Using Bleach to clean a PT deck

[seymore 90]

Here is a section of a 1200 sqft deck we cleaned today.The bleach mixture was light and cleaned up pretty easy 3hrs start to finish.

We are gong to stain it early Fri. before it gets to damm HOT. :cool:

[JFife 14]

I was thinking percarb was around a 10pH. I don't think it is NECESSARY to put acid on percarb'd wood, but it does brighten it and thus causes the final stain color to be more vibrant.

[Beth n Rod 1,279]

Percarbs are slightly alkaline. Wood is slightly acidic by nature. You need to neutralize. Granted, you may make up a weaker solution to neutralize with, but it's a step we never, ever, skip.

We also perfer (have for years) Citralic acid to pure Oxylic. Citralic is a blend of Oxylic an Citric. Extreme Solutions makes it and sells it, Sun Brite sells it also. It goes on easily, doesn't leave the wood with an unnatural silver hue like you can get if you over apply Oxylic and it dries, looks more natural, and it is less hazardous to work with than pure Oxylic. Pure Oxylic exposure can lead to sterility. To some of you that may matter. Nuff said 'bout that.

Beth

[PressurePros 249]

Oil/Alkyd sealers also penetrate more effectively into a wood enviroment that runs slightly acidic.

[Beth n Rod 1,279]

Thank you...!

Beth

[Celeste 341]

There was a thread somewhere that said that brightening was a "side effect" of neutralizing but a very smart chemist once told me that neutralization was the side effect of the brightening process. He said that in order for the stain to perform EVENLY, the wood should be brightened. (Keep in mind we were speaking of the step after a percarb cleaning - there is no option after a strip :))

Celeste

[Beth n Rod 1,279]

Smart man Shane. That was an expensive sounding deck!

Philip,

Brightening the wood also helps to remove the tannin stains around screws and nails in the wood making it look more like it did when it was first built. Neutralizing stops the action of any akaline product used to wash with as well creating basic salts.

Also remember, the products are only active when wet. Once you rinse the product off the deck thoroughly, it dries and the effects stop there. The wood will return to its natural pH.

Yes Celeste, there is a so-called side effect and it happens in the use of many chems we apply to wood to get it to do what we need it to in order to prepare the surface for the sealer.

Neutralizing is the action of stopping the reaction of the previous product used, Brightening is (side effect as it was mentioned) the other action of bleaching out the excess tannins on the surface leaving the wood lighter in color. Another side effect is the way it helps to disolve rust on nail and screw heads if it is applied strong enough although this is only necessary if you have stripped the deck.

Rod~

[James 625]

Using bleach with penitrating oils Like ready seal has no effect on future usage. I have decks I use bleach every year on . They look Great !!

[Dale 16]

What IS the "cumulative damage" that shows up? How can I identify it. How many have personally seen this damage and how did you arrive at the conclusion the damage was from bleach/soap use? Like anything else theres "use" and "misuse"...

When working with products that only have a 12 - 18 month life when using the "right" products....how much shorter a life can one expect?.....let me add, I'm not a bleach user very much, but am starting to rethink my reflexive grabbing of the percarb and defelting pads for almost EVERY project. On jobs that have a uniform finish and only need light cleaning and no stripping before applying another coat, I'm heading for bleach/soap if I can get the concentrations to work for me....this is the way I'm thinking about it...if I use a percarb, its gonna strip some finish and go all runny on me in certain areas and I might as well strip the whole thing ( I'm thinking house siding here)..if use a weak enough solution to not strip the stain...it won't effectively deal with the mildew...if I use a bleach/soap solution in the right concentrations, I can effectively clean the surface dirt and deal with the mildew without the finish "gettin' all runny on me" and necessitating more work..more expense..and a greater exposure to problems caused by more washing/rinsing of lap siding/logs..water directed at vented soffits..etc. I say this because I think its human nature to strive for a visually even finish when working and if the finish starts to strip there may be a tendancy to over wash/rinsing, throwing more water around than whats actually needed. Maybe I'm overstating this a bit, but theres something to be said for simplicity if the results are equal.

[Beth n Rod 1,279]

This convinced me of the effects of bleach on wood and the problems it poses to the sealer applied afterwards.

To state an example: A number of years ago, I washed a house after washing the deck (client add-on after the job began) and got plenty of the cleaning solution (1/3 gal bleach and other cleaning ingredients in a 5 gal bucket and x-jetted onto the siding) on the deck within a few feet of the siding. Even though I thoroughly rinsed the deck off afterwards, the end result was that the sealer did not take well in that area and needed to be recoated in order to even it up.

