Can You Apply a Clear Sealer or Polyurethane over a Deck Stain? 4.9/5 (462)

This post was updated on March 1, 2022

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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penny l gilbert
penny l gilbert
1 month 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 month ago

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

Tony Grocki
Tony Grocki
1 month 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 month 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
2 months 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
2 months ago

Thanks!

Terri
Terri
2 months 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
2 months 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
2 months 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
2 months 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
2 months 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
2 months 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
2 months 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
3 months 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
4 months 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
4 months 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
5 months ago

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

cliff heatherly
cliff heatherly
5 months ago

Can you apply 100 % acryic deck stain over spar varnish ?

Ian B
Ian B
5 months ago

Hi Scott – question about our deck – I wash and restain about every other year. My problem is that I forgot what product I used the last time around!!! We live at 9000’ in Colorado so the sun really does a number on the wood. Under our porches I thought it had just not been sun damaged as much as the fully exposed areas so I applied what I thought was the right product but I am pretty sure it is the wrong one. I think I have Behr Waterproofing Wood Finish and I went over it with Woodguard exterior wood preservative (oil based) which is for our logs.
Can I just let this all sit and hopefully dry and then wash/strip next season or will the oil just never absorb and I have to address now?
Thanks so much in advance !!
Ian

Stephen Butterworth
Stephen Butterworth
5 months ago

Hi,
Thinking of using a decking paint instead of decking oil. After reading reviews on decking paint, quite a few have mentioned 12 months after applying, peeling as appeared. So my question is can I use a clear sealer on the decking paint to prolonged it’s life…

Stephen Butterworth
Stephen Butterworth
5 months ago

Okay thanks for your quick response.

Dan
Dan
5 months ago

Hello,
We had a new redwood deck installed 4 years ago and stained it with PPG ProLuxe SRD RE wood finish. The stain has held up well, but dirt and grime has built up on the surface. I intend to reapply the same stain this year. My question is should I strip the old stain and brighten the wood before re-staining, or can I simply clean and then reapply the stain?

Dan
Dan
5 months ago

The photos are typical of the condition of the deck. Thanks for taking a look.

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Dan
Dan
5 months ago

Thanks Scott. I recently discovered your website and have marked it as my go to for information on deck/siding maintenance.

Madeleine
Madeleine
5 months ago

Hello
i am using Behr waterproof opaque stain & sealer on an INDOOR new pi e wood floor.
the staining has led to the wood grain expanding so the surface is now quite rough.
Because i think this will make it hard to keep clean, I want to apply some sort of final clear coating. I was going to use pony but then read your posts!!
Do you have any other ideas?
Thanks!

Jackie
Jackie
6 months ago

This is not a deck question but… I am making a table top for an outdoor patio table. I am purchasing a high end piece of “plywood”. Having it cut to size. I’m going to sand it down, place Varathon interior wood stain, Weathered gray then I would like to seal it with a marine varnish. Will this work?

Jackie
Jackie
6 months ago

It will be somewhat protected from the elements. What do you recommend I do instead?

Bud.
Bud.
6 months ago

Good morning, I applied the newer Behr advanced deck over smooth to my additions plywood floor and it looks great, my question is because there is still some roughness to the finish not because of the plywood it has a tendency to scuff which isn’t permanent but unsightly and a housekeeping issue. My question is can you apply floor wax over it as I don’t want to spend the time or money using a poly.if that was the case I could have painted it for less money.

Bud.
Bud.
6 months ago

Thanks, guess will have to wear socks.

Kate Kimmich
Kate Kimmich
6 months ago

We applied Valspar One-coat exterior sealer Clear on our new deck. We were told to use a sprayer for application. The finish turned out horribly. It has bubbles and the finish still feels “sticky”. Now we have one half of our wonderful deck with this mess. The other half has been untouched with the product.
How do we remove this sealer and start over?

Kate Kimmich
Kate Kimmich
6 months ago

Thank you for your help.

Alan
Alan
6 months ago

We asked a company to stain our swing set. They power washed then applied stain. They used Varathane interior stain (English Chestnut). It rained two hours later after the wind blew pollen onto the still wet stain. After drying for a few days it still feels sticky. They’re applying more stain today to even out the color. I called Menard’s about sealant and they recommended this and that but then I found this site saying we shouldn’t do that. Help! What should we do to make the best of this disaster? Thanks for any advice.

