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Hi. Im interested to learn the best method "to remove moss from a flat gravelled roof".

Intend doing the work myself. Never done this job before and im inexperienced in diy. The roof (and its gravel) is older than 15yrs and the extension on which it sits is likely to be rebuilt within 3yrs. The roof does not leak.

My plan is to remove the moss manually with a paint scraper, as opposed to a jet wash (roof damage?). I suspect that as i scrape the moss i will also remove gravel/chippings. So in addition to removing moss im expecting to replenish gravel covering to improve UV protection.

Proposed process
1. Not sure this step necessary but 1 or 2 days before starting the scraping i was going to spray on fungicide (baticlean seems ok) over moss to initiate the moss killing process and thought, although this might be over the top, the moss might lift more easierly if on the wane. Plus an initial coat of fungicide wouldnt do no harm  What u think.
2. Use a normal paint scraper to remove moss from roof and i expect that as i remove moss i cant help also removing the adjoining gravel. Take care not to tear roof surface layer.
3. I was not planning a specific activity to remove all the gravel off the roof.  I saw gravel being removed only in patches, in line with areas where moss is removed. In areas where there was no moss the gravel would remain as is. Note .. will probably fungicide these untouched gravel only areas and likely to top gravel up to give a denser UV protection covering.
4. Once moss/gravel removed, sweep those areas and spray on a fungicide (baticlean looks ok??). 1 coat??
5. Replenish and evenly spread roof gravel.
JOB DONE ????

Bleach is quite effective at killing moss. Buy cheap thin bleach (not the thick kind, that has soap in it) and spray it on the moss on a dry but not sunny day. The moss will be killed and you will be able to sweep it up without damaging the roof underneath.

Rorschach wrote: ↑Tue Feb 16, 2021 8:21 am Bleach is quite effective at killing moss.

I suspect that bleach is also much safer from an ecological viewpoint if it rains after application, bleach will often go down drains in normal usage, moss-killer is probably not safe in that respect.

What I don't understand is the general antipathy towards moss anywhere and everywhere.

ayjay wrote: ↑Tue Feb 16, 2021 8:31 am

Rorschach wrote: ↑Tue Feb 16, 2021 8:21 am Bleach is quite effective at killing moss.

I suspect that bleach is also much safer from an ecological viewpoint if it rains after application, bleach will often go down drains in normal usage, moss-killer is probably not safe in that respect.

What I don't understand is the general antipathy towards moss anywhere and everywhere.

The "roots" of the moss can cause damage to surfaces, something like a concrete roof tile is usually ok as they last for decades but flat roofs can be damaged more quickly.

Bleach is quite safe, in the presence of UV light it breaks down within hours into what is basically salty water. This why your local sewage plant is quite happy for you to pour it down your toilet and drains, it breaks down into a safe chemical that can be easily removed from the water. Other chemicals such as weed killers are much more dangerous for water supplies.