Update 2019 for Apply Polyurethane to A Deck?
Welcome to DeckStainHelp.com, the internet’s number one reference for all things wood deck restoration related. As before, we do not recommend the use of polyurethane stains on outdoor decks. We always appreciate your comments and questions, so feel free to leave one below.
Should I Apply Polyurethane to a Deck?
Selecting a deck stain or sealer is a vital step when finishing your deck or when your deck is in need of being recoated. Wood decks are exposed to severe weather conditions and need to be protected with the correct type of wood sealant.
The best choice for finishing a wood deck is to use an exterior wood stain. A semi-transparent penetrating stain will provide adequate water and sun protection. This type of deck stain will enhance the natural beauty of the wood increasing its appearance.
When refinishing a deck, do not use a varathane, varnish, or polyurethane coating that films on top of the wood, creating a “shiny” finish. These types of finishes are mainly used for indoor applications and break down easily when exposed to the elements. Rain and harsh UV rays will cause polyurethane to fail quickly, which will subject the wood to weathering. The polyurethane will blister and peel on exterior wood. This will create a nightmare to fix where heavy sanding will be involved in the removal. If you want a clear or natural look to your deck, consider a deep penetrating (non-filming) clear deck sealer or better yet a semi-transparent deck stain in a natural tone.
When looking for the right deck stain you will find a large variety of colors. Finding a color like Natural, Cedar, or Redwood in a semi-transparent stain will not hide the wood grain as a solid stain or paint would. This can give your deck the natural look you desire while still giving the wood moisture and UV protection.
Do some research on your deck’s type of wood. Search for colors that will give you the final results you want. Do not apply polyurethane to a deck or it may jeopardize the deck’s beauty and longevity. The outdoor elements are too harsh for polyurethane making it a bad choice for exterior deck use. Keep your deck maintained with the proper choice of deck stain and it will be there for you to enjoy for many years ahead.
Please Ask Any Questions Below
Wood polyurethane work on pressure-treated wood that’s been dried at least two years. These decks are totally covered from the sun. Your help would be appreciated
No, it will not work on a deck.
I have a ~ 10′ x 10′ “interior” redwood deck in an atrium that is covered by correlated vinyl roofing material (such as for a greenhouse). It is adjacent to my kitchen. It is edged by 2 interior walls and two exterior walls. (Put in by previous owner w/o any means of ventilation other than when the slider to the outside or the other slider to the kitchen are open.) I made the severe mistake of putting a water-based polyurethane coat over oil-based polyurethane, wanting to create a more glossy surface and look. Quite frankly, the oil-based PU seemed to hold up well without any peeling. etc. BUT, the water-based PU bubbled/lifted up in several places. Now I’m working hard to strip all this away. My plan was to then reapply a PU. But since you recommend against that for outdoor decking, and since this does get wet from condensation now that I have great sealing sliding glass door in one of its surrounding walls, maybe I shouldn’t? I’d appreciate your input. Thanks.
To fix you should power sand it like you would for a hardwood floor. Make sure to sand all the current coatings off. Stain with a penetrating wood stain like the Restore A Deck Wood Stain or TWP 1500 Series.
I have 3 sets of treated wood steps in middle Georgia that I have pressure with Clorox and jomax. I need a good clear sealer that will last for these. What do you recommend?
Also I have a wrap around covered porch that I did the same cleaning to but don’t plan to seal since covered. Your thoughts?
A clear sealer will not provide UV protection from graying. Must be tinted. Do you want the wood to gray naturally?
Ask a Question or Post a Review…On second thought the cabin is stain in the brown color. So maybe could stain with a lighter brown. What would you recommend? Would the stain need to be sealed?
Anything on covered porch?
Try Natural Oak by Armstrong Clark. No need to seal over a deck stain.
I have white oak in my kitchen, with a Minwax provincial stain, a satin polyurethane. I’m going to stain my deck. What would be the best possible match for my deck.?? Any suggestions would greatly be appreciated.
It is not possible to whitewash a deck nor can you apply a poly to outside wood.
So are you saying there isnt a poly product on the market that can be used successfully in an exterior application?
