This post was updated on April 4, 2025
Mill Glaze on Wood Decks
DeckStainHelp.com has become the Internet’s go-to site for professional wood deck staining tips. We often hear about mill glaze on new wood surfaces. We offer tips on how to remove pesky mill glaze and prep new wood for an ideal surface. We encourage discussion on our site, so feel free to leave a comment below.
What is Mill Glaze on Decking and How to Remove?
When using new wood to repair or construct a deck it is important to know that the wood will not stay new for long. When wood is exposed to sun and rain it quickly turns gray and begins to soften. The wood will have to be protected with a deck stain as soon as it seasons for a few months and dries out.
Before staining a wood deck it should be cleaned. There is some debate as to whether or not new decking needs to be cleaned prior to staining. After all, it may still look new and not be very dirty. The truth is, new decking does need to be cleaned before it can be stained or sealed.
The reason new decking should be cleaned is mainly to remove any mill glaze from the wood. Mill glaze is the glossy like film that develops on milled lumber during the production process. When lumber is being cut, the high speed generated from the lumber planers creates high temperatures. These hot temperatures cause the wood sugars to form a glaze on the surface. This mill glaze is present on most types of newly milled wood like pressure-treated pine and cedar.
If the wood is not cleaned to remove mill glaze, it prevents any deck stain or sealer from properly penetrating the wood. This can result in peeling, flaking, poor performance, and premature failure of the stain.
To remove mill glaze from decking, clean the wood with a wood deck cleaner and a light pressure washing or heavy scrubbing. After cleaning, apply a wood brightener to help open the wood pores to accept stain.
If necessary, once the wood dries it can be sanded to remove any remaining mill glaze and to further soften the wood to get better stain penetration. Once mill glaze is cleaned from the wood and it dries, apply a quality deck stain to protect the wood from weather damage.
Ask Any Questions Below!
Can you sand new hardwood decking to remove mill glaze.and what’s the best decking oil for balua decking
Hi Paul,
Sanding is not the best way to prep new wood and will not allow the stain to soak in fully. See this about new wood: https://www.deckstainhelp.com/how-long-should-you-wait-to-stain-a-new-deck/
As for the stain, look at Armstrong Clark in a hardwood color:
https://www.deckstainhelp.com/ipe-exotic-hardwood-stain-review/
A semi transparent stain was applied to a 3 month old pressure treated deck, but a lot of green color is showing thru the stain. Why is this
That is part of the wood’s pressure-treated process. Nothng can be done about it.
After staining deck is blotchy, with uneven color. New cedar, waited a year, then cleaned, power washed, and brightened. We used all Restor A Deck products. Do we need to sand it?
Post some pictures.
I read somewhere that you can also do a lite sanding to prepare new decking for stain. I have a Penofin wood cleaner I am testing with, and I also am sanding. I prefer the sanding believe it or not because of the water mess. Anyone have any comments in this regard? I suppose I will go back to washing to be safe.
Sanding will not prep new wood for staining properly. You need to weather the wood for 4+ months and then clean and brighten for prep.
Hello,
I have a little bit of an issue. I installed new pressure-treated deck boards in March of 2020 and I let it weather properly. March of this year I planned on prepping and staining but unfortunately got busy. So, last week I finally had the opportunity to start. After reading several online posts, I sanded with an orbital sander and 80 grit paper to remove the weathering and mill glaze. Well, I quickly realized that it was going to be a very long process so, I decided to just lightly sand to remove splinters, and then I would clean. After sanding, I used E-Z Deck cleaner and followed the directions exactly. After one day of drying, I noticed a white residue on most of the boards and the mill glaze was still present. I once again went back to the internet to research this issue and it was either let it wear off, sand with 60 grit, or clean it again. Yesterday, I attempted to sand it with a pole sander and 60 grit paper. I used a pretty good amount of pressure and nothing was coming off, residue or mill glaze. So, should I try to clean it again and use a pressure washer? Or, sand with an orbital sander and 60-80 grit paper? What is your thought on using a stripper to remove the residue and glaze? Thank you for any advice you can provide.
Post some pictures for help.
Not sure if you can see the mill glaze but it’s there.
That is not mill glaze but oxidation fuzzies. Typically does not show when stained.
Hi, I was planning on re-staining a weathered red wood swing set with Armstrong Semi Solid stain. The problem is I am using new pressure treated wood for the main supports, Armstrong says you cant stain new wood for 12 months. Why is that, and is there anyway to cut that time down. We sanded everything (doesnt that help remove the mill glaze) and let the wood dry for a few weeks. I dont mind re-staining in 12 months but I would like to stain now before putting the swing set back together.