Sue
Sue
6 months ago

I have a mahogany deck about 7 years old. Every year I clean it with 30 second cleaner then seal with Penofin transparent oil finish. Within a month the wood has darkened each time. I live on the coast with full sun and high winds. The wood has never looked like it did when new. I would like to use the Restore a deck water cleaner and water based semi transparent. Do I have to strip this first? It has been a year since I applied the Penofin.

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Sue
Sue
6 months ago

Thanks for the prompt answer. Why would I want to put a color stain on the deck and not keep natural?

Lynda
Lynda
6 months ago

I’m a confused newbie. I’ve done hours of research for this planter (first photo) that I just purchased.

According to many reviews, if some kind of protection is not applied it will look like photo 3 within a few months. Some reviewers have advise water seal or poly with shine to give it a beautiful shine.

After reading your many responses here, my plan is all shut to hell. I had bought on the advise of L*wes worker, Valspar semi transparent Stain and water seal Sunlit copper to give it a reddish tone.

And I was planning on mixing this with Spar varnish to give the Valspar flat color stain some shine in it. Dirt rolls off better off of smooth shiny surfaces than flat coarse like feeling ones.

But you say that these products don’t mix and will peel. What can I use to achieve my goal?

Below is the wishing well description and photos of reviewers.

Thanks in advance for your help.

——————–
The planter made of solid wood has a heavy texture, durable and firm. The surface of the board is smooth, after many times of shaping and grinding, the texture is clear, and the corrosion resistance is durable for a longer time. The surface undergoes high-temperature carbonization treatment.

Fir wood is more secure
Carbonized at high temperature
Surface protection
Rural retro style
Durable and firm
Material: fir wood
Color: carbonized color

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brenda
brenda
7 months ago

I have a new deck made of pressure treated pine deck boards. its now 5 months old and ready to seal it or waterproof it. I want to protect it but I want a natural look, no color. Even like the graying as it gets weathered. what product do you suggest we use?

Stan E Weed
Stan E Weed
7 months ago

I used Cabot semi-transparent stain and sealer on new wood deck on my trailer. I have let it dry for 48 hours. The instructions say to only use one coat. Would two coats be better, or not?

R. Johnson
R. Johnson
7 months ago

This is not a question regarding a deck, but thought I would post anyway. We are installing a pine tongue and groove ceiling in our newly built outdoor patio. We already applied Behr Premium transparent waterproofing wood finish in cordova brown (mainly used for fencing, decks, etc…. We really like the color but my husband feels we should now finish it with an outdoor polyurethane. Again, this is a ceiling in an outdoor patio and will be completely protected from rain/water/snow. We are wondering if adding polyurethane is necessary to protect the ceiling from moisture? We live in Michigan so summers are humid and winters are cold. Thank you in advance for any helpful information as we have not been able to find any answers on our question.

R. Johnson
R. Johnson
7 months ago

Ok, thank you very much. We will leave it as is and hope for the best!

Alexandra Docherty
Alexandra Docherty
8 months ago

Hi. I used Ronseal Decking Rescue Paint several years ago. Every year parts of it flake off and needs repainting. Can I buy a product to paint over it to protect it? Some kind of heavy duty varnish? Thank yo.

S Van
S Van
8 months ago

My solid deck stain is peeling and due to plants, patio underneath and fish ponds, I can not do a chemical strip. I have been sanding and like the eorn look( kind of like in your photo). Is there anything I could use over the wood and stain. Clear or a very light transparent stain ? Others suggested Spar varnish but…….

Raymond Palomares
Raymond Palomares
8 months ago

Can I use Cabot semi transparent stain and sealer in bedroom?

emmanuel
emmanuel
11 months ago

thank you guys for the reference, am very much interested on this part of the reference| Clear sealers have no pigment and therefore provide zero UV protection. The same goes for polyurethane. i do a lot of painting and staining, and therefore i like researching and learning new things. I bought a clear sealer for my fence, and right on front of the package it says: WATERPROOF, MOLD AND MILDEW RESISTANCE AND UV PROTECTION. am therefore a little curious when the article says clear sealer do not give UV PROTECTION. i will be very grateful if someone can elaborate on that.

