Cedar Siding

Got a call to clean some cedar siding, he said some of it is black. What do you guys do for Cedar siding? any chemicals, should I be extra careful?

Does he just want it cleaned? Cleaned so he can stain? Or cleaned and stained by you?

I would use sodium percarbonate, clean between 500-1000 psi, neutralize with oxalic acid. Wait a day then stain.
Maybe you can mix the percarb with some roof snot

I’m not huge into wood restoration so maybe someone else will chime in with a better answer.

We pretty much hit all Cedar houses that are black from mold/mildew over the years with a stripper and a brightener to make the Cedar look new when where done. Some Cedar houses we seal like one where doing next week(good money in sealing houses) some we stain only with transparent stains and some Cedar house we clean only which is decent money in that as well.

Wood restoration is the most magical thing to see in this industry. When you are finished and then you hit the wood with an Oxalic acid(neutralizer/brightener) it’s like magic before your eyes watching the wood brighten up.

how long do you wait for the neutralizer? what happens if you don;t use it? I used percarb to clean some cedar shake siding, rinsed the crap out of it, and brushed it, then rinsed some more. is neutralizer needed?

Depends who you talk to. If we’re cleaning a house with a solid stain on it just to clean it we never use neutralizer but if we’re cleaning a cedar sided house that had a transparent stain on it that has turned grey or black we strip then neutralize. Sometimes we may use a bleach mixture for a deck that may have never been stained and we still neutralize it. The neutralizer is the magic. The other stuff such as the hydroxide throws the PH of the wood off to where it blackens even more so you clean out much easier what’s in the cedar such as the failing stain. Then when you hit it with the neutralizer the wood magically before your eyes begins to brighten because your bringing back the correct PH of the wood.

When dried the wood will be as clean and bright as it can get… The neutralizer and in our case it’s the Oxalic acid is the most phenomenal thing I ever seen work in all the types of Powerwashing we do that has a sudden impact like it does during a wood restoration project… So we neutralize just about all the time.


He wants to seal it himself it does have black all over one side of it. Do you mind explaining the process/chemicals you use? Is it a type of softwash or does it need high pressure ETC

No never high pressure on wood restoration. Since you have the guy who wants to seal it himself that’s my favorite type of job because we schedule jobs in for the week in advance. There isn’t to much wiggle room and when there is staining/sealing etc and the day turns out where there’s a potential for rain it can throw our schedule out of wack. We travel in pretty much with the “50” mile rule for residential. So jobs get schedule by location.

Now for your answer. Pick the side of the house away from the Sun and try to do the house sides in order where the least amount of sun will hit it while cleaning. So now you have your side. Rinse everything from the garden to the house and windows and back on the garden. Since we use high volume water we saturate the house and garden. Now Make your stripper(actually have it made right before soaking house and then mix it a little more right before applying) as strong as possible where you put in the max amount of stripper into a 5 gallon bucket and mix it up good here. Attach an x-jet to the bucket (we use tanks and dollies for this) and begin to spray the stripper bottom up and then go top down this way you know the wood is saturated with the stripper and don’t forget the x-jet is cutting your mixture another 66% which is why you need to make it max strength. Now rinse the garden some more and spray the windows a little bit to keep the solution off of them. Make sure you don’t let the wood dry with the stripper on it so mist the siding every now and then.

So after about 10-15 minutes start from top down and spray around 5-10inches from the house with a white 40degree tip. Make sure your spraying straight at the cedar because if you spray up on it you could knock out a few Cedar shingles.

Remember the stripper is doing most of the work so do not use to much pressure which is the reason I say keep the tip spray that far away from the wood(we use high volume water here to so our fan spray is much more pronounced. Now when that done we generally do all sides of the house first with the stripper and rinse rinse and rinse some more is key.

Then the side we finished on we now spray that side with the neutralizer (Oxalic acid in our case). We rinse the garden and windows so nothing dries on them. This is the amazing process here because you can see the house start to brighten up. Then go to the next side and rinse the wood wet some and then do the same thing to it with the brightener. Do all sides of the house this way and then go back from the first side you put the Oxalic on and do a quick rinse top down and all over the place for each side again. This goes faster then you think. Rinsing a house is easy compared to rinsing a parking garage which is mostly a flat surface where dirt doesnt move to easily(another reason why we have high volume Powerwashers)

Follow the above procedure and you will find gold in cleaning cedarshake, cedar planks type houses.

