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Pressure Washing Shingle Roofs ?

Roof Cleaning West Chester PA · Premium Member Roof Cleaning Institute of America

Apple Roof Cleaning Tampa FL (813) 655-8777 wrote:

There has been some debate recently about IF it really is harmful to pressure wash roofs made from shingles. Both the ARMA and the Canadian ARMA warn against high pressure, but the question remains HOW much pressure does it really take to harm a shingle roof ?
This question reared it's head during a recent discussion on Certification. We do not wish to alienate our friends at PWNA who pressure wash roofs. However, we are the RCIA, and like to think we set the standards for roof cleaning. W/o giving my feelings on this subject, how do YOU feel, as an RCIA Member ?

HOW much pressure? I really don't know if you can put a number on it. There are a lot of variables involved so it's difficult to say. As far as our friends at PWNA, they have every right to go about business and make a living however they see fit. I'm not here to judge anybody no matter what kind of method they use. I wouldn't use a pressure washer, but that's just me.

The reason I joined the RCIA is because I feel it's the gold standard for roof cleaning. I'm sure when the certification process is revealed, it will offend and alienate some people. It's just my opinion, but alienating the PWNA shouldn't even be a concern (unless there's legal information that I'm not privy to). They don't have to slap the RCIA logo on their business card, but if they do, it should be because they've adapted our way of cleaning roofs. If they still want to pressure wash, that's there business, they just won't be doing it the RCIA way.

Nobody said our way is the only way, we just feel that it's the best way ... nothing wrong or offensive about that.

Watsonwindowwashing · Guest

I think that a pressure washer at a 15 degree angle will start to harm the shingles at about 2 inches from the surface. As we all know, the pressure applied to a surface diminishes as the distance increases. Therefore I would say 2 inches or less would damage the shingle at 3000psi.

Watson-Window-Washing.com
951.581.6608

WWash.com
WindowcleaningCA.com

Roof Cleaning Bradenton FL 941-822-2454 · Guest

I am good with no pressure, period. I have become an advocate for the system designed by the years of Chris T. experience. If it isn't broke why try to fix it. I'm good.
Kim R

Guest

I'm with Kim...lol

Matthew · Guest

I can tell you from personal experience that granular loss can happen as low as 200-300 psi.
So, I'm not sure how people think they can use a pressure washer on shingles.

Now before somebody gets there panties in a wad, yes I know that you can use a 4030 tip on a 4000 psi machine and get away with.

But I think the important variable in this question is why are you using pressure in the first place?
Is it because the sodium hydroxide based roof cleaner doesn't come off without it?

Because we all here at the RCIA know that our soulutions clean all by them selfs and a simple rain can rinse it off.

My personal opinion is 100 psi max for shingles. 1000 psi max for Tile.
Since I know I can clean them both with between 45 and 60 psi... that's what I do.

Central Iowa Roof Cleaning · Certified Cedar Shake Roof Cleaning Specialist

Non pressure or no pressure means just that. Personally I don't own a pressure washer. That's not to say pressure washing doesn't have it's place, just don't think it is designed for roof cleaning.

There is a picture on my web site of a tile job started with a pressure washer and they called me to take the job over.

I am not saying you cannot clean a roof with a pressure washer, but I know of three roofs in Des Moines that are being replaced as a result of someone using a pressure washer. I know because they called me to see if I could correct the issue, which I couldn't.

Why even have the debate. Everyone knows soft wash, non pressure or no pressure is effective. This is RCIA and I joined because of the effective process which is non pressure or no pressure. My customer are very happy with the process I use, non pressure!

What did Kim say, " if it's not broke why fix it."

Guest

I'm thinking Mythbusters?? Let's have Jamie and Adam settle this! smile

RCIA Founder

RCIA would like to be friends with other Industry Org's. In fact I have went out of my way to make sub forums for just about every industry org. I see thousands of pressure washers trying to learn the no pressure way of cleaning. I can't recall ever seeing a non pressure roof cleaner abandoning it for pressure washing.
However, it was pointed out to me by a good friend who's opinion I respect very much that we have no actual proof that pressure washing causes damage. In other words, we have no outright statement from shingle manufacturers that X amount of Pressure causes damage.
Now, they do warn that high pressure must NOT be used, but how high is high pressure ?
A very interesting point ....
Thoughts ????

