New Pitsligo · Aberdeenshire
Roof Cleaning & Moss Removal in North Aberdeenshire
Moss on a roof is not just untidy. It holds water against the slate, and water that cannot drain is what does the damage when it freezes.
Why moss matters on a north-facing slope
Damp, shaded, and rarely dried out by direct sun — north-facing pitches in this part of Aberdeenshire grow moss faster than anything. The moss sits in the laps between slates and acts like a sponge. In winter that trapped water freezes, expands, and lifts the slate or opens up a hairline crack in a concrete tile. Lumps of moss also wash down and block the gutter and the downpipe, which starts the problem described on our guttering page.
We do not pressure wash roofs
This is worth being blunt about, because it is sold widely and it damages roofs. A high-pressure lance on a concrete tile strips the factory surface off it, exposing the soft aggregate underneath, and the tile then holds more dirt and weathers faster than before you started. On slate it drives water up under the laps and onto the sarking, and it will crack old slate outright. A roof that has been pressure washed usually looks worse two years later than one that was left alone.
How we do it instead
- Moss scraped off by hand, slate by slate, working down the roof
- Gutters and downpipes cleared of the debris afterwards and flushed through
- A biocide treatment applied to kill the remaining spores so it is slower to come back
- Any slipped or cracked slates we uncover pointed out to you, with a price to fix them
It is slower than a pressure washer and it is the only method that does not shorten the life of the roof.
What cleaning will not fix
If a roof is at the end of its life, cleaning it will not extend it, and stripping heavy moss off a nail-sick roof can bring slates down with it. We will tell you before we start if that is what you have, rather than taking payment for a clean and leaving you with a worse roof than you began with. In that case the money is better spent on repairs or a new roof.
Questions about roof cleaning
How long before the moss comes back?
On a shaded north-facing roof, expect it to start returning within a few years. The biocide treatment slows it considerably but nothing stops it permanently in this climate.
Will cleaning my roof stop a leak?
Sometimes, if the leak is caused by moss damming water in the laps. More often the clean reveals the real cause, which we can then price for you.
Will cleaning damage the slates?
Not the way we do it. Scraping by hand is slower than a pressure washer and it is the only method that does not take years off the covering. If a slate breaks because it was already cracked under the moss, we will tell you and price the replacement.
Moss taking over the roof?
Hand-stripped and treated, never pressure washed. We will tell you first if the roof is too far gone for cleaning to be worth your money.