Cleaning "Greenery" off fibre cement slates

sas

Hi,

been asked about this. A friend has a roof with 2 large dormers facing north. House only occupied 2 years and there is already a very significant amount of green stuff on the roof trailing down either side of the dormers.

What can safely be used to treat\remove this without doing damage to the fibre cement slates.

SAS

I can't answer the query directly, but....

Prevention is better than cure, any possibility of fitting gutters to the dormers that are not too unsightly. So called secret gutters could be fitted, a small drain is fitted behind the tiles to take the runoff from the dormers down to the main gutter.

I have heard that lead soakers should reduce the growth. Also are ther trees to the north side od the house.

Poor Uncle Tom

Maybe there lead in the dormer valleys was never oiled with patination oil and this is a result of the lead 'curing'. We used to use a strand of heavy copper wire along by the ridge on any north facing roof surface, when it rained it prevented algee and mosses growing on the roof surface.

Mellor

Lead wouldn't make it green, lead patina is grey, the oil just helps the process along.
Copper does appear to stop this growth from what I hear.

Poor Uncle Tom

Mellor wrote: »

Lead wouldn't make it green, lead patina is grey,

I understand that, it's just coincidental that the 'green' is happening where the patina occurs.

sas

Hi,

Thanks for everything so far.

Regarding the use of gutters.

Off the top of my head I can't remember whether there are gutters in place or not. Correct me if I'm wrong though but when gutters are used on dormers, doesn't the downpipe usually empty directly onto the roof anyway. So it may reduce the are affected by the growth but there will still be some on all likelihood?

Suggestion for the use of copper

This is something that specifically came up for my own house recently. The supplier of my roofing materials had this to say on it. There is a copper edge apron product that is laid before your ridge capping which leaves a small amout of copper visible either side of the ridge. This when it oxidizes would keep about the first 6 - 8 feet of my roof (running down the slope from the capping) clean. However, if you have a large span (20ft in my case) then the only option that the Rep believes will make any difference is a full copper capping. When said I'd be wasting my money if I didn't go with the full capping if this is what I wanted to prevent. He however advised to forget about it. Given that I don't thing the vedigris green of aged copper will suit my home I'm not interested in the full ridge.

All thoughts greatly appreciated as always. This is a treatment situation now however. Is there some based copper based liquid that could bre sprayed on that anyone is aware of?

mrgaa1

if you can get your hands on a product called "RED LABEL" - its not a whiskey This will remove it for you - but again like all other products try it on a spare tile. You will have to clean the entire roof - as no matter what product you use the area you clean will look different to others.
Also there is no way of stopping it coming back - its just our weather. If you ask older people they'll tell you they haven't seen it like this before.

Rooferman

Hi, If you have a good head for heights try putting copper grease on each side of the ridge tiles. You can get it in a motor factors, mechanics use it on brakes but it also dissolves the greenery on slate / tile roofs. Takes a few weeks to work and needs to be topped up once a year but its a fraction of the cost of fitting copper strips.

sas wrote: »

Hi,

Thanks for everything so far.

Regarding the use of gutters.

Off the top of my head I can't remember whether there are gutters in place or not. Correct me if I'm wrong though but when gutters are used on dormers, doesn't the downpipe usually empty directly onto the roof anyway. So it may reduce the are affected by the growth but there will still be some on all likelihood?

Suggestion for the use of copper

This is something that specifically came up for my own house recently. The supplier of my roofing materials had this to say on it. There is a copper edge apron product that is laid before your ridge capping which leaves a small amout of copper visible either side of the ridge. This when it oxidizes would keep about the first 6 - 8 feet of my roof (running down the slope from the capping) clean. However, if you have a large span (20ft in my case) then the only option that the Rep believes will make any difference is a full copper capping. When said I'd be wasting my money if I didn't go with the full capping if this is what I wanted to prevent. He however advised to forget about it. Given that I don't thing the vedigris green of aged copper will suit my home I'm not interested in the full ridge.

All thoughts greatly appreciated as always. This is a treatment situation now however. Is there some based copper based liquid that could bre sprayed on that anyone is aware of?