The semi solid seemed liquidy enough that it seeped into the new wood on a sample – doesnt looke like it will peal like solid stain, but not sure about drying time
Thanks
No, you cannot speed up the process of staining new wood. It is not about mill glaze it is about porosity.
We have just installed a brand new 1200 sq ft deck of pressure treated wood and we are trying to figure out proper steps before car use a Valspar solid stain on the entire deck. I understand we are going you need to get the mill glaze off first but all the reviews I have read on Valspar and Cabot wood deck cleaner are horrible ! Looks like Olympic use to have a good one but no longer available. We thought maybe we could just lightly sand the entire project but that apparently in not good to do either. Is there a DYI Washington process we could use to get mill glaze off and then just let out deck dry out for several months before we stain? The Valspar water based stains SAY you can apply it to damp wood!
We are reading so many mixed reviews!
Your opinion for brand new pressure treated deck… we definitely want to use a SOLID stain on it because our friends have been pleased with theirs.
Help!!!!
See here about new wood: https://www.deckstainhelp.com/staining-a-new-deck/
Valspar is garbage. See here for reviews of solid stain: https://www.deckstainhelp.com/what-are-the-best-solid-color-deck-stains/
Hi. I am installing a new t&g porch dog fir in Seattle. I didn’t account for mill glaze and had actually never heard of it. Well, now about half the wood has the spots everywhere and that just isn’t going to fly with person I am installing it for. I used Daly’s Deck Stain (which was fairly popular in the PNW) and the rep there told me I didn’t need any conditioner or to do anything for prep since it was new wood. All six sides are already stained and the plan was to get it and stained in one of our last windows before we have rain for the next 6 months. How can I fix this? Thanks for you help.
Strip it all down and then brighten the wood. Install the wood, let it weather naturally, then prep again and stain: https://www.deckstainhelp.com/staining-a-new-deck/
Staining all sides is not needed and causes more harm than good in some cases.
Do you not recommend staining all sides? We are having vertical shiplap siding installed and are planning to stain all sides with Ready Sill. The pine siding was delivered and appears to have mill glaze on on it, which led me to this site. What is your opinion about staining both sides and edges?
No need to stain all sides, just the exposed wood.
See here about new wood: https://www.deckstainhelp.com/how-long-should-you-wait-to-stain-a-new-deck/
Might want to reconsider Ready Seal as well. Read review and comments below: https://www.deckstainhelp.com/ready-seal-wood-and-deck-stain-reviews/
Thank you! What would you recommend for stain for vertical pine siding?
Any of these brands: https://www.deckstainhelp.com/the-5-best-deck-stain-reviews-and-ratings/
I am in LA>..i like Daly’s stuff.
Is weathering and cleaning and brightening to remove mill glaze for stain prep necessary both for new cedar vertical tongue in groove siding as well as cedar planks for decking?
Yes.
Can mill glaze be removed from new cedar siding just by sanding, without using wood cleaner and brightener?
Sanding does not prep new wood very well as it can reduce absorption. Best to weather the wood and then clean and brighten for prep. Easier as well.
DID I RUIN OUR NEW DECK?! Went to prep newly installed deck (4 months ago) for staining. Did water test and drops seemed to absorbed so I thought wood wasn’t treated. Washed/scrubbed with a Bob Villa recommended ‘natural cleaner’ of Oxyclean, some borax, and dish-soap. As I scrubbed, gunky grayish lumps started appearing in my brush and the boards became very slippery. I clearly see some ‘finish’ coming off-now the boards are unevenly free of this ‘stuff’. Should I just keep scrubbing and rinsing to get it all off? Is it, indeed, mill glaze?
It is oxidation coming off. You need to properly use a deck cleaner (Bob Villa does not know much about decks) while pressure washing. Brightener after.
thanks
I have new cedar decking. Installed 5 weeks ago.
i live in Seattle Washington, It had rained on it about 10 days ago, but otherwise dry and tempurture in 80s.
Read various website about how to stain and all talked about mil glaze.
Board are very smooth and I suspect they must have mil glaze on them.
Didn’t even bother to do the water test on the board.
I bought Lowe’s Wood prep that has Oxalic acid (said on label that it removes mil glaze).
I sprayed it on, vigorously prushed the wet treated boards (doing 4 boards at a time) to make sure it really does a good job. let it sit on the wood (keeping it wet by apply a little more solution) for about 10 min, then rinse it off.