Good luck and make some bank;)


Wow, great reply! When cleaning that type of siding or a roof, do you use a lift most times or scaffolding?

We have used lifts and scaffolding but most of the time we use ladders for cedar shake siding. Also when it comes to roofs we use ladders and Harnesses and ropes when needed. I’ll give you a ladder tip… First off all of our ladders are Werner Ladders which last forever and are super durable. Here’s the tip we use Ladder Stabilizers Werner - Quick Click Standoff | Bird Ladder so the ladder itself is away from the house. This way when your up there you can power wash right in front of the ladder. You can even bounce the ladder away from the house ever so slightly so you can hit then spots under the stabilizer. They also sell adjustable stabilizers so your further away from the house and you can now powerwash without bending you back and holding the wand in an uncomfortable position.

If I go on my laptop I’ll show you guys some pics of us doing some Cedar sided houses.
Tomorrow one of the 3 jobs where doing is sealing a house front that was 3 sides vinyl and front Cedar that we did last week.
Friday where stripping another full cedar sided house and next Tuesday where schedule to seal it…

These jobs are gold.

Here’s a couple of pictures. I generally don’t take to many pictures anymore because I’m rarely there. Here’s a few that are on my laptop from the last couple of years.

Some more pics. The above house is from a well known Chef that lives out in the Hamptons. His house just goes and goes and is much bigger then in the pics I show above.

These pictures here are from another house in the Hamptons that was a nice pay day.
Before,during and after pics. See how far the powerwashing spray is to the siding on the house? Thats about as close as we go.

Some more pics,

Thanks for the info John.

Can you provide some input on what you see in the attached pics? I’m not sure what or when the finish was applied.

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Beautiful work!

It looks like there was a transparent stain/Sealer applied to that house anywhere from 3-5yrs ago. If it was a Behr product they could could turn black in less then 2 yrs. There stain a few years back was in a class action lawsuit because it was garbage. But on that house your showing it looks to be about 4+yrs when there was something put on it.
I would strip that out where it would look new when done and then apply a sealer with a tint of Cedar color to it which my guys did today. The problem now I’m having is the main natural stain I’ve been using for years is going towards being garbage because of the VOC changes here. The natural stain we use is the Cabots natural. Its now like a Hyrbrid where you can clean up with water the first half hour and then after that you need a thinner… It goes on a pinkish color now. Were stripping another house tomorrow and sealing it next week with the same stuff…
Time for me to start looking for another product.
Here’s some pics with my camera today. This camera is biting the dust as well. The pics look hazy. Time to get a new camera as well. If its not one thing then its another.

Here’s a house we stripped today. Where schedule to stain this Tuesday or Wed(July 4th) of next week. It looks like where going to use Benjamin Moore Natural. These are basically the only house we do now where they want a natural stain/Sealer on them. We may do one or two Houses a year where they want a Semi transparent color. All Solid stains we stopped doing years ago. They weren’t worth the money because of all the time they take to do with Primers etc.

I have a question regarding spray washing a cedar home to remove old stain. We have a 15 year cedar home that was restrained about 5 years ago for the first time. We waited to long and much to our disappointment, staining it turned it from a light reddish color to a brown. We were approached by a company called Nu Wood2 and they claim they can power wash the home and restore it to its natural beautiful red color with re-staining when clean. Do you believe that is true? Will it damage the wood? I have read conflicting reports and am nervous about doing something that will destroy our wood siding. Thanks very much!

I have a question regarding high pressure spray washing a cedar home to remove old stain. We have a 15 year cedar home that was restained about 5 years ago. We waited too long from the original staining and much to our disappointment, it turned it from a light reddish color to a dingy brown. We were approached by a company called Nu Wood2 and they claim they can high power wash the home (use chemicals if necessary) and restore it to its natural beautiful red color with re-staining when clean. Do you believe that is true? Will it damage the wood? I have read conflicting reports and am nervous about doing something that will destroy our wood siding. We are having trouble finding anyone who can help us restore the wood. Most of the local contractors say we will have to paint the wood and we really don’t want to do that. Thanks very much!

here is a home I did just last week all low pressure. I do not do a lot of these but everything I have done is by low pressure. It is ready for stain now.

Wash Authority

Can a cedar siding home just be cleaned, without stripping & restraining

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