Roof work: chemicals and methods

[RyanH 14]

Does anyone here have much experience with cleaning roofs? I clean some houses in areas with some pretty steep pitches on the roofs, usually 2, 3, and 4 stories high. I have had a few requests to remove the black streaks (sometimes the entire roof is black on the north side) from the roof. The height is too great for an extension and a pitch-witch, and the pitch is too great to simply walk around (generally greater than 45 degrees....sometimes around 55-60). SO, I went to a local outdoor adventure store and spent some big bucks on mountain rappelling equipment, got some instruction on how to use it, and am ready to (safely) tackle the high jobs.

Now, my BIG questions. I am concerned about "pressure washing" a roof because I don't want to take off any of the grit. Thus far, I have kept the tip fairly high from the surface, so the roof is not being hit with high pressure, and I am having great success with this and have not noticed any damage to the shingles. However, I am sure that I will have questions from time to time from concerned customers.

Also, what type of chemicals do any of you guys (gals) use? I have checked out the roof cleaners around here and they all seem to use sodium hypochlorite and/or sodium hydroxide, the same stuff in regular bleach. Will these chemicals void a roof warranty, or are there others that are better to use?

I am asking these questions specifically because I think that roof cleaning can be a huge business in my area....most of the "lowballers" and part-timers only want to clean the side of a house and a driveway. Nobody seems to want to do the dangerous stuff, which tells me that there is great demand and little supply ( equals BIG $$$!!!). I would like to start advertising an exclusive roof cleaning service, but I want to make sure that the chemicals and methods I use are non-destructive so I can be confident in my advertisement and marketing.

I would appreciate any help, advice, information, or tips from anybody out there with some knowledge and experience in roof work. Many thanks!!

Ryan H.

[Paul B. 523]

Ryan,

Sodium Hypochlorite is one of the few cleaning solutions approved by the roof shingle manufacturers.

Liquid Pool Shock mixed with water works very well.

10%-12% concentrate diluted to 3-4% or 1:3 ratio will do the job.

No heavy rinsing is required. If want, you can go without rinsing it.

If you add anything else, such as Sodium Hydroxide, or TSP, (as some folks do) you should rinse.

If you understand the chemistry of shingles, you know that asphalt is an oil base product. Sodium Hydroxide is a degreaser which will remove these oils and help the deterioration process.

Hard to quantify how fast the deterioration is.

Walking on a roof also harms the shingles. We use an X-jet to apply, taking care to keep pressure off shingles and to control overspray.

[Earl 14]

Sodium Hypoclorite is what I use. I have only done a few ( have repell equip. as well). I mix a 50/50 solution and add some Tide (cap full just to help it cling). I have a 5 gal air pressurized sprayer with 50' of hose that works Ok but a sureflo pump and 200' hose would be ideal. I hope to put together one this winter.

I spray it on and most of the time lightly rinse. Also x-jet with 3/8 hose works on calm days and useually have to apply 2 or 3 times to get the job done. Do a search on Gloeocapsa Magma (Black streaks.) I found some good info that I printed to inform customers. Also Asphalt Shingle Manufactures Ass. Earl

[Mike Williamson 198]

I guess I'm lucky to be in Florida! We have very very few roofs with pitches that can't be walked without safety equipment, I assume due to the fact that snow building up on the roof is not a concern. Another plus to this is that you get a heavy buildup up leaves and pinestraw on the roofs, giving a bigger incentive to homeowners to have it removed!

[Guest rfitz]

Ryan, what about a chicken hook on a ladder, ? that is what I see most guys using who do roofs,? I will be trying one of these this year since I want to get into more roof and shake cleaning, I was also thinking about renting a lift, they are relatively cheap, $300 a day, and 2 guys can manually pull it around house and pull the legs out and support it, and up you go, I think I will charge $3.00 a sq ft for cedar shake roofs plus the cost of the lift, if I get more into cedar shake cleaning, it is very specialized and few companies do it here, they just dont have the equipment for it...

