Is it worth getting your roof cleaned?

Moss looks bad, but the reason to clean a roof is drainage and early warning, not kerb appeal.

Family-run, with our own local roofers rather than subcontractors, and a 25-year written workmanship guarantee handed over before we leave. Whether you need roof cleaning or roof cleaning in Godalming, we cover the whole area.

Call 07428 300474 and Scott will tell you straight whether your roof is worth cleaning.

Is it worth getting your roof cleaned?

Usually yes, if the moss is thick enough to block gutters, hold water against tiles or push under laps. It is worth it for drainage and for spotting damage early. It is not worth it as a way of making an old, failing roof last longer, and it is never worth it under high pressure.

What moss actually does to a roof

Moss on its own does not eat tiles. What it does is hold water. A thick mat sits on the tile surface, stays damp for days after rain, and keeps the top of the tile wet through every frost. On older concrete tiles that repeated freeze and thaw is what breaks the surface down and starts the crumbling you can see from the ground.

The bigger nuisance is what comes loose. Moss sheds constantly, and it all ends up in the same place: the gutter, the outlet, the downpipe. Blocked rainwater goods overflow down the wall, soak the fascia and eventually rot the timber behind it. That is the damage that costs real money, and it starts on the roof. Gutter sizing and flow are set out in BS EN 12056, and a gutter half full of moss is not the gutter that was designed.

Growth also creeps under the tile laps and lifts the tail of the tile slightly. Wind then has something to work with. Whether you need roof cleaning or roof cleaning services Guildford, we cover the whole area, and the first thing anyone should be doing is looking at what the growth has done rather than just how it looks.

When cleaning is worth the money and when it is not

Cleaning is worth doing when the roof itself is sound and the growth is the problem. Tiles are in good order, the battens and fixings are fine, the moss is simply choking the gutters and holding damp. Take it off and you have bought yourself years of clear drainage and a roof you can actually inspect.

Cleaning is not worth doing when the roof is at the end of its life. If tiles are laminating, if nail fatigue has slates slipping every winter, if the underfelt has torn through at the eaves, a clean changes nothing except the colour. Anyone who cleans that roof and says nothing has taken your money for a cosmetic job on a roof that needs replacing. We would rather tell you the roof is finished and price the honest option.

It is also not worth doing on a roof where the access risk outweighs the gain, or where the growth is light and shaded and doing no harm at all. Some roofs simply do not need it yet. Whether you need roof cleaning or roof cleaning services Woking, we cover the whole area, and part of the survey is telling you if the answer is to leave it alone for another couple of years.

Why low pressure and hand work matter more than the result on the day

A pressure washer will strip a roof clean in an afternoon and it will also strip the sand facing off concrete tiles, drive water up under the laps into the loft, and blast the mortar out of ridge bedding. The roof looks superb and it is now worse than it was. We do not pressure wash roofs. We soft wash at low pressure and scrape the heavy moss off by hand, which is slower and does not damage the tile surface.

Hand scraping also has a second benefit. Working across a roof at close range is when you find the cracked tile, the slipped slate, the flashing that has lifted out of the chimney joint and the dry ridge fixing that has worked loose. Fixing and wind uplift are covered by BS 5534, and half the point of a clean is the inspection that comes with it. Our roof cleaning services are written up the same way, with what we found and what it needs, whether that is nothing or a small repair.

We also do not push coatings after a clean. A sealed or painted tile roof is not a repair and it makes future work harder. If someone tells you the roof needs coating straight after cleaning, ask what the coating is fixing.

How often, and what a proper job leaves behind

Most roofs in this part of the country want looking at every four or five years. North facing slopes, roofs under trees and anything with a shaded valley will go quicker. A south facing roof in open sun may go a decade with nothing worth removing.

• Gutters, valleys and outlets cleared as part of the job, not left full of scraped moss
• Growth removed without breaking the tile surface or disturbing ridge bedding
• Anything found on the way written down and priced separately, with no obligation
• Site cleared, borders and paths left as they were found
• The written 25-year workmanship guarantee handed over before the team leaves

Scott has spent more than 36 years on Surrey roofs, and the honest position on cleaning is that it is a maintenance job with real value on a sound roof and a waste of money on a failing one. We will tell you which one you have got, and we do not charge for looking.