Can You Apply a Clear Sealer or Polyurethane over a Deck Stain?  4.9/5 (463)

This post was updated on May 1, 2024

Clear Sealer or Poly over a Deck Stain?

We here at DeckStainHelp.com thank you for your continued support as we continue to be the internet’s number one reference for all things wood deck restoration related. If you have ever considered using a polyurethane coat to give your outdoor wood deck a smooth appearance, read this article and really think about the potential repercussions. As always, we appreciate your input, so feel free to leave a comment below.


Peeling Deck Varnish

Peeling Deck Varnish

Deck stains are meant as a protective finish for exterior wood. They contain special UV shielding pigments and mildewcides to ward off mold and mildew and to keep the wood from fading. Other sealers or clear finishes will not adhere well to a deck stain and may result in the topcoat failing prematurely. Most likely the clear sealer or polyurethane will end up peeling and flaking off the deck stain.

Unlike paint, stains and sealers are not necessarily designed to adhere to each other. Most are designed to penetrate into the wood or at least adhere to the bare wood in the case of film-forming stains. Applying a clear sealer over a deck stain is never a good idea. It really won’t help the deck stain or give any added protection more than the deck stain already is. Clear sealers have no pigment and therefore provide zero UV protection. The same goes for polyurethane.

Peeling Polyurethane Deck

Peeling Polyurethane Deck

If you are looking for a more shiny finish on your exterior wood surface, it is best to choose a deck stain that will give you the appearance you are looking for. Applying a clear sealer or polyurethane over a deck stain will cause more problems than it is worth. If you want a clear finish then you can strip off any old stain and start fresh with bare wood. Then you can apply a clear sealer if that is the look you are going for. Just remember that you won’t get any UV protection from a clear sealer, only water protection.

In addition, applying polyurethane over a deck stain will make it near impossible to maintain the deck down the road. As the deck stain begins to fail underneath the polyurethane it won’t be possible to clean and recoat it without stripping off all the polyurethane first. So can you apply a clear sealer or polyurethane over a deck stain? It is not recommended and should really be avoided if possible.

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Scott Paul ~ Restoring Wood & Decks Since 1993 Owner
As an article and comment contributor to the site, Scott has been around the pressure washing industry since attending college. In 1993 he started his first company called Oakland Pressure Wash specializing in exterior pressure washing and deck staining. That company evolved into OPW L.L.C. shortly thereafter concentrating more on exterior wood and deck restoration. Scott and his Deck Cleaning Michigan company have restored over 10,000 decks in the Metro Detroit area since the early years. He has become an authority in the deck restoration industry and has contributed to numerous wood restoration forums and informative sites. All the products he suggests through this site are sold through online sites and in retail stores, allowing the consumer to choose their own means of purchase. Scott’s eCommerce sites do sell many top brands he endorses and if you appreciate any of the help he has offered then feel free to purchase from one of them.

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Rosie Mallon
Rosie Mallon
7 months ago

I want to stain and protect my barn that was recently built. It is rough cut pine It has been weathering since June. Do I have to do the whole cleaning and brightening process? Would love to spare the extra work. I planned on using a penetrating oil based semi transparent stain. What product works best on vertical wood? Any opinions on Ready Seal 510 Exterior? Much thanks!

paul
paul
7 months ago

I have solid Acacia steps with an anodized clear satin finish (exterior, little to no sun with occasional light rain) that are generally in excellent condition, but after 2 years, I have a couple of very minor scrapes and I would like to recoat them with something just as bullet proof without having to take them all the way down to bare wood. Any ideas? Also in another few months, I will be putting down a deck made of red cedar with a clear penetrating oil – any ideas for a protective coating/sealer to go over that oil would be appreciated too. Thanks!

Liz Davis
Liz Davis
7 months ago

I want to faux paint my covered deck. I would use a solid deck paint and then apply glaze and wipe it down to resemble wood grain. I will need to put on a clear topcoat. What product do you recommend?

I have done this technique on wood garage doors with great success. Just not sure about a good sealer you can walk on for the deck.

Tom pawlowski
Tom pawlowski
11 months ago

We had a front porch installed last end of September early October. It’s all yellow pine . I want to apply a sealer. The one guy I talked to told me to wait about 3 months before I stained it . I guess to let it weather. Now it’s June. I am in Chicago and it has been very hot. I spray it down to cool down the porch and put life back into the wood . We have direct sunlight from 12:30/1:00 pm until 8:00 or so. My question is what kind of clear sealer can I use. And what else should I do to prep the wood before sealing.

Scott E.
Scott E.
11 months ago

I stain my decknwith a semi transparent stain last year , is the a clear stain that you can put over it

Frances Yaste
Frances Yaste
11 months ago

can you mix clear olympic summit stain with olympic summit mahogany blaze and will it adhear

Chuck
Chuck
11 months ago

Scott, My deck was re-stained about 4 years ago and needs to be done again now. However, I love the weathered look of it as it is. Can I put a clear finish on it like it is to protect the wood and keep the look?
The stain that’s on it is an acrylic PPG product called Flood pro series. What do you think?
Thanks,
Chuck

Dee Rogers
Dee Rogers
1 year ago

Hello Scott, Our deck is 20 yrs old, made of Pau lope wood. It is grey and weathered. Last year my husband had it power washed, it looked nice for a few months. We have only lived here 4 yrs so I don’t know what was done prior. Please help there isn’t anyone in our area that does this sort of restoration. My first question 1.) Is “Restore A Deck” the best product for us? 2.) Do I need to clean the Pau lope decking before applying (power wash?; to get off some black stains on railing?) ? I really believe this deck could be beautiful with the right help.

