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Kelly Lee

If cleaning cedar shakes that have been stained, should SH be used? If not then what...

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Check with your chem supplier on the Percarb. I buy it in 50 lb bags for about $60.

As for no SH...the arguements go back and forth, pro and against, hot and heavy on the PWI forum. High caliber guys on both sides make good arguments. My feeling is that of the shingles are severely neglected, have tonnage of moss, algae, mold and lichen on them, then SH vs Hydroxide....better the devil I know. The argument is made that SH will strip the top lignin layer off the shingle, and that is absolutely true. However, Hydroxide is used in pulp mills to separate wood fibers....so it does exactly the same thing. Percarb won't strip the fibers,mbut it is also not often strong enough to kill heavy layers of moss, algae, and molds on shingles effectively.

There are also as a many arguments going back and forth about pressure rinsing....using a power washer to rinse off the stripped lignin layer and remaining dead algae/.moss/molds. If you need to resort to something strong enough to strip the lignin off, then it may be necessary. A high flow machine with a 40 degree tip.

Remember, if you do need to do so, safety is paramount. Cedar treated with SH is second only to a metal roof with soap on it for being a slippery hazard. Corkers are a must. An articulating lift is a good idea.

Get the Oxalic on there in a reasonable amount of time. It brightens the wood and also neutralizes the strong basic action of the SH or Hydroxide.

If, on the other hand, the shingles are in reasonable shape, stick with Percarb.

No matter what...the consensus with the wood guys is that of the wood is stripped, it needs to be oiled/treated after this. Anything which strips the wood leaves it exposed to rapid drying and cracking/.shrinking. It must be treated with an oil to rehydrate the wood and protect it. We use Chevron shingle oil.

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Waiting for Bruce to contribute.............

I don't post much on the forums, other than promotional stuff, some subjects tend to turn into debates more than informative feedback. 

 

That said. This is a subject that comes up a lot. As to the proper solution(s) to use, that is a matter of what works for the provider. Cleaning a stained cedar roof shouldn't be an issue, depending on the stain that was used, it's base, brand, how old it is, etc.

 

It comes down to about three possibilities, sodium per carbonate, sodium hypochlorite, citrus cleaner. Each has it own property and application. The cleaner needs to use what works best for them.

Though understand these are just the base chemical for cleaning cedar, there are other ingredients/chemicals added for an effective cedar roof cleaning.

Also, each has it's own process/technique that needs to be used.

 

The two most common cleaners, base wise, is sodium per carbonate-oxygenized bleach-power and sodium hypochlorite-pool chlorine/bleach-liquid. Both have their own ratio to mix.

The debate continues as to which is proper.

 

The internet is full of advice, which tends to come from many who have none or little experience cleaning cedar roofs. Mostly what they read on the internet, which should be taken with a grain of salt.

 

I have personally tried many different cleaners and combinations of such, each has it's own effectiveness but some work better and are more effective. It's a matter of experimenting and using what works best for you.

I can tell you from the hundreds of cedar roofs I have cleaned, no one fits all. Then again no two cedar roofs are the same!

 

There is a lot more to cleaning cedar roofs than just the cleaner. The grade of the shake, the infestation(s) on the shakes, the installation of the roof, etc.

 

The cleaning of cedar shakes is a three step process and the only process I use, 1.) there is no harm to the roof or shakes, 2.) safely removes all algae, moss, mold, mildew, lichen and fungi and extends the lifespan of the roof, 3.) the customer is always satisfied with the results.

 

So whatever cleaning solution will meet the above three step process I advice using.

 

As to removing or cleaning a stained roof, I don't know what your goal is for sure or which one, but cleaning you can use any of the above cleaners, removing stain is another subject.

 

One last point:

 

Of all the roofing materials, which one or the only one, that is WELL documented " has to be maintained"? CEDAR SHAKES! 