Guest

ARMA - "Caution! High pressure washing systems for algae removal should not be used"

Good Enough for me.

Central Iowa Roof Cleaning · Certified Cedar Shake Roof Cleaning Specialist

Apple Roof Cleaning Tampa FL (813) 655-8777 wrote:

I see thousands of pressure washers trying to learn the no pressure way of cleaning.

Thoughts ????

Chris:

Is this why the question has come up. Pressure washers wanting to be roof cleaners with their present equipment?

Anyway, I guess at present no one can make a case for or against until high pressure is defined i.e. 100, 200, 300, 400, 500, 1,000 psi.

All I can say is all I have is a 12V pump with up to 60 psi, which we all know is not off the tip.

The best solution is don't use equipment for roof cleaning that can generate high pressure and the issue would be a moot point.

I know this doesn't answer the question, but it is a solution. LOL

Guest

Roof Cleaning Northern Virginia (571) 250 9650 wrote:

I'm thinking Mythbusters?? Let's have Jamie and Adam settle this!

Awesome Ted!!!

Roof Cleaning Cleveland (216) 323-0552 · Mar 4, 2011

I completely agree, we are the no pressure roof cleaning forum. I don't think we should change our way of doing things to make freinds with the PWNA.

Matthew · Guest

No proof!

Come ride with me for the day.

I can show you each and every roof in Sun City Center that has been pressure washed and the evidence of why it's bad.

The problem isn't the one Pressure cleaning company with a 3800 psi 6gpm maching using a 4030 tip.
The problem is the 4 million guys using a 4 gpm 4000 psi machine with the nozzles it came with.

Roof Cleaning Bradenton FL 941-822-2454 · Guest

More questions to consider besides the PSI factor about this other method is what are the benefits?
Will the job be done more efficient?
Will the HO be satisfied with the results?
Will there be increased risks taken for the contractor and or HO?
What is the cleaned roof longevity of the pressure cleaning v non pressure?
How different are the applied chems?
Is there a rinse factor for the PW method for landscaping? (determined by the chem used)

I just went and pressure washed some shingles and the zero tip killed it obviously, but the 25 degree @ 2inches some granule loss, the sample was a 10yr IKO.
with a 4k PSI pw.
I am not to much into the mechanics but there is my 2 cts.
Kim R

Matthew · Guest

Here's my major point.

A pw doesn't kill the algae.
No pump does... it's the solution.
So what solution are you using?
Our solution works without pressure.

So why the discussion?

The discussion is because companies can't sell our solution in a bucket and make money.
What they can sell... HAS TO BE REMOVED WITH PRESSURE.

This is about shingles of course.

But even with tile. Pressure doesn't kill algae, bacteria, or mold.

Here are some pictures to show what a pw can do.
My roof pump couldn't do this much damage if I disconnected it , climbed up on the roof and threw it at the shingles.

-- Edited by Matthew on Friday 4th of March 2011 08:44:59 PM

-- Edited by Matthew on Friday 4th of March 2011 08:45:24 PM

gutterdog · Mar 4, 2011

With moss on the roof, and nothing but a garden hose last year. Well water too. Low GPM. What is a garden hose? 65 85 psi? They wanted the moss gone that day. It pulled patches of granules out. I told them! Another customer in a hurry, last year took a leaf blower up there. After us. Heard the same thing.

Now diff than all the above. That roof in Calvert, our first for the year. I seen one piece of moss move whe sprayed with pump up? I picked it up with no problem??? Other moss wasnt the same. Half that moss I picked up and threw off the roof. lol! A lot of granule loss already. From the lichens. Not where some of that moss was at??? I'm guessing some moss causes granule loss, some doesnt???

Here some pics I took after spraying.

