Moss On A Roof

likelylad32

A customer called me out this week to take a look at their roof. In certain places (under trees) there is moss growing on the shingles. The customer wants it cleaned off. Anyone got any ideas how I could do it without damaging or having to replace the shingles.

Shep Spear

I always like to fix before I bomb and replace.


For moss, mildew and similar black/green crap I have a method that works perfectly for me -- I learned it from an old-timey painter.

• *Take a small pump sprayer and add 1 gallon of household bleach fill with water and spray the effected area.
• *Repeat the first step and ad a squirt of dish detergent and Jomax per instructions on the container. ( the Jomax will enhance the bleaching action and reduce the recurrence of the problem.)
• *For particularly tough 'crap' I sometimes brush the surface with a masonry brush or corn broom -- power washers are often too much and will ruin the siding or the finish on the siding.
• *Rinse - blast with stream from the hose.

There are probably other products other than Jomax, but decades of success keeps me reaching for this on the shelf.
Try it, you'll like it. Shep Spear

kubie

sometime you can buy those zink strips that install under the top row of shingles and laps over the next row. the zink is supposed to react with the rain and moss and other wont grow. havent tried these strips, so i cant say if they work or not.

johnk

Zinc strips are only effective for maybe 4-5 courses.They would have to be installed every 4-5 courses to be effective.How ugly would that be.Scrape of moss gently,I usually uses a trowel.Spread Tide powdered soap along ridgeline,let rain do the rest.

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"A Roof is only as good as it is Applied"

kubie

4 or 5 courses? wow yeah that would look bad

RandyB1986

Get sodium hypochlorite 12.5% from a pool company, mix gallon of SH with gallon of water. The moss and lichen will turn white almost immediately and will fall off over time on its own. Explain to the owner that the moss is gripping the granules and if you attempt to forcefully remove the moss you will remove more granules and more than likely large patches of them. It is better to let the moss die and loosen it's hold and fall off naturally. It wont take long, SH will kill it.

johnk

Another good one-1 litre bleach-3 litres water 1/4 cup trisodium phosphate.Mix and spray.

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"A Roof is only as good as it is Applied"

olyteddy

Wouldn't that result in 6.25% sodium hypochlorite, same as the buck a gallon stuff (undiluted) from the grocery store???

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naptown CR

Tell him to just let it grow. If he gets enough on there he will get LEED points for a green roof

likelylad32

It's worth a try. LOL

RandyB1986

Depends. Clorox for example has bleach in a variety of flavors that range in 1.25% Sodium Hypochlorite up to 6.15%......but all flavors of Clorox bleach also contain Sodium Hydroxide(which some professionals claim isnt good).

johnk

What flavor is your favorite?I like the blue raspberry,lol.

__________________
"A Roof is only as good as it is Applied"

Broken_Roofer

There's a few products you can use, however, the one thing to be wary of is what type of moss or fungus are you dealing with?

Is it a lichen? If so that variety has a root that becomes embedded into the shingle mat, removing it with a spade, spud bar, pitch fork, knife, etc... will not fully remove it and may cause further damage to the shingle if the root structure decides to be a pest and take some shingle(s) with it.

Is it a fungus, most of those can be treated with a dilute bleach solution as others have mentioned. There's also a product called Shingle Shield which we have used in the past with decent success. We have also utilized the zinc strips, while they may not be attractive to the eye, most of our customers who want that solution would rather have the zinc strip seen versus the moss and fungus on their roofs.

However, the ultimate solution would be to remove the old organic shingles and install fiberglass shingles in their place.

Cole82

I know this is about a month old but saw this and remembered this thread.
http://www.pjfitz.com/roofing-cleaning.php

Tom Struble

my understanding is that copper strips might be more effective

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Tom

woodchuck2

I have cleaned several roofs like this using a pressure washer , it is quick and easy.

naptown CR

you are a brave man. roof and pressure washer should not be used n the same sentence

neolitic

There seems to be some confusion
here.
The zinc strips are to help prevent
the black mildew stains on
white roofs, not moss.
For moss, killing it with the sodium
hypochlorite is the least damaging
technique I've seen.

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(Sorry....it seems there really are dumb questions)

woodchuck2

Maybe i seem like a fool but why not? The steepest pitch i have done is 5-12 so i dont slip and fall off, you only spray downward with a low pressure nozzle and you use a stiff bristle brush for the heavier moss/lichen. If the shingles cant handle low to moderate pressure water in the proper "downward" direction then i would question the application and integrity of the shingle. The shingles are designed to withstand heavy rains, high winds and if properly installed ice backups, it would seem they could handle a heavy spray.
If it is the granules that may be damaged it is very little if any at all. The couple i have done were 15-20yrs old too, the shingles were not in new condition to begin with and we all know moss/lichen do not grow overnight or in just a few years. I think you will find that just walking on the roof with shingles this age will loosen the granules.

Grumpy

You can try to use a low pressure power wash to remove the moss, but furst try brushing it off and use the power washer to remove anything inground. When washign a roof high GPM is more important than high PSI. Also a chemical detergant is preferred to let the chemical do the work and then rinse the roof.

To keep the moss from coming back you may consider zinc or copper strips.

It's very very easy to damage a roof with a power washer, and you will lose some granuals no matter what the pressure is on the washer, so be careful!