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The job was not on the roof but on the front facing gable of the home.  The home is only a few years old and so they were not in that bad of shape.  The customer just wanted them cleaned with the rest of the house.  I went with the sodium precarb as the cleaner and I think it turned out great.  The customer was pleased with the results and so was I being that it was my first cleaning of anything cedar.  We do not have may home with cedar roofing or siding in southeast Georgia. Thanks again for all the info.  i don't know what I would have done without this RCIA!!  I tried to attach pics but could not make it happen, they are in the gallery you if care to view them.

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No bleach on wood.

 

Not on teak.

Not on pine

Not on ipe

Not on mahgoney

Not on cedar

 

This misinformation on this topic is mind blowing.....

Chemically, Why would SH be any different than Hydroxide on the Cedar? Both strip fibers. Do you find hydroxide is less drying to the cedar?

I've also heard guys say absolutely no pressure on cedar. And yes,mwith the wrong setup and an inexperienced operator, it would be easy to damage the cedar, and more importantly,mthe underlayment. Yet with the moss we get around here, Percarb simply isn't strong enough to remove embedded moss and Lichen. SH works on moss and lichen specifically because it breaks down the Lignin, making it soft. Using only Percarb, you would need to go to pressure.

The house you did there turned out gorgeous, but I noticed very little moss on the before picture. If that is what you are primarily dealing with, then I can see Percarb and light hydroxide being your go to chems. But when you have heavy moss, then what? Go to Zinc Sulfate in a 4 step, and what is the effect of that on cedar?

Simply trying to understand your argument.

And we are waiting Anxiously for Bruce to release his Cedar clewning program as I understand his does well on everything.

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Chemically, Why would SH be any different than Hydroxide on the Cedar? Both strip fibers. Do you find hydroxide is less drying to the cedar?

I've also heard guys say absolutely no pressure on cedar. And yes,mwith the wrong setup and an inexperienced operator, it would be easy to damage the cedar, and more importantly,mthe underlayment. Yet with the moss we get around here, Percarb simply isn't strong enough to remove embedded moss and Lichen. SH works on moss and lichen specifically because it breaks down the Lignin, making it soft. Using only Percarb, you would need to go to pressure.

The house you did there turned out gorgeous, but I noticed very little moss on the before picture. If that is what you are primarily dealing with, then I can see Percarb and light hydroxide being your go to chems. But when you have heavy moss, then what? Go to Zinc Sulfate in a 4 step, and what is the effect of that on cedar?

Simply trying to understand your argument.

And we are waiting Anxiously for Bruce to release his Cedar clewning program as I understand his does well on everything.

I can see you have done your home work. Some just don't get it. 

 

Unlike some who won't waiver from a position, I like to keep an open mind and experiment with ways to offer a better service. To each their own.

But that is the difference from those that will clean cedar and those that are cedar cleaners.

Also we don't stain or seal a cedar roof, just plan clean them. No need to stain them and sealing is a big no no, they have to breathe.

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What many don't take into account is the PH when dealing with wood cleaning. Given we are talking about cedar, most commonly redwood, cedar shakes roof cleaning. You'll find that many have cleaned one or two of them and often don't have the personal experience of trying the many different options available for cleaning cedar shakes. That's not to say they are cleaning them wrong, that is subjective, what I am saying is there are different applications that can be very effective at cleaning cedar shakes. One needs to remember there is a difference between the cleaning of and/or the restoration of cedar shakes. Many get that confused.

 

There is no one solution or chemical that is right for every job.  Knowledge of wood species, and chemical reactions are all factors in determining the best course of action for wood cleaning.  For wood cleaning its best to go with the rule of conservation which means using the mildest treatment that gives acceptable results.

