How to control moss on tile roof with aluminium gutters?

[aussiblue]

OK; so this year appears to have been extremely conducive to moss growing on tile roofs and in gutters. Unfortunately, most recommended treatments involve the use of cleaners that contain acids (albeit as mild as vinegar) and other chemicals that will attack and damage my Colortuff Continuous Aluminium Gutters. Does anyone know of suitable Moss cleaner or biocide that won't damage aluminium or I will just have to rely on my pressure washer to do the job with plain water?  BTW I see the, previously Canning-vale based, Aluminium Gutter Supplies/Colortuff, where I bought mu gutters, ceased business in September 2021 according to the ABN lookup. The business still come up in Google and other web search engines but their website no longer exists.   That going to make it hard to find compatible replacements if any is damaged and my warranty is probably of little use now. So a supplementary question is: are there any continuous aluminium gutter suppliers still around in Perth? The associated Gutter Guys installation company still seems to be around at the same address where Aluminium Gutter Supplies/Colortuff, were but there in no mention of Aluminium gutters on their site either.

[MitchellMc]

Hi @aussiblue,

Do you happen to know what coating is over the aluminium gutters? Typically it would be a hard-wearing paint such as what is applied to Colorbond. Products like 30 Seconds 5L Roof Treatment Concentrate are perfectly fine to use over these painted surfaces. Remember, the product is not contacting the aluminium; it's contacting the paint. I suspect you've read plenty of information on how vinegar and corrosive products can tarnish and eat away at aluminium. Still, this shouldn't be an issue unless you have damaged portions of your guttering where the coating is compromised.

If you are concerned, you could always do a test section to ensure there is no adverse reaction between the treatment and your gutter's paint coating.

Please let me know if you have any questions.

Mitchell

[aussiblue]

While it is coated with a colorbond type coating, It will be compromised where the down pipes have been cut in and similarly where it has been cut for the  corner joints.

[MitchellMc]

Dropper outlets are typically installed and sealed at the downpipes, and corners are finished with a sealant @aussiblue. The runoff from your roof shouldn't be able to access bare aluminium. Can you see any? Colourbond gutter is installed in a similar fashion, and there have been no reports of issues. Steel also is reactive to cleaning solutions.

The safest option might be to continue pressure spraying the roof without using chemicals.

Mitchell

[aussiblue]

The guttering was installed by me and while sealant sealant was used that was 7 years ago and I think movement of the gutters and joints from a) high winds and a tree lopper dropping some branches on the roof, gutter and down pipe; and b)  aging of the sealant and sun exposure probably means these seals are no longer 100% . I guess I go around and remove all the stainless gutter girds and reseal everything but I would rather not. And when acids do react with aluminium they tend to be considerably more destructive than when they are applied to steel and iron. There's a reason why the inside of coke, beer and soft drink cans are coated with plastic.

[EricL]

Hi @aussiblue

If you are worried about your aluminium gutter getting damaged by the chemical cleaners, I recommend that you use only a pressure washer to clean your roof. I've used a Ryobi patio cleaning attachment to clean my brick entrance and it has come up a treat. I suggest having a quick look at this discussion - Ryobi 2000psi Pressure Washer w/ deck and pavement cleaner. No chemicals were added to the mix only plain water and the pressure generated by the machine.

If you need further assistance, please let us know.

Eric