I regularly get questions about staining pressure treated lumber so here are some answers to as many of those questions as I can think of now. Before you read on, understand that staining or painting pressure treated lumber is just like staining untreated lumber. The main thing is that the wood needs to be clean and dry.
Can I stain pressure treated lumber?
Yes. You can stain pressure treated lumber as long as the wood is dry.
Why do I have to wait before staining pressure treated lumber?
The pressure treating process involves using a water-based solution to carry the treatment chemicals into the fibers of the lumber while under pressure. The process leaves the wood wet. If you want wood that is already dry, purchase KDAT lumber (KDAT = Kiln Dried After Treatment). KDAT is usually #1 and, yes, it costs more.
What are the consequences of staining pressure treated wood before it’s dry?
The stain or paint will probably bubble a little AND locking moisture into the wood might create a great place for fungus or rot to take hold and destroy some boards.
How long should I wait (allow the wood to dry) before staining pressure treated lumber?
It depends (of course). In a sunny, hot, and windy climate where it never rains your pressure treated lumber will probably be dry in a few weeks. In a cold and muggy climate (Seattle, for instance) it will take months for your wood to dry.
Some professionals recommend building whatever you are building and waiting about six months before staining pressure treated lumber. Then, stain the lumber after a few weeks of warm sunny weather. This is long enough for the wood to stabilize and for the water from treatment to evaporate. Remember to sweep and/or dust before applying the stain or paint.
Read further to learn about drying lumber yourself…
What kind of stain should I use for pressure treated lumber?
There are many stains and paints on the market. My favorites are based on working with lumber yards and seeing results from Consumer Reports. So, I like Cabot and Wolman brands. Many people thing Thompsons is the best because their marketing is the best. Many professionals completely disagree with the idea that Thompsons is any good at all. I am not saying anything about it – I’m just sayin’. The choice between water-based and oil-based stains is up to you. Read the backs of the cans. Back to staining pressure treated wood…
How should I stain pressure treated lumber? Or, how should I apply the stain?
Read the can because it varies with some stains but most stains can be applied with a brush, sprayer, or sponge. You will probably find a sprayer to be the easiest method.
How can I speed up the lumber drying process and stain my lumber sooner?
The best way is to buy kiln dried lumber (KDAT) in the first place. If you don’t want to do that…
You can dry lumber yourself but you need to be concerned about warping.
Ideally, you should stack the lumber on “sticks”, in the same way wood is stacked for kiln drying, and then strap the bundle to keep in straight. To do this, place a few small (1×1 or 2×2) sticks between each layer of lumber (perpendicular to the lumber and spaced about 3 feet apart) allowing for air flow between the layers. Then wrap a few straps around the lumber and make them tight. This allows air to reach all sides of the lumber while applying pressure to the lumber and minimizing the chance of warping. Warping is caused by the movement of moisture in and out of wood. You need to stabilize/support the wood while it dries. To take it to another level, point a box fan (or two) at the side of the bundle to speed up the flow of air across the lumber. If you set this up in your garage or some dry covered area your lumber will probably be adequately dry in a few weeks.
Should I stain pressure treated lumber yearly?
The answer is simple and goes something like this. If you want your deck/gazebo/arbor/whatever to look better for longer you should stain it on a yearly, or regular, basis. Of course, putting a protective stain or other coating on wood will make it last longer and look better while it lasts.
Staining pressure treated lumber is not rocket science. In fact, there is nothing remotely complicated about it but it does take time and if you don’t do it properly, you’ll mess it all up. If I did not make this point obvious enough above then let me say it again here:
Treated wood must be dry before you stain or paint it.
Enjoy your project. Wear gloves. Wear goggles. Be careful with tools. Work in ventilated areas.
Hey Chris,
This is a great site! Thanks for all the hard you have put into it and sharing it with us all!
Your comments are very helpful. I had a pressure treated wood deck built in October 2008 and have been searching for information on stains that can be used on the decking. Since the weather here is fairly mild I feel that maybe the deck will be ready to stain next month. I will certainly follow the advice given and read the label on the stain I choose to use. I will also look into your suggestion of the brands you suggest. Thank you again for the infomation.
Glad to help. ENJOY your work!
Chris
Hi Chris–thank you for all the helpful suggestions. I have read on other sites that new pressure treated wood should be ‘sealed’ immediately. Wouldn’t the sealant keep the moisture in the wood rather than allowing it to evaporate?
Also, the wood our carpenter is using was kiln dried prior to the pressure treatment. Does this affect the waiting time to stain or paint the wood?
Hi Amy,
I agree with you. The professional I hang around – from lumberfolks to deck builders – say to wait until the wood dries.
Kiln dried BEFORE pressure treatment? Or after? It is common for wood to be dried AFTER. Kiln drying before treatment is sometimes done to ensure deep penetration of the chemicals into the fibers of the wood by removing the existing water to make space for the water-borne preservatives.
I don’t think it would affect the waiting time. The big factors are still going to be rain, sun, temperature, and humidity.
Take care and thanks for writing.
Chris
Hello Chris,
Does “new”(installed oct 2008) treated decking need to be prepped prior to staining?