  • Wood-cleaning-tips-160x1024.png 
  • Sodium Hydroxide - This chemical is primarily used to emulsify previous coatings of stain, dead wood and dirt.  You can use very diluted amounts to clean bare wood.  When you purchase a pre-formulated stripping solution,  surfactants, buffers and other misc. chemicals are added to work in synergy with NaOH.  Sodium Hydroxide is extremely caustic and will irritate eyes, skin and respiratory system.   Follow the manufacturers guidelines for personal protective equipment (PPE).  Pure Sodium Hydroxide(basic) ranges between 12 and 14 on the pH scale.  Application methods listed below.  To neutralize you can apply citric/oxalic acid and rinse.
  • Bleach - You can mix 4 gallons water, 1 gallon bleach (12.5%) and 1 cup TSP (Tri-Sodium Phosphate) for simple wood cleaning.  While a solution like this can be very effective at killing mold and prepping bare wood it has its pitfalls as well.  These include; browning of vegetation (TSP helps to reduce this), loss of natural wood color and respiratory distress.  Bleach’s counter part in wood cleaning, sodium per-carbonate, takes longer dwell times to achieve similar results but is easier to control application.  Because bleach (sodium hypochlorite) is reactive in nature it is more sensitive to dwell time, sun exposure, concentration and surface temp of wood.  So, while bleach may be an effective household chemical for wood cleaning, it takes a seasoned professional to know how and when to use it. Bleach by itself is basic with a pH around 12.6.  Application methods listed below.  To neutralize this mixture you want to thoroughly rinse with water.
  • Sodium Per-carbonate -  Advantages to sodium per-carbonate wood cleaners include; ease of use, emulsifies dirt, safe for vegetation, wood color retention and does not cause respiratory distress.  The emulsification of dirt allows for easier low pressure cleaning.  Disadvantages to sodium per-carbonate over household bleach is a slightly higher cost of materials and requires a longer dwell time to effectively kill mold.  In some extreme cases it may not be able to eradicate mold completely.  Sodium per-carbonate by itself is an Alkaline(basic) with a pH around 10.5.  Application instructions below.  To neutralize you can apply citric/oxalic acid based brighteners and rinse.
  • Citric Acid – Citric acid is used to neutralize a base or anything above a neutral PH of 7.  If wood is too basic prior to sealing, the new sealer’s curing process will be altered, resulting in premature failure.  If wood is too acidic, it may cause blotchiness and prevent proper penetration of your sealer.  Woods with a lot of yellow, red or brown in them including; redwood, cedar and red oak will tend to have a lot of tannic acid.  Tannic acid combined with iron rich water forms tannin stains.  Oxalic and citric acids reduce the iron compounds helping to suppress the formation of tannin staining.  In summary, acids such as citric or oxalic will brighten, neutralize and remove tannin stains from wood species containing tannic acid.  Application methods listed below.  Pure citric acid has a pH around 2.5.
  • Oxalic Acid – Oxalic acid is faster acting and more aggressive than citric but it’s also toxic.  Citric acid takes a longer time to brighten and achieve pH balance.  Oxalic acid and citric acid can be combined into a wood brightening/neutralizing solution.  A brightening mix with both citric and oxalic acid is how we typically neutralize after applying a base such as Sodium Hydroxide.  Oxalic acid works very well at removing rust stains in wood and concrete.  Oxalic acid by itself has a pH of 1.5.  Application methods listed below.

Definitions:
pH: A measurement of how basic or acidic a substance is.  A pH above 7 is considered basic while a pH lower than 7 is considered an acid.
Caustic: A substance that is corrosive to living tissue. Caustics refer to strong bases, particularly Alkalis.
Alkalis: A water soluble base. The adjective Alkaline is commonly referred to as a soluble base.
Base: A substance with a pH higher than 7. In wood restoration, Alkaline’s are used to emulsify dirt, dead wood, stain and mold.
Acid: A substance with a pH lower than 7. In wood cleaning, acids are brighteners and neutralizers.
Neutralization: A reaction between an acid and a base. Neutral is a 7 on the PH scale. Water is very close to a 7 on the pH scale.

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Interesting that you don't recommend sealing the roof. As a mold remediation company owner I can definitely understand the logic behind letting a roof breath since I deal regularly with the effects of roofs and attic spaces which do not breath.

But what about oiling? Is it because you are using a citrus base and Citrus is somewhat oily? Pretty much all the info I see out there says to oil after cleaning to re-hydrate the wood.  While I can definitely see the logic behind avoiding staining or sealing to allow the roof to breath, what is the logic behind not oiling...or is that integral to the process you use?

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Let's try this again.  From the OP:

 

If cleaning cedar shakes that have been stained, should SH be used?