Richard Peck
Richard Peck
1 year ago

Hi. I have a redwood table and benches that I refinished, sanding and applying a semi transparent stain. I read your really helpful article on putting sealer’s over stained wood, so I won’t be doing that. But is there anything else that can be applied to keep the waterproof protection? Ting or teak oil maybe?

Amy Joseph
Amy Joseph
1 year ago

Hi Scott, my 13 year old deck is in rough shape. Earlier this year I cleaned it thoroughly, repaired rotted areas and then applied Behr’s deck paint. It looks good but I noticed that water is not beading up on the deck. I’ve read your article and scrolled through these questions so it would appear that sealers are not an option. Any recommendations? Thank you.

Sharon
Sharon
1 year ago

Hi Scott can I put a finish like poly, over semi transparent stain on a dresser?

Boyd
Boyd
1 year ago

Scott, thank you for your sharing your expertise. I am building a new deck. I like a glossy/satin look showing the depth of the natural wood grain and color. I am overwhelmed by how much information there is on the subject. What product and process would you personally use if this was your main objective?

Goran
Goran
1 year ago

I have installed composite deck 5 yrs ago.It changed color lit a bit,can I use wood stain
to refresh it

Goran
Goran
1 year ago

Hi I painted my inside stairs with solid pain no stean last night. Now I want to ask you I need use polyurethane after solid pain? I checked stairs they are dried but no 100 % may 70% it still steacky .If I need how long I need to wait to applay polyurethane
Thank you .

penny l gilbert
penny l gilbert
1 year ago

My Tompson wood sealer turned white when I tested it on a part of my deck,could you please tell my why and what I can do to fix it?

Michael D
Michael D
1 year ago

Can you apply a clear coat over a semi transparent wood deck oil based sealer?

Tony Grocki
Tony Grocki
1 year ago

Hi there – I have one board on my deck that gets more rain than any other, it gets worn down every winter, and I recently re-stained it. I thought some sort of extra thick poly on that ONE BOARD would be helpful. I guess I could put 5 coats of stain on it. Any ideas?

Tony Grocki
Tony Grocki
1 year ago

Thanks Scott! I’m going to try a gutter solution on my overhang that pours all the water on the deck, stopping the problem before it gets to that board. Your input has stopped me from trying 2 bad options – much appreciated! Thank You!

Silvio
Silvio
1 year ago

Hi,
We have removed 5 layers of old pain and sanded the front porch. We stained it in red mahogany and it looks very nice. The porch is covered and not exposed to much sun during the day, but it gets wet during the rainy days. Would you be kind to recommend the clear protective coat we could use. Thank you!

Silvio
Silvio
1 year ago

Thanks!

Terri
Terri
1 year ago

Hi Paul, I have an IPA deck and walkway. 8 years ago it was completely sanded on both sides and flipped. Duckback Superdeck Waterborne IPA formula was applied… then a few years later, again Deckback Superdeck Waterborne IPA formula was applied after light sanding… a couple months ago very light sanding and then Armstrong Clark Hardwood Oil based formula was applied. Already the oil based formula is spotting and losing all of its color. Do you have any suggestions of what I can do and what product to use? Thank you!

Pergola owner
Pergola owner
1 year ago

Hello, I purchased a Cedar Pergola kit from Backyard discovery through Lowes Hardware. The unit came with a waterborne “translucent stain for color only”. They also say as part of the warranty that I need to apply some sort of protection. Can you recommend something? I was thinking a clear sealer but there are a lot of posts and blogs that recommend that you should not do this over a stain. I really don’t know how to solve this.

Pergola owner
Pergola owner
1 year ago

Thank you for reply Scott. You’ve reconfirmed what I’ve been learning. This makes me wonder why Backyard Discovery Would sell a pre stained product and then tell you that you need to put protection on it as part of the warranty. I will certainly be asking them.

Richard McGlothlin
Richard McGlothlin
1 year ago

After consulting with staff at a Sherwin Williams, I used Superdeck Exterior Deck Stain Waterborne on an interior stairway application. Given it will not be exposed to the elements, can I safely use a water base polyurethane to create a semi-gloss protective surface. If that is possible how long of a cure does the Superdeck need before Polyurethane is applied. Yes, I do a lot of non traditional and sometimes stupid things.

Richard McGlothlin
Richard McGlothlin
1 year ago

I read your other responses first and understand that poly can’t be used on outside wood. As I noted in my question, the area I used the stain on is an internal staircase that is not exposed to the elements, only human feet and cat paws. I was more concerned about any chemical issue caused by adding a poly top coat, having had an issue some 30 years ago in a theatrical application where an oil top coat was used over a water based paint.

Richard McGlothlin
Richard McGlothlin
1 year ago

Running a test patch today, will let you know. The stain did a great job making some very old and marred treads, buried under carpet for 40+ years look great.

Richard McGlothlin
Richard McGlothlin
1 year ago

For the record, test patch went fine. First coat looks great, three more to go for this non traditional use of Superdeck Exterior Deck Stain Waterborne for interior use.

Jim League
Jim League
1 year ago

Are you supercell 30 on my fresh concrete, in a process of building it’s got dirty and scratched up would like to change the color any advice thank you

Carl
Carl
1 year ago

Hi. I just put down Sherwin Williams Super Deck Exterior Stain, Waterborne Formula, in Flat Finish on my deck (in the color Iron Ore). Can I apply spar urethane over the Super Deck Exterior Stain, or is it unnecessary and/or harmful to the Super Deck Exterior Stain? Thank you.

Michael Tapscott
Michael Tapscott
1 year ago

Hello I just purchased a cedar pergulas,
It is stained but not sealed, I would like to polyurethane it so I don’t have to use a sealer every other year.
What are your thoughts

Ronnie pettit
Ronnie pettit
1 year ago

If I apply this over my painted deck will protect it from foot prints and shoe prints

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