to speed the project up.

Go to work sanding, scraping, and steel wooling the entirety of the deck to get that topcoat up and to prep the underneath (already stained) surface.

After you have all the stain removed and all the milking this eliminated you can prep the surface for the stain you’re going to use, re-stain, and then re-seal the deck once again.

Closing Thoughts

A cloudy finish can really ruin an otherwise beautiful deck – and the worst part is it is (almost always) 100% avoidable.

Take advantage of the tips, tricks, and inside information we highlighted above to avoid this milky finish from taking hold on your deck in the future.

The only thing worse than having a stain finish on your deck go sideways once is having it happen over and over again.

With the details above, though, that’s never going to be a problem again!

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Why Does My Deck Stain Look Milky? (How To Fix This Issue)