Correct, they will all peel on a deck.
I know you’re only decks but can you recommend something for a wood floor on a covered porch that will protect from water, uv and prevent (as best as possible marring or scratching the wood surface from furniture?
You need a penetrating stain like one of these: https://www.deckstainhelp.com/the-5-best-deck-stain-reviews-and-ratings/
Hey there. So my contractor just built a beautiful deck, but then one of his crew applied a coat of interior poly on top of it. I told him he needs to remove it so we can put something more appropriate on (a transparent stain likely), but he’s pushing back, saying we can apply something on top of it. Like an outdoor clear sealer. I’m arguing that it won’t work, as the outdoor sealer won’t stick to the poly, and the poly will just crack and blister pretty quickly.
Can you please chime in so I have some back up? What would you do? Chemically remove the poly, and then let it sit until spring, and then stain? (It was build a few weeks ago). I live in Vermont, so it will get some serious weather this winter.
Thanks!
He is wrong. Nothing will go on top. The only way to remove is to power sand this off. Deck stain strippers will not get it off. Then let it sit to spring before proper prep and stain.
I have a mahogany deck that has had one coat of Sherwin Williams deck sealer. Realizing I want it to look more like the wood has “popped” instead of the dull grey. Any suggestions on refinishing and getting more of a wet look?
You will have to remove the SW Sealer first. Once stripped and or sanded off, brighten the wood. Then stain with Amber by Armstrong Clark or TWP in Honeytone.
I just used a deck sealing stain, Super Deck transparent stain (cedar) on the pressure treated deck I just built in Southern California that allows the grains to show thru and seems to be what is the recommended procedure, but I’m worried about splinters on my 3 year old’s hands. If varnishes like poly and marine varnish are no good for outdoor decks, how then to avoid the kids getting splinters? By sanding? I don’t know about pressure treated wood on the west coast, but splinters from pressure treated wood back east can burn. Thanks in advance!
You cannot top coati it so not much you can do to prevent splinters.
Hi, I am seeking for a good finish product for an exterior teak deck we are going to install in Guanacaste, Costa Rica. Our inital plan was to use a urethane varnish from Pinturas Sur (Speed Dry Satin Varnish is a single component, solvent base varnish, formulated from urethane resins.
Thanks to its features, it protects surfaces exposed to environmental conditions such as sun, rain and
humidity. Quick drying, it provides a transparent satin finish, smooth and long lasting. It protects and
highlights the natural beauty of wood.)
Also, some other guys are recommending Carver Protect Deck, which is a water based penetrating finish).
What are your thought on this?
You cannot use a urethane on deck, it will blister and peel. Never heard of Carver.
Your review of the Flood Pro stain for decks has Urethane which you state stops cracking. YET HERE you say dont use Urethane.
Wow
Polyurethane and a urethane modified solid stain is not the same thing.
I just stained my front porch with cabot premium wood care, The Ultimate finish (Moonlight Mahogany) I absolutely love the way it Looks! After reading all the reviews and your recommendations I’m very nervous that it won’t stand the test of Time! I plain on using a water based stain on my back cedar deck. My question is can i go over the Cabot stain on my porch with the water based stain to hopefully give it some extra stay Power?
No, you cannot do this.
I’m actually building a backyard climbing wall. We want all the water/UV/weather protection we can get out of these deck stains but also want there to be a slick texture or film over the wood so that it is not just a wood texture. This is what brought me to this article because we like the texture that 3-5 coats of polyurethane gives you.
We live in Southern California about 30min from the coast. The walls will are under shade at least 50% of the day, and will also have a UV screen in front of it when not being used.
Any ideas on how we can accomplish?
It will peel. No way to accomplish what you want to do without dealing with constant maintenance to maintain the peeling and mildew that you will get.
We built a porch with ezy breeze windows room over new deck, treated pine wood flooring. We want to use an oil stain on the floor and protect it with a satin coating. What is the protective finish we should use, or oil based stain enough?
Thank you.
See this about new wood: https://www.deckstainhelp.com/staining-a-new-deck/
I live in cold and snow country. My deck is 5 years old and every year, I have to re-stain it. I have used everything.