Last edited 11 months ago by emmanuel
Betty Jenkins
Betty Jenkins
1 year ago

I applied deck stain to handmade bed. Can I use a paste wax to give it a more finished look

Ben griffy
Ben griffy
1 year ago

We stained our old deck with semi solid deck stain with sealant. Can we apply water sealant on top of it for extra protection?

Ty Jepson
Ty Jepson
1 year ago

My client stained his fir mantle and a fir shelf in his brand new house with Sico proluxe.
What can I put on it to give it a smooth furniture feel?

Tim
Tim
1 year ago

Just stained a tongue and groove ceiling in a covered outdoor patio w a semi transparent deck stain. I’d like to give it a little more sheen w a clear sealer…do I really need to worry about peeling? Obviously with it being a ceiling it won’t see any sun or foot traffic.

David Searls
David Searls
1 year ago

Hello was googling from UK about protection and stains and came across this helpful site.

The old pine window of the pine conservatory was rotten. The whole of the conservatory looks to have been stained with a dark teak when all new. I have made two replacement windows using recycled pine, to fit in the old windows slot (two because a new boiler flew meant original window did not open). The new replacement pine is a mixture of old/new salvaged pine and untreated pine. First time have made windows or anything (apart from decking) to be exposed to the elements. And did not think of issues relating to stains/preservatives/coatings etc. Just thought I could apply deep preservative and then tint or other way round. 

Apart from slight difference in color between the pressure treated and untreated pine parts, the New windows seem nice and solid, would like them to stay that way and also blend in as much as possible with existing dark wood. Does not have to be perfect match-up as old conservatory is a bit higgledy piggledy in any case.

Somehow have ended up with a mixture of stains and oils. I also have some clear Decking Preserver, which I previously used on some decking some time ago and it seems to be good
stuff.

I tested the teak stains “Ruskin’s Interior & Exterior Wood Dye – Penetrating stain for all new or stripped wood” on some off-cuts and two coats seems to give a near enough match-up. The stain says it can be diluted with white spirit so I guess it must be an oil based stain.

The instructions on the Decking Preserver indicate that it cannot be over-coated. And that it should not be used on timber that has been treated with a preserver.

Main concern is with giving new windows as much protection against the elements and rot as possible. i.e. the preserver I already have. But if I apply the oil based
stain first to get the color I want, will this prevent the preserver from fully working?

Hate waste and like to use things at hand, but maybe this is not possible this time after reading some of the comments here.

Before I buy and hope for good match-up, is my only option to try and get some preservative with the same color as the existing conservatory.

Thanks for any help.

David Searls
David Searls
1 year ago
Reply to  David Searls

Thanks for reply. So does the stain also act as a preserver? Mainly concerned about the new bits of timber which were not pressure treated when I got them.

David Searls
David Searls
1 year ago
Reply to  David Searls

Sorry, I suppose the answer is in the fact that the stain is for “exterior” use. I guess that
implies protection.

Thanks again.

Lucio DaMotta-Santos
Lucio DaMotta-Santos
1 year ago

Hi, I stained my house and I used the stain to do my breezeway deck can I apply a sealant to protect it?

Dale Patterson
Dale Patterson
1 year ago

I power washed my deck and most of the stain came off I want to know if I can seal it or re stain it

Brenda
Brenda
1 year ago

My small deck is 3 years old, never had anything put on it. After powerwashing it, I really like the colors that popped out. Blendings of gold, red, and green. They faded as it dried. Anything I can put on it to bring out those colors and then a recommendation for a sealer to protect it?
?

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Diane H Dockeney
Diane H Dockeney
1 year ago

We did a solid dark gray stain on a new deck. Love the color but it looks dirty and you can see every footprint. I have spent lots of time cleaning with deck wash and water but this seems never ending. Anything you can suggest for a easy cleanup?

Dale G
Dale G
1 year ago

I have a deck at a remote location by the Atlantic Ocean. One of them was stained with solid water based stain years ago.

