8 Reasons Deck Stain Peels and How to Prevent it

A few days ago, I had a customer call me to take a look at their deck. They had hired a paint company a couple of years back to “stain” their deck with a solid wood stain, and it was peeling and flaking off. Making their beautiful outdoor space less than impressive. It’s incredible how a little flaking will ruin beauty. Three cheers for dandruff shampoo!

Back to the deck issue, this is what drove my research. What was causing his deck stain to peel? What causes any decks’ stain to peel and more importantly, what can we do to prevent deck stain from peeling?

Lack of stain penetration is the number one reason deck stain peels. Poor stain penetration is a result of over-application, poor adhesion and incorrect deck stain. Another cause of deck stain peeling is high moisture content of the wood.

Wood decks are great for both their price and look. No decking can compete with wood decking’s economics but its greatest weakness is staining. Wood decking needs regularly stainingOpens in a new tab. to maintain its beauty and value. Stained correctly, wood decking will last as long as synthetic decking. But it’s essential that the stain does not peel. Peeling deck stain destroys all its value, by not protecting the wood and making the deck, to put it plainly, UGLY.

These questions are driving my research.

Why causes deck stain to peel?

What can be done to prevent deck stain from peeling? The most important question.

And finally, rehabilitation of a peeling deck. Once we know what went wrong, what steps need to be taken to restore your deck to its original beauty with stain lasting for years.

8 reasons that deck stain peels.

  1. Excess moisture
  2. Excess stain
  3. “Green Wood”
  4. Improper wood pH Balance
  5. Staining in the hot sun
  6. Not working the stain into the wood
  7. Staining over failing stain
  8. Incorrect sanding before staining

Not allowing the deck to dry sufficiently before staining.

Exterior stain often peels because of high wood moisture levels, either before or after staining.

“Wet” wood absorbs less stain. Decrease level of stain causes the stain to break down and peel prematurely. The stain is just not thick enough to hold itself together. The deck must be allowed to dry before staining, both after construction and cleaning.

Decking is kiln dried to 19% at the mill. A lower moisture level absorbing stain better. Also, decking often gets rained on during transportation or storage. Wait 3-12 months after construction before staining the deck. Yes, I know you are eager to finish your deck and set up the deck furnitureOpens in a new tab., but it will be better to wait till spring after your deck has had a season to dry and climatize.

Not requiring as much time, but after cleaning, your deck should dry 1-2 days before staining. Spray, wash and sand it down as you need to before staining and then give it a couple of days to dry out again. Drying the deck out thoroughly to absorb the most stainOpens in a new tab. possible.

Over application of deck stain.

Excessive stain can also cause moisture issues resulting in peeling stain peel. In the words of Steve Maxwell.”Don’t coat more than twice since too much deck finish can encourage peeling by trapping moisture in the wood. Over coating is a common cause for deck finish failure.”

“Don’t coat more than twice since too much deck finish can encourage peeling by trapping moisture in the wood. Over coating is a common cause for deck finish failure.”

Steve MaxwellOpens in a new tab.

Yes, you can have too much of a good thing. After every snow or rain, the deck needs to dry out. When the sun comes out, evaporating the water in the wood. Too thick of stain will prevent the moisture from evaporating through the coating. Becoming most evident in springtime as the wood has become waterlogged through the winter. The trapped water peeling the stain of the wood. The problem is more significant with solid stains, but we will get to that more later.

Think of it like a river. You can dam a river, controlling its flow, but you must be allowed to flow. If you block the water entirely, the water has no choice but to blow the dam. Damaging everything around it. The same is true for your deck stain.

In-Sufficient Under Deck Ventilation.

Not really an issue for higher decks, but decks lower than 24″ (0.6m) from the ground need air movement under the deck to allow the underside of the decking to dry. A lack of ventilation for a lower deck increases stain peeling. Similar to over application of stain, blocking the decking from breath and releasing excess moisture, the same is true for the underside of the decking. Wood needs to breathe, both the top and underneath.  

Insufficient ventilation will create a humid environment under the deck and decking. This trapped moisture under the deck will be absorbed through the underside of the decking. Will try to escape through the top of the board. But the excessive level of moisture will exceed the stains capacity of releasing water, breaching over the dam in our analogy. Cracking and pushing the stain off the decking to allow the moisture to escape. A vent under the deck would work much better without peeling of the stain.

