Moss scraping
| Moss scraping | |
| Type | Roof cleaning method |
|---|---|
| Agent | Hand tool |
| Removes | Moss; not lichen or algae |
| Defined by | Trade practice; no statute or standard |
Moss scraping is the removal of moss from a roof by hand, with a scraper or brush, without water or chemical. It is the oldest method and the most controllable, and it addresses only the growth that has bulk. No statute or published standard defines the method, so the description here is of established trade practice and carries no citation for the technique itself. What is regulated is the surrounding activity: the work is work at height,[1] and any biocidal product applied must be authorised for that use.[2]
What it removes and what it leaves[edit]
Scraping takes moss, which sits on the surface and in the laps and can be lifted off it. It does not take lichen, which adheres too closely to be scraped without taking surface with it, and there is nothing to scrape in the case of algae.
A scraped roof is therefore a roof with the moss removed and the lichen and staining still present, which is a partial result rather than a poor one, and worth saying plainly because the difference is visible to the owner afterwards.
Control[edit]
Its advantage is that the operative can see and feel what is being removed and can stop. There is no jet driving water into a lap and no chemical run-off. On a fragile or historic covering that control is the reason to choose it.
The cost is time, and that it puts the operative on the roof for the duration, which is both a work at height exposure[1] and a source of the point loading that cracks tiles and shifts slates on older roofs.
Regrowth[edit]
Scraping removes what is there and kills nothing, so moss returns from what remains in the laps and from spores in the surrounding conditions. Where scraping is followed by a biocidal treatment the two do different jobs — one removes bulk, the other slows return — and any product used remains subject to authorisation for that use.[2]
See also
References
- abThe Work at Height Regulations 2005. legislation.gov.uk. Retrieved 2026-09-05
- abRegulation (EU) No 528/2012 concerning the making available on the market and use of biocidal products. legislation.gov.uk. Retrieved 2026-09-05