Now I’m ready to put the stain this weekend, I pure a little water (about 1 oz.) on one of the deck boards.
Water just just sits on the top of the wood.
It took about 5 min for water to get soaked into the wood.
Is that acceptable?
How long should it take for the water to get soaked in?
I figured if the wood is ready for staining, it would soak in the water within first 10 seconds.
That didn’t happen. It took 5 min.
On various sites that talk about this and all these questions here, no one mentioned how fast should the water get soaked into the wood.
Should I
1. Go ahead and stain the deck (5 min is fast enough)
2. Do another treatment of deck prep, maybe use another product.
3. Sand the deck since wood prep didn’t open up the wood enough.
4. Wait another month to let is weather so me more.
5. All the above
6. (insert your option here)
Thanks,
Norm
See this about new wood and it will answer your questions: https://www.deckstainhelp.com/staining-a-new-deck/
We are building a screened-in porch. Floor is Trex so no staining. The supports are pressure-treated 6×6 pine and the horizontal railings are also pressure-treated pine 2×4. There are darker and lighter areas on the wood which I can’t tell if they are dirt, oxidation, or mill glaze. Sanding leaves stripes of darker surface where the sandpaper didn’t reach (since the surfaces are not completely flat). Question is – how to tell if those areas are dirt or mill glaze or weathering discoloration. Can a person stain over the wood even with the discoloration areas? Is it essential to do the cleaning and brightening prep after allowing time for the wood to “dry” or do I have to sand away the discolored areas? Thank you.
Post a picture.
We had floor and handrail deck boards replaced over 1 year ago. Installers never power washed or sanded to remove mill glaze. The guy who will be staining now did a very light power wash, saying it should be light because its new wood and that it’s ok to just stain without sanding. Will the mill glaze have disappeared by now sitting in the sun all that time? Also, water doesn’t “bead up” but sort of lies on top in a sheet of water.
Have him use a deck cleaner and wood brightener for prep while pressure washing and that will remove the mill glaze.
I have a smooth cedar deck that is about 1 year old. After I let it cure, I powerwashed it thoroughly, let it dry, then applied one-time wood stain. It looked great right after applying. Then the next day I looked out and saw green discolored spots everywhere which I later found out was due to the mill glaze. This was last Summer. Now that Spring is here, this is my next project. They kindly sent me 2 gallons of stain to re-do my deck. I was instructed to sand the old stain off, then apply their stain and sealer remover to get the rest of it up along with fixing the mill glaze issue. Then power wash, let dry, and re-stain. Since this is quite time consuming and their stain is very expensive, I want to get this right. Can you confirm if I should sand, then apply the remover or should I do this in the opposite order. Any help is appreciated! Thanks!
Do not use OneTie again unless you want to repeat curing issues. Strip off what you can, sand the rest if needed. Brighten all when done.
Can you elaborate on your answer? I called to discuss with them and they said to sand, use their stain and sealer remove anything else along with mill glaze, then apply the stain and that should do the trick.
Nothing else to elaborate on. Their stain has curing issues: https://www.deckstainhelp.com/one-time-wood-deck-stain-review/
I have brand new tongue and groove cedar I’m using for a Seiter ceiling. They are one by sixes. One side is rough one side is smooth from the mill. This sequence of cleaning the word and sending I am a little confused. Do I give it a light sanding with my orbital sander and then scrub it with a wood cleaner and wash it. Or do I scrub it with the wood cleaner now let it dry and then send it and then just brush off The dust or does it require another washing after the sanding. And what grit sandpaper would you use?
There is no reason to sand in your scenario. Just use the cleaner and brightener for prep.
Ok thank you very much.
So scuff sanding after the wood drys from its cleaning isn’t necessary?? And if scuff sanding is beneficial what grit would you use?
And and idea how long it will take for wood to dry enough after cleaning to be ready for stain/sealer? I know humidity has a lot to do with it . I’m in south Florida. It’s always kinda humid
No reason to sand this so no grit is needed. Typically 48 hours after prep to let the wood dry but this does depend on the brand of stain you are using. Humidity does not matter that much.
I am trying to repair / replace rotted boards on a handicap ramp for my mom. I purchased pine deck boards and not knowing anything about mill glaze, I wiped it “clean” and applied BEHR PREMIUM® Solid Color Waterproofing Stain & Sealer. While searching for something else, I just came across this page on mill glaze. Ohhh, never heard of that! So, now my question is – what do I do? I ‘thought’ I was going great at it—- applied the Behr product to all 4 sides. Two coats. So, now, what to do? Thanks for your help.
