This post was updated on May 1, 2024
Moisture Content of Wood for Deck Stain
We here at Deckstainhelp.com remain committed to being your source for industry insights and trends for the perfect deck stain. Please note that your deck should be dried for a few days prior to stain application following prep, excluding Restore-A-Deck stain, which can be applied on the same day as the prep. We encourage comments so feel free to leave us one below.
What Should Be the Moisture Content of Deck When Applying Stain?
A deck staining project is something any do it yourself enthusiast can accomplish. Most of what needs to be done can be found online on how-to articles. Cleaning the deck with the proper chemicals and methods is crucial. However, after the deck is cleaned and ready to be stained there are a few things to consider that can make or break the success of the project.
Once a deck is cleaned it should be allowed to dry for several days before the stain is applied. Most stain manufacturers have recommended drying times that may vary slightly. In addition to varying recommendations, other factors like weather, sun exposure, wood type, wood age, and porosity can also determine the exact amount of dry time a deck needs when applying the stain. When all things are taken into account, it would seem logical to wait a long enough period so there is nothing left to chance. So what should be the moisture content of the deck when applying the stain?
On average most stain manufacturers are going to recommend that the deck’s moisture content be anywhere from 12% to 15% or less. Otherwise staining a deck that has much higher moisture content can cause all sorts of problems. Stain or sealer will essentially lock unwanted moisture in the wood which then makes it prone to mold, mildew, and fungi. From there, wood rot and decay would be likely. This can jeopardize the structural integrity of the deck and end up causing costly premature repairs and replacements.
Waiting several days for a deck to dry after it has been washed is your best bet. If it rains in between that time, waiting another few days for the wood to dry again is recommended. When a deck is brand new the moisture content is very high. A new deck should be allowed to season for 3-12 months prior to staining. To know exactly what the moisture content is you can use a moisture meter. Check the moisture content of a deck in several areas and take an average reading. Be sure it is below the recommended moisture content before proceeding with applying the stain.
I have a 13-year-old pressure treated deck. I have replaced several boards a year ago and also some additional boards six months ago. I have stripped and used brightener. Then I sanded everything and brightener again. I am ready to stain. I reviewed TWP 100 pro series semi solid application steps today. It said that pressure treated needs 12 months before application. Not sure what to do about the boards that are only 6 months old. I understand that there will be differences with the aged wood but I really need to get the other boards stained. Should I just wait another six months for the recently replaced boards? Stain them if they pass the water test? It has been 48 hours no rain and the weather looks good. I’m going to start on the verticals tomorrow. Appreciate your advice as always.
You do not have to wait 12 months for new wood with TWP Stains. 6-12 months for the semi-solid TWP. You should be fine.
If the moisture content of our project deck is 50% or gouged in some areas. Is there anything we can do for the customer to get their deck coated?
We do not know of a way to manually speed up the drying out of a deck so that moisture % is less than 15%. It has to do this on its own.
I have a pressure treated wood deck that is about 21 months old and never stained (installed July 2020). We just extended in another 12×16 feet at the end of April 2022. Would you suggest waiting about 3 months for the new deck to dry out and stain it all at the same time? Or will it be better to stain the old part first and give the new part even longer to dry out before staining it? I assume it may look a little different given the age difference but I’m hoping to get them as close as possible when stained.
Yes, wait and do it all in late Summer or Fall.
I pressure washed my 13 year old pressure treated southern yellow pine deck 2 months ago and I still can’t get moisture reading below 30% in some of the boards. I am using 59 for the density/gravity spec. Do I still need to wait to apply alykd/acrylic solid stain. Old boards seem porous, but meter says 30%.
You should be fine to stain.
Thanks–can I apply the alkyd/acrylic with a night time temp down to 45-(day in low 70’s)?
Yes.
Will the cleaning process on my newly constructed pressure treated wood deck get rid of the mold (the contractor used inferior lumber). Also what type of person do I need to contact to prep, stain the deck when the wood has dried out?
Cleaning will remove the mold and mildew. Find a deck restoration contractor.
Easier said than done I’m afraid. Any suggestions as to restoration contractor? I live in Greenwich Connecticut. Secondly I’m very impressed with your reply and your website.
Where would I find a reputable deck restoration contractor. I live in Greenwich, CT.
Search online for your area.
Thank you for your speedy replies. I am very impressed with your website. Lastly, is it necessary to sand the newly constructed pressure treated deck before cleaning, brightening and staining?
No need.
Hello. I have a new pressure treated pine deck. Contractor came out sanded deck and then told me after sanding that the wood still had moisture in it. He is recommending that we wait until March/April to seal it??!! Never did he mention this before. I know that the wood needs time to dry, but should he have not sanded if it still had moisture? Also, what will be the condition of the wood next spring after being exposed to the elements for that long? It will be exposed to rain, snow, ice. He’s coming out with a moisture meter to check if moisture is less than 15%. Thanks for any help. I’ve had a challenging time with this contractor.