Roof Cleaning Bradenton FL 941-822-2454 · Guest

Great pics Matt & Mike
Kim R

Mar 4, 2011

Apple Roof Cleaning Tampa FL (813) 655-8777 wrote:

There has been some debate recently about IF it really is harmful to pressure wash roofs made from shingles. Both the ARMA and the Canadian ARMA warn against high pressure, but the question remains HOW much pressure does it really take to harm a shingle roof ?
This question reared it's head during a recent discussion on Certification. We do not wish to alienate our friends at PWNA who pressure wash roofs. However, we are the RCIA, and like to think we set the standards for roof cleaning. W/o giving my feelings on this subject, how do YOU feel, as an RCIA Member ?

I am both a no pressure roof cleaner and a pressure washer. I started in business in 1978. I pressure washed all roofs until 1991, when I learned to clean them without pressure. { I thought I invented the idea, biggrin

but within a year, I found another company doing it already, with a better system }
Anyway, I pressure washed many hundreds of shingled roofs, prior to our current method. I can state matter of factly, that a pressure washing machine, can not have the psi turned down low enough to clean a roof and not take a good % of the granules off with the algae. JUST CAN'T BE DONE! I tried all pressure settings and if the algae came off, so did the granules! A cement surface cleaner [like the roof shampoo guy uses ] is even worse! It takes a considerable amount of psi just to make it function and it's jets shoot sideways-really blowing off the granules! I tried that just once and only did a single strip down a shingled roof and finished it by regular pressure washing. That was back in 1998 - 1990
For no pressure roof cleaning, I use from 25% - 35% chlorine, plus about 1/2 gallon Ammonyx Lo and unless I brush a granule off with my foot confuse

They all remain in place, with only the algae missing!
Remember, I was a pressure washer long before I was a no pressure roof cleaner and I still pressure clean houses, pool enclosures, decks and driveways, just about every day! Just not roofs!

Chuck Bergman Soft Wash Roof Cleaning & Pressure washing.

gutterdog · Mar 4, 2011

Bergman Roof Cleaning Port Charlotte FL 941-698-1959 wrote:

Apple Roof Cleaning Tampa FL (813) 655-8777 wrote:

There has been some debate recently about IF it really is harmful to pressure wash roofs made from shingles. Both the ARMA and the Canadian ARMA warn against high pressure, but the question remains HOW much pressure does it really take to harm a shingle roof ?
This question reared it's head during a recent discussion on Certification. We do not wish to alienate our friends at PWNA who pressure wash roofs. However, we are the RCIA, and like to think we set the standards for roof cleaning. W/o giving my feelings on this subject, how do YOU feel, as an RCIA Member ?

I am both a no pressure roof cleaner and a pressure washer. I started in business in 1978. I pressure washed all roofs until 1991, when I learned to clean them without pressure. { I thought I invented the idea, but within a year, I found another company doing it already, with a better system }
Anyway, I pressure washed many hundreds of shingled roofs, prior to our current method. I can state matter of factly, that a pressure washing machine, can not have the psi turned down low enough to clean a roof and not take a good % of the granules off with the algae. JUST CAN'T BE DONE! I tried all pressure settings and if the algae came off, so did the granules! A cement surface cleaner [like the roof shampoo guy uses ] is even worse! It takes a considerable amount of psi just to make it function and it's jets shoot sideways-really blowing off the granules! I tried that just once and only did a single strip down a shingled roof and finished it by regular pressure washing. That was back in 1998 - 1990
For no pressure roof cleaning, I use from 25% - 35% chlorine, plus about 1/2 gallon Ammonyx Lo and unless I brush a granule off with my foot They all remain in place, with only the algae missing!
Remember, I was a pressure washer long before I was a no pressure roof cleaner and I still pressure clean houses, pool enclosures, decks and driveways, just about every day! Just not roofs!
Chuck Bergman Soft Wash Roof Cleaning & Pressure washing.

Me too Chuck. I washed roofs the wrong way. What came out the downspouts was no good. I stopped selling them. Till I found the RCIA!

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