[travlinjohn 14]

50 % of our business is roof cleaning because we find it most profitable. We use sodium hydroxide exclusively. In the past seven years we have cleaned a number of roofs twice (repeat business) and have not found any noticable deterioation of the shingles. Although we have used both chemicals we've stayed with sodium hydroxide because it cleans the roof better, chlorine seems to leave streaks. We can always tell when a roof has been cleaned with chlorine. We also found that sodium hydroxide is not as damaging to plants as chlorine. One note: DO NOT USE SODIUM HYDROXIDE ON WOOD SHINGLES. As for equipment and cleaning methods we use I invite you to visit our web site at ***************** and click on **********home of the ************

Travlinjohn

[Beth n Rod 1,279]

John -

What is the % of SH you are using on the roof? I ask this because using too much of it will degrade the shingle. Sodium hydroxide is the most caustic thing there is. It will degrade petroleum based products, and asphalt shingles qualify as that.

Any time you alter pH it is necessary to restore the balance of the pH, especially if you are working on a surface that can deteriorate from exposure. Do you neutralize after cleaning a roof with SH? If so with what?

You state that you can do more damage to plants with chlorine than SH.... SH is far worse.

SH is far better for WOOD at the right dilution than chlorine is. However ideally a percarb would be best on a wood shingle.

Now regarding your advertising here, we are not a distributor for your products and our rules state that only those vendors whose products we represent may advertise her. This includes contacting people through the BBS. We welcome you to post and become a part of the community here, but please go back and read the rules. Thank you.

Beth & Rod

Administrators.

[James 624]

Beth were do you get this information that SH is better than Bleach on wood ? I have never seen this information and I use bleach all the time.

[Guest rfitz]

I would have to disagree with statement sodium hydroxide is better for wood than chlorine... Although both can and will damage the wood surface, I would for sure say that sodium hydroxide would do far greater damage on wood than chlorine, shlorine is meant to clean the wood surface whereas SH will eat right through any finish, then start eating the wood if not neutralized

[Everett Abrams 501]

Power-washing deck not a good idea.

My neighbor is ready to clean this wood deck. He's also about to make a common mistake. "Time for the power washer," he says. "That'll get it good and clean."

Contrary to popular opinion, cleaning with a high-pressure power washer is probably one of the worst maintenance practices for a wood deck.

"A lot of people use power washers or scrub with chlorine bleach," says Tony Bonura, eastern area manager for the Western Red Cedar Lumber Association. "They don't understand that high-pressure washing and chlorine bleach can destroy the fibers in the wood."

There's a better way to keep wood decks clean and make them last longer, says Bonura, who, with more than 30 years in the wood business, should know a thing or two. He's ready to share some tips - such as how to clean and what kind of finishes to use - and credits the Forest Products Laboratory in Madison, Wis. for providing him a wealth of information over the years.

"It's our government dollars at work," he says. The Forest Products Laboratory does not advise against using a power washer or chlorine bleach on a wood deck, and it notes that many contractors use the technique and some type of chlorine bleach. But in both cases, wood can be harmed rather easily.

The Forest Products Laboratory, the public's leading wood research institute, was established in 1910 by the U.S. Department of Agriculture Forest Service. In cooperation with many universities, industries and federal and state agencies, the Forest Products Laboratory has more than 250 scientists and support staff for research in virtually every type of wood use, from pulp to paper to preservation.

It is wood preservation that interests Bonura the most, and in decks, one of the first steps is regular cleaning to remove dirt and mildew.

"First, the best way to clean most wood decks is with an oxygen bleach," Bonura says. Several oxygen bleach deck cleaners are available through home centers and hardware stores. Bonura says to check the labels and look for products that contain the highest percentage of sodium percarbonate (when this powder is mixed with water, it becomes oxygen bleach).