I was wondering if I no longer want to keep putting solid stain on it, 50% pealed now can I put Thompson’s water sealer over it for this year to help protect it from water this year?
We come here every year for 3 weeks and running out of time to try to strip it all off, not to mention it is 12 feet off the ground so striping will be a big job.
I don’t care how it looks but if applying water sealer helps that’s all I can do right now. I power washed off what I could already.

Thank you in advance for your support.

Dale G

Charles vinson
Charles vinson
1 year ago

What can be used on deck to give wet look it has been stained couple years ago or longer not sure it has a Thompsons water seal on it but customer wants a wet look what to use What to use any ideas hum?

Maya Thomas
Maya Thomas
1 year ago

I am leading a team to build benches with 150 year old oak barn wood for my Eagle Scout project.The wood isn’t stained but is a beautiful dark color when wet. From what I have read, I think I can use a clear, oil-based, polyurethane. Is that correct? The benches will be outside.

Maya Thomas
Maya Thomas
1 year ago

What would you recommend for a protectant then? I do not want to stain it, I only want to protect it from the elements.

Rae
Rae
1 year ago

Can I add a dark regular stain to a deck sealer? If the sealer is water based I could use a water based stain.

J. Vaughn
J. Vaughn
1 year ago

I live in an apartment where I’ve taken up the old carpeting and stripped the glued padding. Now I found they actually used deck wood in this room (don’t ask me why). I’m going to sand it and clean it but would like to paint it and put polyurethane over the paint. Can you think of a better way to deal with an indoor deck floor?

J. Vaughn
J. Vaughn
1 year ago

Are you sure about that?

There are hoards of videos on YouTube showing you how to poly over paint.

Joseph Zalatan
Joseph Zalatan
1 year ago

I just purchased a wooden swing set for outdoors is it OK to stain and then put polyurethane on it what do you suggest

Debra Rizzo
Debra Rizzo
1 year ago

I Had My Deck Rebuilt, With Brand New Decking, And Railings, Let It Cure For A Year With Nothing On It, Then Used Lowes Valspar Semi-Transparent One-Coat Exterior Stain & Sealer, 1 Year Goes By, The Following Summer, I Am Hosing It Off My Just A Garden Hose, No Pressure, And The Stain Literally Peels Right Off, So I Sand, With A Palm Sander The Top Rail & Floor As Much As Possible, Hose The Saw Dust Off, Now Am Using Olympic Elite Solid Stain & Sealer, Should I Put Down Two Coats On The Floor?? Also, Do I Need To Seal This On Top To Keep It Beautiful!! The 1st Photo Valsar, 2nd Photo Peeled, 3rd Photo Olympic Elite!

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Dave
Dave
1 year ago

Hi I live in Ontario Canada and I have a problem with my deck.
I completely sanded the deck last year and applied a Home Hardware stain that has a plant oil base.
The stain went on well however the this spring where ever there was a knot or imperfection in the boards the stain came off.
I do not want to sand the deck again so looking for a product to cover the knots and imperfections and apply the same stain or a product that I can apply over the complete deck.
See file for picture.
Thanks,
Dave

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Gerry
Gerry
1 year ago

I have a 5 year old deck. I stained it a dark brown. Everyone around me has bird feeders. The birds sit on my deck and poop!!!!! YUK. I have a hard time cleaning it off the deck and railing. I want to put a clear coat on the deck to make cleaning it easier. what can I use????

Matt
Matt
1 year ago

Applied restore a deck stripper and brightener. Am I ok to apply stain after 48hours of drying? Is this the way it’s suppose to look?

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Matt
Matt
1 year ago

Thanks! Suppose to get rain every other day for the week is it ok to wait to stain?

Matt
Matt
1 year ago

I stained deck 2 coats wet on wet of twp100 it rained about 36hr after do I need to put another coat on it or do I just leave it? Or is there anything I have to do before adding another coat?

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Matt
Matt
1 year ago

Thanks for all you help. I’m happy with all the products you recommended and how it turned out

CJO
CJO
1 year ago

We have a deck constructed with Trex or similar, but the railings and posts are an exotic wood (IPE?) and the finish has faded over about 6 years. Not sure what was on them previously. Recommendations to refinish the railings-stain vs. urethane vs something else?