I had side by side evidence here. In the areas of exposure, the sealer didnt take well vs the areas where the wood had not been exposed to the house wash solution, the sealer held up well and looked as it should after a fresh application.

In trying to be fair to both sides of the preference in this topic, here is a revelation Beth and I had ... bleach users have no way to see the effects since they apply it totally over the deck leaving no part for comparison. It may explain why others dont see a problem with bleach use.

I dont care for the effects of bleach on wood. After actually walking on so many decks for estimating, washing, sealing, and talking to the clients about the previous companies process' in order to understand what the deck has been exposed to...it becomes a learned tell tale sign of what has lead to the sealers failure.

Things like: Bleach use, poor wash methods (water only, etc...), failing to neutralize, not back brushing/padding/rolling, over/under application, High moisture content/low ground clearance, sanding with 100+ grit, incomplete strip (products still present on wood), Sappy and deciduous trees in proximity to the deck, homeowner neglect to keep the surface free of debris/spills/pet excrement/urine/vomit, and the list goes on but I think that gives an example of a trained eye.

Im not trying to promote one thing over another or talk anyone out of using any of the methods mentioned in this thread, but giving an example from my experience as a point for others to consider.

Rod~

[PLD 14]

Pure Oxylic exposure can lead to sterility. To some of you that may matter.

It certainly does. I consider it a benefit! :)

[PLD 14]

I had side by side evidence here. In the areas of exposure, the sealer didnt take well vs the areas where the wood had not been exposed to the house wash solution, the sealer held up well and looked as it should after a fresh application.

Did you neutralize that spot? If not, the high PH and emulsifiers present in that location would have helped degrade the stain and affected it's results. That would be a plausible explanation for your results.

[PLD 14]

Im not trying to promote one thing over another or talk anyone out of using any of the methods mentioned in this thread, but giving an example from my experience as a point for others to consider.

Neither am I. And I certainly don't have nearly the experience with staining/sealing that you do. Hence, my comments are from a chemistry background, and not from a "Woodie" background. Anyway, my original point was that what we call neutralizing is actually lowering the Ph below neutral.

As for the the wood returning to neutral after time, that will happen but not in the time frames we work in. Keeping the surface wet and rinsing certainly assists in the process by diluting the acids, but drying would do very little. In the absence of water, acids form soluble salts that would adhere to the wood fibers and remain until they decomposed, recombined, or were flushed away by huge amounts of water over long periods of time.

[Beth n Rod 1,279]

Better to have wood be slightly acidic, than alkaline. Sealers don't like alkaline surfaces, but since wood can be acidic, they are formulated for that.

Beth

[Beth n Rod 1,279]

Did you neutralize that spot? If not, the high PH and emulsifiers present in that location would have helped degrade the stain and affected it's results. That would be a plausible explanation for your results.

Exactly! No I didnt, but it also proves that bleach effects the end result. Bleach users dont mention that they neutralize afterwards, so whats to keep the residue from reactivating after a rain or morning dew?

Again, I prefer not to use bleach on wood.

As for the the wood returning to neutral after time, that will happen but not in the time frames we work in. Keeping the surface wet and rinsing certainly assists in the process by diluting the acids, but drying would do very little. In the absence of water, acids form soluble salts that would adhere to the wood fibers and remain until they decomposed, recombined, or were flushed away by huge amounts of water over long periods of time.

Understood, one method is to make sure the wood is damp before applying the acid to keep it working on the surface area. This helps to make rinsing more effective and reduce the possibility of acids residing in the wood fibers for future reactivation.

Dale, the wood will be very pale from the last exposure to bleach, the ends of the boards dry,crack and split early in its life, cracking, feathering/scaling and splinters amid the boards in newer construction (5 years or less) are signs of bleach use.

Horizontal surfaces fail much quicker after bleach use and the verticals end up looking pale yellow (if a clear was applied) otherwise, tinted sealers will turn darker than they were intended because of bleach residue in the wood.

Rod~

[tropical wave 22]

I went into my local Sherwin Williams dealer today for some for a customer unrelated to wood care, but I wandered into the "professional contractors" area and looked at some stuff.....as Ive heard by quite a few people, Deckscapes isnt all that bad although Ive never used it, anyway, I look at all 3 of their Deckscape line of prep chemicals...... very expensive by the way...