 

The answer is no.  Period.  If anyone can find a way to remove stain (oil, acrylic or otherwise) with SH, please let me know.

 

For those that HAVE used SH on cedar (we have) you'll notice that it looks like crap about a month later.  If that's your bag, and your company's reputation is not important to you, then have at it.

 

Would you use SH on your own cedar roof?  Not me.  Cedar siding?  Heck no.  T-111 shed?  Nope.

 

I don't have a horse in this race - we hardly do cedar any longer and what others do is up to them.  The only reason I speak on  misnomers is to help the new folks that are just starting out.  And believe me, there are lots of misnomers out there.  (As busy as we are, I don't have the time nor desire for debates.)

 

Commentary - PWI is a great Pressure Washing website.  But I sure wouldn't take the 'consensus' on wood from there to heart.  Instead, reach out to the pros - those that restore cabins and specialize solely in wood.  Beth and Rod are the two foremost experts with a strong online presence that I know of.  Woodies.

 

Speaking of which, that same research will reveal about a 50/50 split among the experts on weather shakes should be sealed/oiled/etc.   To state absolutely, one way ore another, is yet another misnomer.

 

Now let me see - my $1400 teak outdoor set is looking a bit weathered  (I just took the pic for this post).  I think I'll go bleach it.  HA!  Hardly.

post-3-0-44179400-1406380566_thumb.jpg

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Let's try this again.  From the OP:

 

If cleaning cedar shakes that have been stained, should SH be used?

 

The answer is no.  Period.  If anyone can find a way to remove stain (oil, acrylic or otherwise) with SH, please let me know.

 

For those that HAVE used SH on cedar (we have) you'll notice that it looks like crap about a month later.  If that's your bag, and your company's reputation is not important to you, then have at it.

 

Would you use SH on your own cedar roof?  Not me.  Cedar siding?  Heck no.  T-111 shed?  Nope.

 

I don't have a horse in this race - we hardly do cedar any longer and what others do is up to them.  The only reason I speak on  misnomers is to help the new folks that are just starting out.  And believe me, there are lots of misnomers out there.  (As busy as we are, I don't have the time nor desire for debates.)

 

Commentary - PWI is a great Pressure Washing website.  But I sure wouldn't take the 'consensus' on wood from there to heart.  Instead, reach out to the pros - those that restore cabins and specialize solely in wood.  Beth and Rod are the two foremost experts with a strong online presence that I know of.  Woodies.

 

Speaking of which, that same research will reveal about a 50/50 split among the experts on weather shakes should be sealed/oiled/etc.   To state absolutely, one way ore another, is yet another misnomer.

 

Now let me see - my $1400 teak outdoor set is looking a bit weathered  (I just took the pic for this post).  I think I'll go bleach it.  HA!  Hardly.

Ted. You say you don't have a horse in this but you keep kicking it! Let's just agree to disagree and move on? I don't think anyone is telling any one what to do. They are just saying research and experiment. Personally I learn new things all the time and have an open mind enough to experiment and try new things. To me expert is a subjective word. I like to us the word opinion. So whatever I say on this forum or any forum is nothing more than my opinion from my research and personal experience. Please don't take it personal, I don't.

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Ted. You say you don't have a horse in this but you keep kicking it! Let's just agree to disagree and move on? I don't think anyone is telling any one what to do. They are just saying research and experiment. Personally I learn new things all the time and have an open mind enough to experiment and try new things. To me expert is a subjective word. I like to us the word opinion. So whatever I say on this forum or any forum is nothing more than my opinion from my research and personal experience. Please don't take it personal, I don't.

 

Nothin' personal on my end.  Do what you want.  Yet when I see misinformation purported as fact on our forums, I'll speak out if  and when my time allows.  I do so for others who are where I was years ago (just starting out), not so much for myself.  I run the business the same way, based on facts.  I'd say it's workin' pretty darned good  :-)

 

OP Kelly - give me a call some day.  I'll gladly talk through some of this with you in detail.  We have a small operation in the Atlanta area and can lock arms on some things if you'd like.

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