Follow manufacturer's directions, Bonura says. For oxygen bleach products, that means mixing with water and applying with a soft, spongelike applicator or a pump sprayer. "Scrubbing with nylon brushes can also damage wood fibers," Bonura says. Usually, oxygen bleach should be on for 10 minutes, then rinsed thoroughly.

Bonura says oxygen bleach cleaners are best for removing dirt and mold but will not remove stains made by iron and tannin (more common in cedar and redwood decks). For these stains, black in color, use a cleaner with oxalic acid. "Iron stains can look like mold," Bonura says. "So I tell people if you clean with oxygen bleach, and it doesn't come out, it's probably an iron or tannin stain."

Bonura also advises great caution when using cleaners containing oxalic acid, which can be purchased at hardware stores and auto parts stores. Oxalic acid-based cleaners are highly toxic and should not be mixed with other ingredients. Again, Bonura says to follow the directions on the label.

Once the deck is clean, use a preservative that protects the wood from dirt, water and sunlight. There are four common types of deck finishes - clear, tinted, semitransparent and opaque. Bonura recommends a penetrating oil-base stain that is formulated for deck use. The stain should also repel water and protect from harmful ultraviolet rays. "Make sure it is made for the decks," Bonura says. "This way it stands up to traffic."

According to research by the Forest Products Laboratory, semitransparent stains penetrate wood without forming a continuous layer. That means there won't be a buildup to chip, peel or crack. In addition, the pigment in the stain protects the wood surface from sunlight.

How often should you clean and finish your wood deck? That depends on several factors, Bonura says, including traffic, exposure to sunlight and moisture and the type of wood.

This article was published in the Atlanta Journal of Constitution on 08/14/2003. The author was Gary Dymski / Newsday.

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[James 624]

In every book and I have them all the forest labs say's use bleach !! Even the Finish Line article you sent me said clean with bleach. It points out in some article's which kind of cleaners their are .

This is for the do it your selfer type article. I tell people to use wolman products if there doing the job them self.

This is also the type of info that will confuse the consumer. 3 year old cedar deck!! I'm not using a pressure washer I put down the cleaner(pre-carb) I rinsed the deck ? (hose) It still looks like crap? I use brightner looks better ? I use an opaque stain ( peels in 6 months) ? What happened ?

Good question for advanced woodcare !!

[Guest rfitz]

For what its worth, I did a job this past summer, it was a fence going down both sides of the yard, I did the right side with sodium percarb. and then britener, then I did left side with Soap, and chlorine then britened, and to my surprise, the soap and chlorine fence looked much better..? anyway, Before I strip any deck, I always use soap and chlorine to wash first, then a mild stripper, and mild britener, I hardly ever get decks that just need cleaning and re-staining, usually the customer has tried for years to make his deck look great, like a brochure deck. often trying different products every year or every other year, then when they call me, it looks horrible, when I tell them I can make it look like the deck in the brochure, and then they see my portfolio

of before and after pics, they cant believe you can bring a deck back to look awesome again, But remember, a customer wants to hear how much care you will put into his deck when restoring it, and you will do his as you would do your own, and if sold right right, competetion doesnt have a chance at getting that job, even at half your price, the presentaion, referrals, and portfolios will land you more jobs than you can handle, I usually tell my customer, the biggest difference between me and the other guy is, I will actually show up...

[Rick G 14]

Back to the topic at hand. Look at these links. Then explain to me why you would use something other than what the manufactures recommend to clean their own products? They make them, they say use this method to clean them, seems like a no brainer to me. But there seems to be a large number of people who go their own way and I can’t figure it out? What do you know that these people don’t?

http://www.asphaltroofing.org/questions_tech.html

http://www.ntrma.org/news4.htm

[RAC 14]

Rick:

Good points, but keep in mind that the roof materials manufacturers ' main concern is making and selling roof materials. They recommend chlorine because that's how it's always been done and they know it works.

Very few of the manufacturers invest a whole lot of research and development $ in how to clean their products in a safer manner. Some shingle manufacturers have done it only because of warranty claims arising from their fillers that actually promote algae growth - so now they have come up with AR shingles - but the tile manufacturers, in general, don't seem to care at all.