To learn how much a deck needs click hereOpens in a new tab. to read about deck ventilation. It’s surprising how important ventilation is required to maintain deck health. We all need to breathe including your deck.

Poor Stain Adhesion causes deck stain to peel.

Becoming increasingly more common, with increased regulations restricting VOC (Volatile Organic Compound). With manufacturers changing their formulas or switching from solvent-based stains to water-based stains. Helpful in reducing the environmental impact of stain and lightheadedness while staining but at a price. Increased stain peeling as they try to figure out the correct formula. Trial and error, taking place till they figure it out.

Like Velcro, the stain must stick to the wood. Adhesion achieved by the stain penetrating the wood. If the stain is unable to penetrate the wood, it will not stick. Like Velcro, the deeper the penetration and the more entwined the stain becomes with the wood, the lest it will peel.  Here are a few ways to increase stain penetration.

Allowing the deck to weather before staining.

Not only does the sun dry out the deck increasing its absorption capacity. But the sun and wind also break down the surface fibres of the wood, opening the wood pores to receive the stain.  

Believe it or not, wood wasn’t made for decking but was part of a living organism. Each wood cell is acting like a small sealed cistern holding water for the leaves. Closed preventing stain from getting in until the sun opens them ups to receive stain. Think of it as a million juice boxes, and the sun poking straws into every box, allowing them to drink up the stain. That’s what climatizing the wood does. The sun opens the surface wood seal.

Clean and Brighten Decking Before Staining

Not only does brighteners make the wood look better, but it also opens the wood pores. With the wood pores open more stain can be absorbed.

Back to our juice box analogy, brighten chemicals are like soap to wash the straws out, unplugging them for the stain can get in. Doing more than just power washing, which needs to be done. But power washing is only cleaning the out of the “straws” not opening them up. The deck needs to be clean and brighten before staining.

Deck brighteners also neutralize cleaners and strippers. A high pH level from cleaners prevents the stain from adequately adhering to the wood. It the words of a Jedi master, you must “bring balance to the force.” Not only a galaxy far, far away but also a deck close by.

Remove excess stain while staining your deck

Excess stain not only traps moisture causing peeling but applying more stain than the wood can absorb, causes the stain to film over. Excess stain filming over and suffocating the wood resulting in the stain peeling.

Inside furniture, a glossy layer of stain may look great, but decks outside needing to breathe and adapt to their environment. The film prevents the decking from breathing and adapting. In desperation, the decking pushes the stain up, peeling in an attempt to breathe. A shirt protects you from the elements, but a plastic bag is uncomfortable. The same is with your deck. A thin layer of stain protects and lets the wood breath. A film of stain becomes uncomfortable, forcing the wood to peel it off to breathe.

Never Stain your Deck in Hot Sunlight

Direct sunlight and the heat of the day causes the stain to evaporate too quickly, preventing sufficient penetration. The stain merely sitting on top of the wood. Stain your deck while it’s shaded or in the cool of the day, gives the stain enough time to penetrate the wood. The longer the stain can penetrate, the deeper and more durable the stain will be.

Stain your deck using a natural bristle brush

I have seen it all, sprayer, rollers, pads and brushes, but the best of these are brushes. The bristles, moving back and forth, massaging the stain into the woods opening. Who isn’t more agreeable after a massage? The bristles also push the stain into small crevasses and cracks in the wood.

Yes, spraying and roller are faster than brushes, but the quicker on, the faster off. Without the bristles working the stain into the wood, the stain remains only on the surface with less adhesion.

You can do a combination with a buddy. One of you rolls or sprays on the stain speeding up getting material unto the deck, with the other back brushing, working the stain into the wood. However, you get the stain on the deck. It needs to be worked in with a brush to decrease peeling.

Completely remove the previous coating of stain before applying new stain

Many stains will not adhere to different brands or types. Whenever you change brands or types of stain, always remove all the old stain completely. Allowing the new stain to penetrate and adhere to the cellular structure of the wood. Otherwise, you will just have a surface level of stain, which easily chips and peels.

