Hi there – I took these pictures last weekend for you to look at. I cannot find the original topic on the website so here they are. The deck was stripped, sanded and stained in September and the black is starting already!! Actually it started 2 months after we had it done. The deck is 10’deel and 32’ long, if that matters. It is facing east – southeast. We are in Maine. I am going to start a new post also. Thanks for the help. I can only post 3 pictures so I will add a couple more in the next post.
Here are more
I would like to ask you a few questions to help us figure out what is going on.
1:What kind of finish did you strip off of the deck?
2:How long after stripping and sanding did you wait to apply the new product? Did you wash the deck after sanding?
3:What grit of sand paper did you use?
4:What was the weather like when you applied the new deck finish?
5:What deck finish product are we looking at in these pictures?
6:How did you apply this deck finish?
7:What kind of foot traffic has the deck had since September?
8:Is the deck covered?
9:Did you do the work yourself, or hire a contractor?
These questions should help people figure out what is going on here and how to help you figure out what to do about it.
Kevin, PCS Redmond
I paid to get it done "professionally" - the first time the builder had it done and then we had to get it re-done because he used the wrong stuff (said - not for decks!)
1. The original stain was not for decks [ Cabot Semi-Transparent Oil - color was Ochre. We picked the color and he was supposed to know what he was doing.
2. a day or so
3. no clue - electric rotary hand sander I think
4. Weather was beautiful
5. Sherwin Williams custom tint - supposed to be similar to Woodguard (?) It says
Gallon A18C850 DKSCPS Oil St Tint
6. He strayed it on and then brushed it in
7. It is just the two of us so not that much. Snow shoveled off this winter.
9. Hired a "Contractor" He wanted us to do the whole house - thank god we did not fall for that one!
I would say the biggest unknown would be, what did you do to treat the deck after the sanding? Sanding and blasting alone will not kill the unseen algae, mold/mildew spores just underneath the surface. It will not neutralize the pH levels. If that treatment wasn't done, mold and mildew will grow as you are applying the stains, especialy if the stains have insufficient mildewcides, and it will be behind the stains. Also, I would reccomend staying away from Sherwin Williams deck stains.
All I know is that he stripped, sanded and then stained - not sure if he did anything in between that. The proposal says:
1. Clean and strip existing finish on deck, stairs, and rails
2. Stain deck, stairs and rails
Maybe I should email him and ask him what he "cleaned" it with?? Thoughts?
You could do that, or you could get a heavy duty mold killing/ neutralizing cleaning compound ( I prefer Lovitt's two step cleaner and brightener) and see if you can wash out the black. If it washes out, you just need recoated.
If you don't want the hassle of test washing, just find out exactly what was done to prep (products, methods ect.) after the sanding was done.
just need recoated.
Does this mean re-staining?? What can I use instead of the Sherwin Williams?? I would probably never get the same color again.
Yes, I was referring to re-staining.
I would probably have to advice to use the same product, if you re-coat, or at least have you consult with Sherwin Williams about what other brands/colors are compatible.
Thanks for the advice. I sent the contractor an email - we shall see what happens.
Still have not heard from the contractor. Not surprised.
Just got an email. He has no idea what happened. Here is what he said.
"I have no idea why the deck looks like that, the only thing I can think of that may cause that is moisture for long periods of time, like snow or ice just being in place, rather than keeping the deck cleared off, that would be my guess, but not 100% certain.
We used a Behr premium stripper for the removal, which we use on all decks, then sand and stain.
That's always been the process and never had any problems with the finish."
We do clear any snow off but it might be a couple of days before we get up there. FYI - we had almost no snow this year - compared to other years so I don;t really think it is that. This issue started before the snow started to fly!
Below is what I emailed to you earlier this morning:
Let me just say: the mold/mildew issue you have is fairly common, but preventable in the future. Ray is right – when not treated before staining, there’s really no way of preventing mold and mildew growth. And here’s the kicker: even if you’re able to kill the mold “through” the stain, as Ray suggests you try, you will most likely do considerable damage to your stain to the point that, in a few more months, it will need to be stripped off and re-stained. We are never very fond of people sealing over mold/mildew, even if it does appear to have been killed. Too much risk there. In my opinion, it would probably be worth it to you to have it re-done, but having these different things done:
1) Get a moisture meter. You can find ones that work good enough on Amazon.com or HarborFreight.com. It’s a tool every log home owner should have in his/her toolbox.
2) Check the moisture content of your wood prior to doing any work. This will give you a jumping off point. You wood may still be a little wet (as evidenced by the mold/mildew growth) so you’ll want to be sure that the deck is back down to your original measurement or lower before applying more stain.
3) Sand, don’t power wash, the surface. Adding water to an existing water-induced problem only exacerbates the situation. Plus, you’ll have to use water in steps #4 and 5 below….
4) Make sure whoever does the job cleans the surface with either an oxygenated bleach cleaner or 4 parts water to 1 part bleach solution to kill the mold. (Be aware – high-tannin woods like redwood and cedar can be discolored by any cleaner and may require extra neutralization. Let me know if you need more details on that.)
5) THOROUGHLY rinse to remove the cleaner. Any cleaner left behind will damage the lignin in the wood cells. Lignin is the glue that holds the cells together. Damaged lignin looks like flaking stain, but is really flaking wood with stain on top of it.
6) Allow your wood to thoroughly dry. For many people, that means prep one weekend, stain the next. Here in Colorado or in southern Arizona, where it’s super dry most of the time, that could mean only 2 days. For you, I’d stick with the 1 week. BUT, to be sure...
7) Check that moisture content with your moisture meter before you begin. J Make sure you’re back to where you started or lower.
8) Stain using a product that has some film to it to prevent UV damage, but not a thick film that can be easily damaged by foot traffic, furniture, etc. Sashco just launched a deck stain called Transformation Deck & Fence (new to you, not to us - in tests for about 5 years now). But, as I always say, don’t take my word for it. There are other good deck stains out there so do your research and see what you find.
9) When you apply your stain, be sure to add extra mildewcides to it to help prevent mold and mildew growth on the surface. We like a product called Stay Clean I/E by Walla Walla Environmental. It’s easy to use and fairly inexpensive (about $5 for the amount needed in a 1 gal. bucket).
10)Don’t apply the stain in direct sunlight and be sure you have surface and air temps that are between 40-90F, including overnite temps, both while applying the stain and for 24-48 hours after you’re done staining. Applying stain in direct sunlight or to a surface that is too hot or too cold can cause it to dry too quickly or too slowly and, in both cases, prevent proper penetration. Applying in air temps that are too cold or too hot will do the same thing. You can get cheap surface thermometers on both amazon.com and harborfreight.com to make sure you’re within that range.
It seems like a lot, but all of these little steps of ensuring proper prep will mean the difference between a 6 mos. life on your deck stain (and having to strip and re-stain each time you have to do maintenance) or 2 year life with maintenance being a simple power wash and re-coat.
I hope that helps some and thank you for giving me a chance to respond. Please let me know if you have any further questions.
Have a great day!
Charis w/ Sashco - www.sashco.com - firstname.lastname@example.org