How to clean colorbond roof

[Joan_J]

My Colorbond roof appears to have mould on it which has been there since I purchased the property. I’m wondering if there’s a way to clean it off? I have a pressure cleaner from Bunnings but unsure if that’s enough. Thanks!

[Cranswick]

thanks ,would you say it looks like no rust at all ? and its  if its mould should that be something l should get a professional to look at or is it something l can treat myself with 30 second spray, is  there a danger mould on the roof could spread to inside the house

[EricL]

Hello @Cranswick 

I believe that it is something that you can treat yourself. You can always do a preliminary clean with traditional water and detergent in combination with a Sabco Professional 2.44m Extension Pole - 2.44m and compatible brush head. If the dark deposits refuse to budge, then using the 30 Seconds will be the next step, but we'll find out on Monday if its compatible with your roofing material. 

The mould on your roof is usually confined to outside area. If you have a leak in your ceiling, then it becomes a different conversation all together.

If you need further assistance, please let us know.

Eric

[Cranswick]

THanks, yes l only noticed the black stuff a few months ago so l dont think its been there long ,, my big fear would be if it speads inside  to the timber roof frame but you mentioned that is usually stays on the roof . My roof is 15 years old, l had a plumber inspect the roof a year ago when he cleaned the gutters and he said its in good condition with no leaks, so as long as theres no leaks does that mean the mould would be unlikely to spread to inside the roof cavity

[EricL]

Hi @Cranswick 

Yes, certain environmental conditions must be present in order for mould to manifest and spread. Damp wet conditions, warm areas with no air movement and lack of sunlight all contribute to mould infestation. So, when your plumber says there are no leaks, its always good news.

Eric

[MitchellMc]

Hi @Cranswick,

I don't think there are any concerns that this could spread within your roof cavity.

I've confirmed with the manufacturer that the 30 Seconds Roof treatment is suitable for Colorbond steel roofs. However, looking at your image, this might just be general grime that can be removed with dishwashing detergent, warm water and a soft-bristle scrubbing brush. 

Mitchell

[Cranswick]

thanks, hopefully its grime not mould,  l will try dishwashing liquid first , its easy to spay it on the roof to cover it all but l cannot climb on the roof to scrub it  l  will need a telecopic pole with a brush to scrub it, do you think just spray it all with detergent then hosing it down might work without scrubbing it

[MitchellMc]

No, I think it's going to take some agitation @Cranswick. Perhaps your plumber could give a scrub for you?

Mitchell