Sand the deck with the correct grit level to prevent Peeling

I write this with shame. In my zeal to do an outstanding job, I have sanded decks with to fine of sandpaper closing the pores preventing the stain from soaking into the wood. Yes, sanding is excellent for removing the old stain, smoothing and opening the wood pores, but over sanding prevents adhesion of the stain. Start with a 36 grit to remove the bulk of the old stain, move to a 60 and finish with an 80. Anything finer than 80 grit will start closing in the cellular composition of the wood, keeping the stain merely on the surface. Surface staining is peeling staining.

Here is a video going through all the steps of sanding a deck, starting rough and progressing.

Rehabilitation of a Peeling Deck Stain

In short, the stain is failing and will need to be replaced. All of it. If the stain was not peeling a simple cleaning and staining as regular maintenance would be an option. But not if your stain is peeling, any stain applied over failing stain will only fail. It all must come off, removing all the stain down to clean wood. I cannot emphasize this enough. Your stain has failed and must be removed. It is mind-numbing hard work, but for the new stain to adhere properly, it must be correctly applied to clean wood. The old stain must be removed entirely.

I hope you noticed off our list of reasons stain will peel most have to do with preparation. Prepping a deck for staining is the longest and hardest part but is the most essential. If you get this wrong, it doesn’t matter what stain you use. It will fail. Sending you right back to staining your deck prematurely all over again. Take your time, follow each step, do it right, and your stain will enhance your deck for years to come.

As an aside, this is the reason that Jeff from Home RenoVision DIY on youtube recommends just going with a Thompson Clear sealerOpens in a new tab.. The hard work is in preparation for staining. Simply cleaning and sealing your deck each spring is easier than the preparation required to stain a deck correctly.

That being said, either way, that peeling deck stain needs to be removed before you stain or seal your deck. It’s ugly and has failed and needs to go.

Stripping your deck and preparing it for staining will require the use of lots of chemicals which benefit is limited with heat. All staining and deck preparation should be done on a cool day or early in the morning for the sun doesn’t out work, all your hard work. Pick a cool, overcast day with no forecast for rain to start, ideally with warm days following to dry your deck before staining.

Following are some quick videos of Russ Olinatz going preparing and staining a deck. But here is a quick outline of the required steps.

10 Steps for Restaining Your Deck

  1. Empty your deck
  2. Sweep off all debris
  3. Protect your house and yard surrounding deck
  4. Pressure wash or scrub with a stiff brush and cleaner
  5. Use striper to strip off the stain
  6. Using deck brightener to balance the wood before staining
  7. Sand deck as required, remember nothing finer than 80 grit
  8. Allow the deck time to sufficiently dry
  9. Apply a maximum of two coats stain
  10. Allow the deck to dry before enjoying, and placing your furniture back on

Listen carefully to Russ. He has some really valuable gems of information on doing it right. Both in practice and theory. I watch a lot of videos till finally finding him and his depth of knowledge. A lot of people just skip over the finer details or focus on the power washing, which is fun to see with a dirty deck but missing out on the details that make the difference.

Russ discussing the required tools and steps.

Russ stripping and power washing off the deck

Russ brightening, rinsing and sanding off the deck

Russ staining the deck

A Few Final Words on Deck Stain

Preparation of your deck will do more for preventing the stain from sealing than anything in the can. You have failed or won before dipping your brush in the can, but if you go to all that hard work, get the right product.

  1. Quality is costly. The chemicals that make excellent stain are expensive. The easiest way to reduce cost is to skim on these chemicals that make the stain work. If its “cheap” its “cheap,” your receipt already told you if it’s going to last.
  2. Penetration is critical. You want stain that will soak in and become part of your deck, for it can’t peel off.  Your looking for all that nano and micro working technology. The more it becomes part of the wood the better. It’s called “stain” for a reason. If it’s not staining your deck, what is it doing?
  3. Transparent deck stain is better than solid. I have heard much claiming that “solid” is better and will last longer. But the simple fact is that it films on the top and is not penetrating. Semi-transparent may be the best of both worlds, offering more colour and protection while still penetrating, but it must penetrate. No Adhesion=Peeling

Beyond that, it’s a matter of deck brandsOpens in a new tab. and formulas, which would be another article entirely. Prep well, my friend, don’t skim, and it will be worth it, your deck will look fantastic for years to come. Enjoy your outdoor living space.

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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