Nothing you can do now except fix it later down the road.
Yeah, that’s what I figured…. but, was hoping you had some magic. 🙂 Thanks.
For the future . . . . I’m in an area with very high humidity, lots of microburst rain storms in the spring, early summer. So, the ramp can stay pretty wet. I’m thinking that sealing all sides (including the butt ends) would be the way to go…. but, as I’m learning all about letting the wood breathe to dry out — I hate to install, wait for it to dry, then pull it up to seal it all the way around. So, would it be crazy to seal all sides/ends except the top? I know it would look funny, just trying to avoid future double efforts. If the top is exposed to the sun, would that be sufficient to allow it to dry without curling? Thanks.
No need or advantage to staining all sides. Just do exposed areas.
I have a new deck that came with my house purchase. It has been weathering for 1.5 years due to life events and rain. I am trying to stain deck this 2017 Labor Day weekend and came across your mill glaze advice. If I sand the entire deck to remove mill glaze and green mill marks/stamps, do I need to still wait 1 to 4 months? The entire deck should be even right?
I was going to do the following order 1. Powerwash 2. Use deck cleaner 3. Dry for a day 4. Sand entire deck 5. Stain
Is this okay for new decks?
Your deck is not “new” at this point. Your steps are correct though. Do not over sand as it can reduce the stain from soaking in. Try 60-80 grit paper.
Thank you! I forgot to mention that I purchased semitransparent Olympic Redwood Elite stain (requires a day to dry). Elite says lifetime warranty compared to Olympic Maximum (that can be applied on slightly wet deck the same day the deck is cleaned). What voids the warranty? What does such a warranty cover? Is Olympic a good brand?
Also, I purchased a 5 inch Ryobi orbital sander. Do I really need to purchase a 6in orbital sander or rent a floor sander from Home Depot/Lowes? My deck is 16ft x 12ft.
Nothing lasts a “lifetime” and any warranty that claims longer than 2-3 years is BS for a deck.
Not are not fans of Olympic products. Years ago they had some decent stains, but changes in formulations have made it inferior to waht it use to be.
I put pine plank siding on my barn in the snow of December. It has rained and snowed and been 95 degrees on the bare, untreated wood for 7 months. Do I still need to worryworry about mill glaze?
Yes. Prep before staining.
I used an exterior water based stain from Sherwin Williams to stain some new cedar 1×6 tongue and groove cedar boards under a protected patio and some cedar beams it fished eyed on me and even started to run in areas making drip marks way after the stain was applied.
Sherwin Williams wants me to power wash then chemically treat the surfaces using their product called “Resolve” Appling it with a pump sprayer. How long should I wait before re-staining?
You would have to strip it off to remove. Brighten when done. Wait a few months and prep again before staining.
Is it still necessary to open the pores when you are using solid color stain?
Yep.
We're installing a new kdat deck. All info says to clean the mill glaze off first, which means getting it wet. TWP says to wait a full month before applying their stain to kdat wood. My husband insists that we stain immediately and if there is a mill glaze we sand it off. Help!!!
Best to follow TWP\’s directions on this. They will know more on what is best prep.
We had a brand new Cedar deck built in our back yard. The contractor used top-line Olympic stain and applied it via brush. After five months the deck is peeling…parched from the sun. We discovered the deck was not prepped via washing/sanding the Mill Glaze from new wood. What would be the best path to fix and re-stain? i.e. Strip with a product, sand, and can it be re-stained? Do you have a recommendation on stripping product? I really appreciate the advice.
Prep with Restore A Deck stain stripper and pressure washing to remove as much as possible. If needed, sand the rest off if the stripper does not remove all. Brighten all when done. Use a penetrating stain after. TWP or Armstrong Clark.
I am planning on using premium grade pine KDAT 5/4 decking boards for my new deck. I want to use a clear stain/waterproof product. Rain is expected this weekend and my deck builder insists on installing the decking Sat morning before it starts. Since I"m paying a premium for the KDAT I don't want it to get wet before I seal it so I was planning on sealing the boards prior to installing. I'm also not going to have time to clean & brighten the boards before sealing again due to weather forecast. Not ideal situation but that's where I'm at so my question is this: Is the worse thing about not cleaning the new KDAT boards and sealing prior to installation going to be that I may have to retreat the boards in about a year or less? The other question since I'm sealing before installing is I plan on sealing all sides of the boards. Is this ok?
No need to seal all sides. If you do it now, you will have to redo in 9-12 months. Clear sealers will not provide UV protection from graying. You need tint/color in the stain for this. The more you have, the longer it lasts.