NOW, I want a solid paint, something that will last. I am tired of the every year upkeep. What can you recommend
that will last. Seeing the wood through the stain is not important anymore. My deck looks horrible right now, and I want a clean and fresh look.
Thank you,
Bobbi
A solid stain will peel in your environment most likely. In addition, prep is key. You will need to remove all the previous coatings for your new coating to work well. Applying a solid stain over previous coatings will not work well.
I want a paint, I have already used a solid stain, the wood is always sanded off. Nothing works
A paint will not work on a horizontal deck. Try this deck resurface product: https://www.deckstainhelp.com/gulf-synthetics-deck-revive-review-2015/
Hi I’m looking to put something on my interior honey house deck, it is raw spruce plywood. It never sees sun or rain, but is walked on and gets wax/honey on it. What would you recommend?
Thanks
I am sorry but we do not have any experience with interior wood like this. Our experience is strictly outside wood and decks.
My contractor put marine varnish on my new redwood deck and now dark discoloring seems to be happening. He said it needs another coat (after some sanding) to provide protection but I’m fearing that he made a big mistake and I might need to sand it off and start over. Help! Thanks.
You will need to sand it all of and start over with a proper deck finish to fix this.
Thanks for the help. I’m learning a lot!
You are welcome!
Would a polyurethane coat be suitable on decking that is partially outside? The laundry room is built on top of the decking and is enclosed on all sides.
No, any exposed wood and the poly will peel.
Hi, we are using black japan decking stain and wondering what we should use to seal it?
Use a stain like the TWP 1500 or the Armstrong Clark.
I’m a boy scout working on my eagle scout rank. For my eagle project I am going to be refinishing a couple of Redwood play structures. In the past, lacquer has been used but it has lasted less than a year before it starts pealing a bunch. Along with hot weather, the play structures are also bombarded with the water from some nearby sprinklers every other day. What would you suggest I use to refinish the structures? I’d like it to last as long as possible. Also what would the preparation and application process include? Thanks!
You would have to power sand all the old lacquer off to fix this. Once fully sanded, you can use a penetrating stain. Try Armstrong Clark.
Thanks! Also, will the penetrating stain keep water from soaking in and prevent splinters?
Yes.
Sweet, thank you! Also, I checked on the Armstrong Clarke website and according to it the semi-transparent stain will last about 2.5 years. What condition are they saying that the stain will be in after that time. Also, what is the reapplication procedure for when it comes time to reapply the stain? Thank you for your time!
Just clean and recoat when needed.
what is the best clear product that stands up to salt for open porch flooring?
Try Defy Extreme Clear or TWP 1500 Clear.
I find the stain I put on my deck does not adhere and any movement of furniture etc. goes through the stain exposing the pre stained deck. Is this the fault of the stain or my application?
Depends on the brand of stain, how you prep, and or how you applied. It could be many different reasons while it is failing.
Hello:
I’m building a beach bar that previously had 2×6 flooring with a 1/8-1/4 inch space. I’m now going to use 1×6 tongue and grove on the bottom and second floor. I’d like to use a wood sealant that won’t wear very fast with heavy traffic with sandy feet and will help create a waterproof barrier between floors. What is my best option? Olympic Maxium? Polyurethane? Behr Deckover? Stain and water seal?
Thanks in Advance.
AE
None of those. As the article states you cannot use a poly on the exterior decking. Behr Deckover has horrible reviews. You cannot stain a floor and then seal on top and Olympic is average at best. New wood also cannot be stained or sealed right away: https://www.deckstainhelp.com/staining-a-new-deck/
With your heavy traffic, there is not a good solution for you that would last more than a year. You could use a semi-transparent filming stain like the Sikkens Cetol DEK, but you will be constantly maintaining it.
I’m looking to protect wooden beehives from the elements, but I don’t want to use paint. I’d like to keep the natural beauty of the wood.
Would a clear deck sealer be best or an exterior-grade polyurethane? I’ve already stained the boxes so the product would go over a stained surface.
Hi Jarad, you cannot seal or coat over a exterior surface that has been “stained” already. Polys will peel as the article states.
