removing moss from roof

FFHillbilly

At my last house when it got rendered as I had scaffold up and some free time I scraped off all the moss, was really surprised to remove 4 or 5 20kg bags of it, at the time I felt that was a lot but in terms of extra percentage on the roof it's nothing.
reason for removal was because it would block gutters, and always blow down and start growing on my patio or lawn, or stain the new white render and generally look untidy
however, It seemed to be a complete waste of time as the neighbours moss just ended up all over my patio/lawn/gutters instead, and as it was a mid terrace the moss just migrated back in a few years and I couldn't tell the difference

I think it would take a few years and you'd be back to square one, if moss has grown there then there's nothing stopping it growing again. 

sevenhills

My outbuilding flat roof has some moss, I am wondering if I should scrape the moss off and paint it?

WustyRex

Hi, I did spend a few years cleaning moss of many a roof, and despite all the comments on previous posts about this, I renovated 1400 in 2 years. With a 2000 psi power washer.
I also had a record of 4.22 tons of wet moss collected in a skip, off one bungalow.. 4.2 tons extra weight on a concrete tile roof.
Marley state that concrete tiles should last 35-45 years , but moss can dig roots into the surface and loosen it reducing the lifespan.
If you brush it like cutting your lawn, it will return. If your under trees like Sycamore (the worst), it will regrow being fed by sap.

PS I never once had an issue with water ingress and replaced any broken tiles en route. Not many briken despite being 21 stone at the time (6ft 3" if you are wondering). 

Adding fungiside or copper sulphate helps. 

Section62

WustyRex said:

Hi, I did spend a few years cleaning moss of many a roof, and despite all the comments on previous posts about this, I renovated 1400 in 2 years. With a 2000 psi power washer.
I also had a record of 4.22 tons of wet moss collected in a skip, off one bungalow.. 4.2 tons extra weight on a concrete tile roof.
Marley state that concrete tiles should last 35-45 years , but moss can dig roots into the surface and loosen it reducing the lifespan.
If you brush it like cutting your lawn, it will return. If your under trees like Sycamore (the worst), it will regrow being fed by sap.

PS I never once had an issue with water ingress and replaced any broken tiles en route. Not many briken despite being 21 stone at the time (6ft 3" if you are wondering). 

Adding fungiside or copper sulphate helps. 

That sounds rather like the spiel of a roof "renovator" trying to convince people they need to have their roof cleaned damaged with a "2000 psi" jet of water.

Moss roots will do little or no damage to concrete tiles.  Meanwhile, high pressure jets of water are used in the industry to cut through concrete.  Of the two, the moss is less likely to do damage to a roof.

"4.22 tons" of wet moss sounds like a lot, but normal amounts of moss distributed over the whole of the roof surface doesn't make a great deal of difference to the structure.

This is a money saving forum, people can save money by not risking having their roof damaged by contractors trying to make a quick buck out of them.

Pondskater

I watched them powerwashing the roof across the road from me, looked loverly when done. Howeve, over the next few months I watched the concrete that filled the dips between the ridge tiles and the roof tiles slowly sliding down the roof. This year I have had a lovely view of hundeds of starling setting up home in every single space.

daivid

WustyRex said:

Hi, I did spend a few years cleaning moss of many a roof, and despite all the comments on previous posts about this, I renovated 1400 in 2 years. With a 2000 psi power washer.
I also had a record of 4.22 tons of wet moss collected in a skip, off one bungalow.. 4.2 tons extra weight on a concrete tile roof.
Marley state that concrete tiles should last 35-45 years , but moss can dig roots into the surface and loosen it reducing the lifespan.
If you brush it like cutting your lawn, it will return. If your under trees like Sycamore (the worst), it will regrow being fed by sap.

PS I never once had an issue with water ingress and replaced any broken tiles en route. Not many briken despite being 21 stone at the time (6ft 3" if you are wondering). 

Adding fungiside or copper sulphate helps. 

Apparently a typical roof for a 3 bed bungalow has an area of 100 sq m, typical weights of tiles per sq m I've found are 47kg for interlocking concrete, 73.2 kg for plain concrete. These would give total weights between 4.7 tonnes, and 7.32 tonnes for the tiles on a roof, your claim of wet moss weighing 4.22 tons from one roof sounds more than a little fishy (the equivalent of about 11 cubic m of wet sphagnum moss - that skip must have been piled high!)

MACKEM99

twopenny said:

Well you can have a good laugh when their moss grows back next year 

Since we started to insulate our lofts to within an inch of their lives I've noticed it's made ideall conditions for moss and llichen to grow but even with my old rosemary tiles 90yrs old it didn't cause any harm.

I too wait for the birds to do their job. Some goes in the gutter but often they chuck that out too. Nothing a quick  grab and chuck can't handle. Goes on the compost heap.

I guess I won't cut my grass as it will just grow back again.😁