See this for new wood tips: https://www.deckstainhelp.com/staining-a-new-deck/
Thank you for the response. Well, the contractor did sand the wood on my new deck. I still don’t have a clear answer about what to do. He sanded it, it still has moisture. Is it going to be in worse shape if I let it season until March/April. Thanks.
It will be fine to leave until spring.
We honestly can’t catch a break here! We finished prepping our kiln dried cedar deck Wednesday night. The weather was supposed to be dry all through to Monday. The last 2 nights we’ve had light rain that hasn’t been in the forecast, but apparently is picked up on the radar. The deck looks very dry in the afternoons. Do we now have to wait until Sunday to start staining? Using Armstrong Clark. Original plan was Saturday (tomorrow) as a full day of rain is expected on Monday.
48 hours after rain to stain with AC is correct.
I have a weird scenario and I was hoping for some advice.
Quick question: Will tenting the entire deck after cleaning ever allow for the water moisture to reach the manuf recommended moisture level? Outside moisture is ~80-90% due to rain and general humidity. No real sun due to rain, rain rain. Will a dehumidifier help even with 4-6′ openings or if I choose to close it down completely.
Will the stain dry properly under the tent or does it require sun?
Longer version:
I have a 15 year old deck (mix of pressure treated decking and pine railings) that was only ever thompson sealed and cleaned every 1-2 years. This year, I want to apply TWP 1500 and I used the RAD cleaner to clean and brighten.
Unfortunately, it is summer and I clearly did not do enough research after hiring the contractor from a mix of 8 that came to the house. He is pressuring me to apply the stain and throwing out that he is the professional and everything will be fine, but we have had rain, rain, rain and the humidity is extremely high – 87% or so. The deck is raised and I drainage is not great, so there is likely a lot of moist soil under the deck.
I have a moisture meter and the pressure decking has never reached under 87% (most 100%) and the railings/spindles are between 37-60%. This reading was taken after 48 hours in an area that did not get hit by the light rain.
Last night, I gave up and tented the entire deck with a 30×50′ tarp as the forecast is rain/thunderstorms for the next two weeks off/on. There I have a 12×12′ upper deck with a 25×12′ (roughly) bottom, so that made this possible, but it did rain lightly before I tented the deck.
Tomorrow and after should be mid 80’s with ~42% humidity, but generally speaking storms pretty much for the next 10 days.
Thank you kindly!
Do not tent a deck. It needs air to dry correctly. I think your readings are wrong. Never seen a deck have a higher than 20% reading after 48 hours of drying. Honestly, we do not even bother with readings anymore when using TWP. Just make sure it has no rain for 48 hours and then stain.
Thank you for your guidance! From my perspective, I really have no choice but to keep the tent up or tear it down and wait until fall and start over with cleaning/brightening. Rain is forecast ed for at least every other day for the next 10 days and my understanding is that I really need to wait 12-48 hours after applying or the water can/will displace the TWP? Also, since the wood is already damp it might make things worse given the oil would not soak in.
The deck moisture (rails) was already 32%+ before the cleaning / without rain. That said, the moisture levels are coming down a bit with the main decking at 77% in may areas. I do have a pretty fair natural breeze with 3-10 mph winds all day and as mentioned the tent is between 2.5-5′ off the ground depending on what I attached it to, so it feels like it should have air to dry.
If you were curious I posted a single picture from within the deck tent and the deck is 3.5′ off the ground.
Thank you again!
Ben
TWP can take a rain in about 12 hours after applying. Tenting looks good!
I’ve prepped a 30-year old cedar deck and have been waiting for a stretch of dry weather. It’s been a couple weeks.
Finally got a dry stretch but the wood is still measuring around 16-17% in most spots, give or take a few % depending on where I measure. It’s actually been 3 dry days now, so wondering if that’s about as good as it’s going to get.
Is this normal for old cedar in partial shade (temps in the low 60s)?
Looking at a 5% chance of rain the next few days, so I can roll the dice if 16-17% is really too high.
You will be fine with this.
Thanks! Really appreciate your advice on this site.
The information answered my question and was very helpful. Great job!
Thanks. Just what I needed to know.
I have a new deck built and I’m waiting for it to season before staining. However, there are a couple of cracks showing as the deck is settling. Should i repair these cracks immediately or should i wait till its closer to cleaning/staining period before making those minor repairs?
Leave them alone. Cracks are normal for exterior wood. Nothing you can do to prevent them or fix them. Never use filler, it will not work with semi-transaperent stains.
I noticed that I needed to check the moisture at 20 places to get an accurate reading. Moisture averaged 8% but in two places it was 30%. Gotta wait a while more. Thanks for the good advice.