Hi : We have a redwood deck covered the railings are exposed to sunlight and peel ? It has been coated with a urethane in the past the deck does not peel but needs a re-coat Don’t want to use an oil based product ??? What are my options
Sanding it all off and start over with a proper penetrating stain like one of these: https://www.deckstainhelp.com/the-5-best-deck-stain-reviews-and-ratings/
Wondering what would be the best polyurethane for a screened in Gazebo pressure treated floor?
As the article states, never use a polyurethane for exterior wood.
Thank’s for that info
Is oil base stain better than water base? Does it last longer?
Varies a lot on the brand and type of stain. See this for tips: https://www.deckstainhelp.com/water-based-vs-oil-based-deck-stains-2017/
What can I put on top of Behr’s paint/stain to prolong life in uncovered portion of porch? Thinking some type of polyurethane.
You cannot apply anything on top of a deck stain to prolong the life. It will peel.
my deck is painted, leaves are falling and staining the deck. is there anything that i can go over the paint that will stop this? maybe polyurethane?
Sorry but no.
I had just finished powerwashing, sanding, and applied semi-transparent waterproof stain. Now thats its all done; Ive come across think about what to do with the cracks and small splits in the wood. I was thinking about polyurethane it. Now I’ve learn its not a good idea, any suggestion as to filling in the small cracks and splits to having a smoother surface?
The filler will not work on exterior wood and semi-transparent stains. It will not blend. Just leave as is. It is normal to have cracks with exterior wood.
i am using superdeck semi transparent heart redwood stain on my 1 year old never touched pressure treated deck as i have seen nightmares about using Behrs.
We have a very large deck, about 50’x10′ with railing. Last summer we cleaned the deck and added a water protectant. As the sealer dried we noticed several white spots, these continued to increase as time went on. I sanded off the white spots and tried to re-stain them. This is when I noticed the stain the former owner used had polyurethane in it. We have sanded the entire deck but I want to be sure I avoid having any further issues. I’m assuming I should pressure wash the deck again just to be sure it’s clean before I stain it. Is there anything else I should do?
Thanks!
Use a wood brightener as well.
My deck was painted by the previous owner with a solid stain that is now peeling and flaking. I am thinking I need to sand it all off and cover with semi-transparent stain as has been suggested. However, the nails used on the deck are not stainless steel and they rust if exposed to the air. Will the semi-transparent stain sufficiently cover the nails so the will not rust? I am worried that it will not, and I will have a deck dotted with hundreds of rusting nail heads.
No, the new coating will not seal the nails and stop the rust.
So is there any alternative to sanding and recoating with solid stain?
Replace the wood is always on option, but expensive.
I have a cedar deck that gets tons of sunlight. I tried all kinds of deck stains and even teak oil. The best product I found was something called a Super Deck.
that is what i am using,,superdeck heart redwood semi transparent stain
I rented deck sander at the hardware store. Used 80 grit followed by 120. I use an oil base stain that has to be reapplied about every three years because of a south exposure…nothing will last forever on a deck, if you want to "poly" it, I would use a high quality spar varnish used on boats, but again, you will have to sand it back down and re apply at some point.
This was great information. I did what you said not to do and the results were exactly what you said would happen. Peeling and blister and now it's to the point the paint I used completely peeled and blistered away from the wood. Now I can just see the bare wood. This was a costly mistake since polyurethane is expensive.
I have used an Exterior Solid Stain on a Pine Floor INSIDE. I'd like to put a top coat of some kind on it. Since this is not exposed to the elements, would a polyurethae coat work?
You cannot apply anything on top nor would it help. It would make it blister and peel.
Is there any kind of a deck coat/sealant that prolongs the life of the coating, or wood? We are considering redoing our deck with the Poly resin material/poly wood that lasts for life. But I thought I had heard somewhere that there is now some type of a deck coat/sealant that is somewhat similar to the long life of the poly material, so there is not a need to recoat as frequently. Please let me know; maybe I am way off base! Thank you.
No such thing.
