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!
Hi @Joan_J,
I'd suggest a bit of a combination between 30 Seconds 5L Roof Treatment Concentrate and possibly your pressure sprayer. You can either spray the product and leave it for up to 6 months before the lichen fully decays and washes off in the rain or spray as much as you can off now with your pressure sprayer before applying the product.
It's best to get the 30 seconds product on there as soon as possible and let it do its work. I'd recommend doing the work from a ladder if possible, as it would be pretty dangerous to get onto the slippery Colorbond roof whilst it's wet. Your pressure sprayer won't do much to the lichen unless you can get the nozzle up close to it. If that requires you to get on the roof, I would advise you to leave it to the professionals.
Unfortunately, you might find that the lichen has secreted destructive acids causing damage to roof materials. This might appear as a discolouration even after the lichen is removed.
Please let me know if you have any questions.
Mitchell
l dont think it lichen because because, the spots on my roof is black, does that mean its more likely mould . does the 30 second product work on mould and is it safe for colorbond roof
Hi @Cranswick,
It could be mould or mildew, though mould doesn't typically grow on a roof. Looking at the specifications of the 30 Seconds 5L Roof Treatment Concentrate it does say that it is suitable for Coloured steel. However, as mentioned in your discussion, chemical cleaners are not listed for use in the technical specifications of Colorbond steel.
This cleaner should work for most organic issues on a roof.
Thanks, l will see if l can take a photo later to post here, its just on one section of the roof about 1 meter wide and 2.5 meters long covered in black spots or streaks . Even though chemical cleaners are not listed , Would a one off spray of that small roof section be very unlikely to harm the roof, l will only be spraying that section not the entire roof. l was thinking they wouldnt say on the ' 30 second package ' its suitable for colorbond roofs if it can damage the roof, then if people roofs were damaged by it they would get sued. If l give it a spray with ' 30 secod cleaner' how long will it take for the black spots to go away ? should l hose it down afterwards or let the 30 second cleaner sit there overnight
They've likely done testing and found it doesn't damage Colorbond @Cranswick. Given that they are recommending it for that purpose, I would say it's very unlikely that it would damage the roof.
However, if you can wait until Monday, I'd like to contact the manufacturer directly to get a definitive answer on Colorbond. The product description notes that it is suitable for coloured steel, though I'm not finding that information on the 30 Seconds website. There, it only states "steel roofs" and not painted steel roofs.
I think it would be wise to have this confirmed before applying it to your roof.
Thanks, lm now thinking l might get my plumber who cleans my roof to scrub it with detergent which will be safer, one thing l am a bit worried about is l read about something called " Black Rust" l hope its just some sort of fungus and not " Black Rust" . Would it be unlikely to be black rust ,? is that common or rare, if its black rust would that be a series expensive problem, the roof is 15 years old and 2 km from the ocean. l will try and post some photos later
That's typically seen at points where the sheeting is damaged and the inner steel exposed, like on cut edges @Cranswick. It's unlikely to occur mid-sheet. Repair would be a process of sanding the area back, treating the rust and re-coating. I'm not aware of how costly that would be, and you'd likely need to get some quotes.I wouldn't jump to that conclusion until the area is assessed; it's most likely some organic matter.
Heres a photo , can you tell me what you think the black stuff on the roof is , thanks
Hello @Cranswick
It appears to be mould and mildew along with a form of dust deposit. It does not appear to be a heavy rust infestation. In regards to the cleaner, Mitchell will be following this up with our supplier of 30 seconds. Let's wait to see what they have to say in regards to making sure that using the cleaner is safe.
If you have any other questions we can help with, please let us know.
Eric
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
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.
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
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.
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.
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
No, I think it's going to take some agitation @Cranswick. Perhaps your plumber could give a scrub for you?