I have worked with extensively with several of these manufacturers and they all know that there are better ways than chlorine, but it's not a front-burner issue for them. If you look at the tech bulletins, you'll see that they are 9 years old - and they are exactly the same as the ones published in 1980 (with the exception of the sentence regarding algae resistant products). There's not much recent R&D going on there.

A good example: I had one of these guys acknowledge that safer chemical cleaning is better for the shingles and will help extend the life of the shingle. Then he asked me to explain how this was going to help him sell more shingles.

Also:

I you call a few of the shingle manufacturers and ask them for an alternative to chlorine, most of them will tell you that Home Depot has products that will clean the shingles safely. These are generally sodium hydroxide based products.

Sodium Hydroxide is actually a very common cleaner found in everything from oven cleaners to toothpaste. The levels of caustic are really what determines whether it will clean without doing damage. A 1-2% level of Sodium Hydroxide in your finished mix will clean the roof effectively and will not damage the roof if rinsed of properly. Chances are, you'll do much more damage to the shingle by rinsing than you will by using the sodium hydroxide on it.

Hope this helps!

[Guest rfitz]

If Sodium Hydroxide based products are used on roofs of all kinds, then you would assume after washing, you would need to neutarlize the SH with Oxalic Acid, then rinse all chems off, ? is the way most do it..??

[Paul B. 523]

On asphalt and tile roofs, it is not necessary to neutralize with an acid as long as you are not adding a coating after washing.

Water will neutralize it, and rain will remove any residue that may be left behind.

When you are working with wood, you are in most cases adding a coating after cleaning so neutralizing is more critical. Also, the oxalic / citric acids will brighten the wood that the sodium hydroxide darkened.

[Paul B. 523]

These are some alternate asphalt roof cleaning chemicals to Sodium Hydroxide and Sodium Hypochlorite.

Zinc sulfate (monohydrate).

Zinc chloride.

Copper sulfate (also called blue stone)

Potassium salts of fatty acids.

ZINC AND COPPER STRIPS (copper being more effective than zinc).

[RyanH 14]

Chemically, you cannot have sodium hypochlorite solution without having some sodium hydroxide. Dissolving sodium hypochlorite in water will make a solution containing some basic components (hydroxide). There is an equilibrium between the available hydroxides and hypochlorites; I'm not sure what that equilibrium ratio is (it is temperature dependent, though), but I know that you will definitely be using a basic solution if you use the hypochlorite. The solution is not strong enough to warrant neutralization, however. A good rinse with water will dilute the solution enough so as to be inert. The thing to worry about would be allowing too much of the solution to dry on the roof, leaving the white sodium hypochlorite salt behind. Customers might not be too happy about this (until a good rain rinses it for you).

Sorry if I sound a little incoheherent. I'm having a hard tpying and its 50-something degrees in my office, so the fingers aren't working very well!

Ryan H.

[Paul B. 523]

Ryan,

You are correct about a very small amount of Sodium Hyroxide being present in Sodium Hypochlorite (NaClO). Sodium hypochlorite is manufactured by mixing chlorine with sodium hydroxide and water.

Bleach cycle starts with salt water, which is broken down by electric current into sodium hydroxide, hydrogen and chlorine.

The sodium hydroxide is mixed with water. Next, chlorine is added to form sodium hypochlorite, the active ingredient in liquid bleach.

I believe a 12% concentration of Sodium Hypochlorite contains less than 0.25% Sodium Hydroxide. Sodium Hypochlorite diluted to about 4% concentration, would then contain less than .084% Sodium Hydroxide. Much less than if a 10% Sodium Hydroxide based solution was diluted 1:25 (0.4%).

I believe some of the folks sell 20% concentration of Sodium Hydroxide for roof cleaning and the dilutio ratios at 1:50 would than give you 10 times the amount contained in Sodium Hypochlorite.