Hi , We installed a post and beam covered porch about 10 years ago using western red cedar beams and rails. We were told to just use a varathane clear oil based Exterior finish to seal and protect the wood. It looked fantastic at the time, but the last couple of years, it started to look like your picture in the article above. We tried for nearly a week to sand the wood back to pre-seal, and it just wouldn't come off. So I went to the paint store and they sold me a Benjamin Moore Exterior Stain Remove, which I tried on a portion of the post and beam/railings. It turned the wood dark in the places where there was no stain left, and bubbled up some of the remaining stain. It was a mess. We let it dry and tried to sand it again, but it just will not come back to the same colour. So we thought that perhaps if we used the same product to just go over the wood, it would blend in and look ok….it is still wet, but it looks like it isn't going to work. I am afraid that our only option is going to be to paint the post and beam, which I really don't want to do as it is beautiful Red Cedar. Can you help with some advise?
You have to remove and the only effective way of doing this is to continue to sand. Try a belt sander. You might want to hire someone as well. After the sanding, you may need to apply a wood brightener. This will lighten the wood and also remove the dark spots that the stripper left. After all this is done, use a lightly pigmented penetrating stain like TWP or Armstrong Clark.
Is there any outside deck stain that looks shiny or wet
Not really as they will peel if shiny. Bad idea.
We recently had our wood deck stained and sealed. The company we hired said their seal is mixed in with the stain and is applied in one process. I'm just curious if that sounds right? Also, now that they are finished with our deck, should water continue to soak right into the wood when it rains or should there be more of a beading of the water on top of the deck?
Beading is not important. It should \”shed\” the water. Sealers and stains are mixed.
I put a clear coat of stain to my cedar deck and it left a yellow look where the stain overlapped. How do I get rid of the yellow look.
Strip it all off and start over.
You mention several times Do Not use poly but you never mention what you should use. Would you recommend an oil base product such as; Sherwin Williams semi transparent cedar deck stain.
This whole site is all about what we suggest and in general that is a penetrating semi-transparent stain that does not peel. Please see ratings on our site.
I recently installed new T&G pine on a covered porch and used a chocolate covered weatherproof transparent deck stain
My wife is wanting to put a coat of polyurethane over the stain; not so much for the gloss finish, but rather to protect the wood itself from additional stains (melted popsicles, spilled wine, etc.) Im not convinced this is the best approach, as it may cause the porch to be slippery when wet. I also thought that the stain itself would provide a decent barrier so long as I continue to take care of it each season.
Thoughts on applying this finish over the stain?
You cannot add a coating of any kind over top of a deck stain. It will not work.
Hi there. I have applied a dark varnish to my wooden deck, but it hasn't come out as dark as I wanted it. Is there any stain / tint I can apply over the varnish to make it darker?
No that is not possible. Sorry…
Is there a difference between urethane and polyurethane? This can (solid color composite deck stain) only refers to urethane, but the clerk called it polyurethane. She also claimed it could be used for conventional wood decks and could be painted over with latex paint. This product was applied to a wood deck previously painted with latex. INGREDIENTS: Nepheline Syenite, Long Oil Alkyd Resin, Exempt Mineral Spirits, Long Oil Alkyd, Mineral spirits, Urethane Alkyd resin, Xylene, Proprietary Solvent and Ethylbenzene. This product was discontinued due to "harmful formulation" and deep discounted. I was told it can be thinned with standard paint thinner, and if a coarse surface was desired sand can be added. I expect it to exhibit better longevity than latex coating, which would peel in areas after a year or two.
What brand and type is this product?
I want a wet look or shiny finish to our cedar deck. How can I archive this that will hold up. Obviously poly sounds like a no go..any other sealer to put ontop of the stain or something I can use. We are staining it a dark brown and its a brand new cedar deck. Thanks.
You cannot achieve this without major problems down the road. It is just going to create issues.
i live in a rainy climate and the stain wears off on the horizontal parts of the deck. i'm sanding and restaining today, but wondering if i need to sand it first, is that necessary do you know? i'm using a tinted stain
You have to prep before reapplying. Sanding is not always the best prep. A good deck cleaner and wood brightener works better.
Does an older deck need some sort of preparation before staining?
Cleaned and brightened for the prep.