Deckscapes Stripper-----$18.99 gallon-----contains sodium hydroxide

Deckscapes Brightner----$14.99 gallon-----contains oxalic acid

Deckscapes Deck Wash--$12.99 gallon----heres the kicker, sodium hypochlorite, bleach, and sodium chloride, common salt....??

why do all these sealer companies keep using chlorine bleach to kill mildew if it really is bad for the wood? I mean they've been around for a long, long time and I would imagine have tested stuff for years....why wouldnt they just sell percarbs in a much lower concentration if it would be better for the wood and make their product last longer??

just wondering......Im straddling the fence still on this one.

[PLD 14]

Exactly! No I didnt, but it also proves that bleach effects the end result. Bleach users dont mention that they neutralize afterwards, so whats to keep the residue from reactivating after a rain or morning dew?

I misunderstood the first time you said it. Yes, bleach and emulsifiers will affect stain performance by begining the decomposition while it is still in liquid form. You must neutralize when using a high Ph cleaner.

BTW, Oxalic acid exposure can lead to sterility and kidney damage whether or not it is mixed with citric acid. For purposes of selecting PPE, please treat citralic as you would Oxalic and Citric seperately.

[Beth n Rod 1,279]

why do all these sealer companies keep using chlorine bleach to kill mildew if it really is bad for the wood?

Manufacturers of cleaners containing bleach do not specify the best circumstances for using bleach. They only specify what it is for. I suspect that label space limitations and the questions it would provoke are another reason for not describing proper use. Using on a deck that has been properly sealed (film formed to protect from any penetration into the wood itself) to control mildew is a good one. But for our clients who want to keep the deck looking good in between services, we recommend oxyclean as an alternative since it is a percarbonate which has a short life and exhausts itself in a few hours leaving it relatively harmless to humans and pets. Bleach on the other hand, if not thoroughly rinsed can be reactivated by moisture from rain or dew and create an exposure situation or even a slip/fall hazard as it leaves surfaces quite slippery.

I mean they've been around for a long, long time and I would imagine have tested stuff for years....why wouldnt they just sell percarbs in a much lower concentration if it would be better for the wood and make their product last longer??

Assumption is the biggest mistake we all make at one time or another. Many people proceed on the assumption that because it is on the shelf ready to be bought, it must be ok otherwise it would not be there. Also, this equates to trusting the product to do what its labeling specifies without harm or damage. There are cautions listed but those mostly pertain to the human element (the part that they can be easily sued for) and have little to do with the effects it may or may not have on certain surfaces. Buyer beware. I have learned to investigate as you do now and not take anything at face value when it comes to buying a product. Some may call me a skeptic, I call it experience and learning how to avoid being taken advantage of.

BTW, Oxalic acid exposure can lead to sterility and kidney damage whether or not it is mixed with citric acid. For purposes of selecting PPE, please treat citralic as you would Oxalic and Citric seperately.

This is good advice for all who read it. I did a great deal of research on the different products and in my travels, found many different sources for information on the problems associated with oxalic acid and exposure...Nitrile gloves are my preference.

Rod~

[James 625]

Rod can you please clarify your information on bleach being reactivated. This is news to me.

I did try to stay out of these bleach issues. As someone who uses both when deemed necessary. On a surface that has a film bleach works better and faster than Oxiclean . Just tell them to rinse twice.

[tropical wave 22]

Rod, excellent post and Im sure that I assume nothing, there is all kinds of crap being sold in all areas of merchandise......Im just shocked that sealer companies are promoting their own bleach products to go along with their sealers....

not that I really give a crap, Im not using any of these products, but to get called after a real hack job by homeowners buying into advertising junk, just thinking too much I guess.... :cool: have a great weekend

[Beth n Rod 1,279]

Jim,

I am referring to residue left behind if not thoroughly rinsed. Many know that the chlorine can be burned out by the sun after a certain amount of exposure, but we all know that there are many homes we service that have extensive tree coverage and dont get much sun.

I have also heard of homeowners who tell the tales of minor chemical burns after their deck was washed with bleach and wasn't rinsed well. I wont rule anything out as being possible.

Bleach does work faster and easier than oxyclean, but many homeowners arent that adept to the details we are as experienced professionals, so, keeping that in mind, I take the caution route and suggest the lesser of the two.

Buyer beware, user take care.

Mike,

You betcha! :)

Rod~