Actually my wife likes the grey weather look which is what she's hoping for (matches our house better than the stain colors). It's a small deck so no big deal to recoat each year unless the UV eventually destroys the wood. I'm thinking if the cleaning and brightening step is critical before staining and rain is imminent this weekend would it work to install the boards uncoated and then cover with plastic sheeting until I have a week of sunshine to do the cleaning and staining as recommended? I've read it's best to waterproof/stain after boards are put down anyway. True?
Yes that is correct.
Seal it with a gray tinted sealer.
This info was very helpful. I had two decks replaced the summer of 2015 and the stain did not appear to absorb the stain. Shortly after the initial staining I contacted the contractor saying the decks were "sticky". His response was lets check next Spring (2016). Ugg! After one power wash/cleaning in Spring of 2016 they still appeared to have a film on the floor boards. I have spent a bit of time cleaning and brightening them. I now plan to sand them. Irritated that the very competent builders of the decks were not so competent in the staining process. (My decks are made of untreated cedar.)
Hi, I live in Southeast PA and am using new cedar planks. I'm planning to stain with Cabot Australian Timber Oil in Jarrah Brown. Do you have a recommendation on the type of wood cleaner & brightener to use? I've noticed that several products indicate that they're both a cleaner and a brightener, but the above article suggests a 2-step process. What's your recommendation?
Cleaner and brighteners as supposed to be separate products when done correctly. We use Restore A Deck Products.
We are building a new house with a wraparound porch. We had planned on using a composite decking but a friend works for a building supply company recommended we use western cedar. We would like to stain it in a dark mahogany color not the natural color of the wood. What type of stain would you suggest for this. I have researched composites and I haven't found anything appealing about it.
We like Western Red Cedar and that is what most of our clients have. Hard to get it to a dark mahogany color though. You can get it fairly dark brown with TWP in Dark Oak color.
I sanded new deck to get off black ink prints and color of wood lightened will it darken back or have I ruined it?
Let is sit for a month then clean and brighten for final prep and you will be good to stain.
Hi, new redwood deck in California.
Need to be stained , the price is high from outside contractors, plan to do it by ourselves,running out of money.
We will use cleaner and brightener by Super deck , the good brand like RDA should be ordered online. The stain that we will use,is Armstrong Clark in Red wood tone.
Should we use something extra product for removing the mill glaze?
Any suggestion?
Thanks
The cleaner and brightener will remove the mill glaze.
new PTW deck installed Nov 2014. rough cold snowy winter. Contractor plans to stain/seal this spring, but declined to use cleaner and/or brightener despite numerous recommendations. Any thoughts? Are cleaners and brighteners just gimmicks?
No they are not gimmicks. That is ridiculous to say. Washing with water alone can damage your wood extensively if done with too much pressure. Prepping products make it easier, better and gentler for the cleaning process. In addition on new wood they will help to remove the mill glaze and open the grain better for the stain to absorb. Your contractor is not very well versed on the subject. I am sure he does good work but he is missing the value.
We have 20 year old deck in back of our house that was stained with Deckscapes solid acrylic stain 2 years ago. There was some peeling, especially some replacement boards we had put in. After reading your site, I am sure they had the mill finish, because the stain didn't adhere well. I pressure washed 5 weeks ago, and there are 4 or 5 boards with some soft wood that need replacing, plus exposed wood on many others where the stain peeled. We are near Seattle, WA, so there will be rain all Fall, Winter and Spring, but we have a week of sunny weather coming up, with time to prep this weekend.
Should we wait to replace the soft boards, then prep and stain everything this week? Or should we wait to replace the boards and do those when and if things dry out next summer? What stain do we use for Washington State's VOC requirements? Thanks so much for your help!
I would replace now, prep and stain with another solid stain acrylic. Problem is the base coat is still going to be the SW solid and that will continue to peel on the floors. The only way to fix is to remove and that will require sanding it all off which is very hard.
We are sanding. I want to correct my first post–the Sherwin Williams Deckscapes was put on 5 years ago, not 2 years ago, so it held up pretty well. Since we're sanding anyway, we're going to use the TWP 100 oil-based stain. Thanks for your help!
We just finished building a pressure treated deck. Full sun in northern Virginia. How long should we wait to clean and stain the deck? If we wait three months, we are into November, so is it better to wait until Spring? Would you recommend TWP 100 or TWP 1500? Or something else? Thank you so much.
Please read this: https://www.deckstainhelp.com/staining-a-new-deck/