Someone mentioned to me that “mill glaze” will have the fibers “smashed down” and
the stain won’t penetrate properly. Is there any truth to that?
Thank you,
George
Mill glaze is really only an issue with redwood and cedar when they are planed with dull blades. Treated pine, which has vertical grains, does not really have a problem with mill glaze.
Always sweep thoroughly and make sure the deck is clear of any dirt, dust, debris, or moisture before staining it.
That’s it. Good question.
Take care,
Chris
Thanks alot Chris,
You just saved me a day and some money, with the weather here in
the Northeast looking good thru next week, looks like I can get some staing
done this weekend
Thanks again,
George
I love saving people money. My commission is 20%. Send the check to…
Glad to help. I hope your project went well.
Chris
I just had a screened in porch built with treated wood. Should I seal it now or should I skip sealing it and wait a few months and then stain it?
What stain would you recommend? Thanks.
Hi Alan,
This is just what I would do – skip the seal and stain later. I like Cabot stains – nice colors, applies well, protects well.
Enjoy!
Chris
Hi Chris,
I just found this website, after searching for weeks. Just had a new deck completed, vinyl railings, PT (pine?) floor. Looks like I’ll have to wait until spring to stain? And is semi-transparent better than solid? (though I like the look of solid better wtih the vinyl railing) and what about semi-solid? I already decided on Cabot. Thanks for your easy to understand info.
my client wants me to seal the underside of the decking boards before i screw them down to prevent warping. although i am willing to do this, i feel it is unnecessary and will have little effect on keeping a predisposed board from warping. the deck will receive a semi-transparent stain and she has asked me to use thomson’s water seal on the bottom-side. what do you think?
I agree that it’s not necessary to coat the underside so state your professional opinion give your advice and then make your client by charging to do what she requested.
Hey Donna,
I don’t know about waiting until spring. You just need to make sure the wood is dry. A few weeks of hot days with no rain and a little breeze for good measure should be good for decking.
Use whatever color you want. Color is required for UV protection which is going to give most of your fade resistance but it all gives great rot/decay protection.
Thanks for reading!
Chris
We applied Cabot semi-solid oil-based decking stain to our deck two years ago. The deck needs a new coat, but we are concerned that the Cabot stain peeled and flaked off in places rather than penetrating the wood. The wood was not new when we stained it. One store advised that we need to “mill” the deck before we apply new stain. I’ve never heard of that before. Another said that we ought to use solid rather than semi-solid stain.
What would you recommend?
Hi George,
Was the wood DRY when you applied the stain? How about clean? If it was applied over spots that were oily, dirty, wet, or otherwise unclean wood you could expect it to flake instead of penetrate.
Solid vs semi-solid shouldn’t matter. In fact, I would expect semi-solid to be better for you but solid probably provides better UV protection.
As for milling, that would help the next coat penetrate the wood better. Think of it like sanding REALLY hard (really really hard).
Hi Chris,
I had the porch replaced with treated wood in the fall. We’re ready to stain when we have dry weather. I want to verify that I do not need to seal.
Thanks,
Gretchen
I have a question. My deck is only 8 months old and the Cabot stain the contracdtor applied is fading and in some spots has mildew. I am in Florida and it has been
very hot but today I noticed sap has risen up on one of the boards. How do I get rid of the sap on the decking?
Chris,
I have a 21 year-old wood deck, which has been stained red at least 6 times. I want to use a new stain product called “Restore Liquid Armor Resurfacer” (made by Synta Inc.), which has a grit particle finish to fill in cracks and nicks. I scraped off all of the prior coats of red stain, but found some boards with severe surface problems. I had to replace 30% with new pressure treated lumber. Right now, my deck is a combination of old PTL scraped down to bare wood and new PTL. Is there a way to pre-treat the new PTL (sanding, pressure washing, etc.) such that I can apply this new stain product without having to wait 6 months for the new PTL to dry out to allow the new stain to adhere? If not, should I apply a coat of wood waterproofing to the scraped old wood in the meantime and simply wait until next spring? I live in Pittsburgh, which has a high humidity level in the late summer. Any advice is appreciated. Thanks.
I am really late to this post but it’s a great question. Sap seeping out in hot weather on relatively new decks is a common problem. Use a clear oil (like Canola oil) to get it off or use something like Goo-Gone, which is an awesome product you should have around anyway.
By the way, if you get sap on your hands, the quickest way to remove it is by washing your hands with motor oil. Yeah, gross, and then you have to clean motor oil off your hands but that comes off with soap (which comes off with water).
It works!
I think someone left out the word “wet.” Because your deck was made of “wet” pressure treated wood… The deck needs to dry thoroughly before adding stain. For the wood to properly dry, you will need 4 to 6 weeks of pretty dry, hot weather. If you live in TX where I live, this should be no problem for you this year.
Hi Jerome,
It SOUNDS to me like the pressure treated wood was not dry. The time you wait (6 weeks, 8 weeks, or 2 years) is not as important as the dryness of the wood. Usually, 6 or 8 weeks with sunny, dry weather is enough — wind helps, too.
I think you’ve got the right idea. At this point I would sand, let the wood dry thoroughly, and re-stain with [whatever you want to use].
I know that doesn’t help much but it’s all I’ve got.
Chris