Moss removal without wrecking the roof surface
North-facing Chiltern roofs moss up quickly, and a pressure washer is the fastest way to ruin them - it strips the surface off tiles and drives water back under the laps. We scrape, soft-wash and treat instead.
What we do
The detail on moss removal
Why Chiltern roofs moss up
Moss wants shade, damp and something to hold onto. This area supplies all three: a lot of mature tree cover, north-facing slopes that never get direct sun through the winter, and plenty of older concrete tile that's rough enough to give spores a foothold. Once a roof has moss it holds water against the tile surface, which accelerates the erosion that made it hospitable in the first place. That's why it comes back faster each time if nothing is done about the cause.
Why we don't pressure wash
A pressure washer will take moss off a roof in an afternoon and it is genuinely tempting, which is why so many people offer it. It also blasts the cement face off concrete tiles, taking years off their life in one visit; it drives water up under the laps and into the roof space; and it can dislodge tiles and break the mortar at ridges and verges. A roof that's been pressure washed usually looks superb for a season and then greens up worse than before, because the surface is now rougher than it was. We scrape by hand and soft-wash at low pressure instead. It takes longer. It's the reason the roof is still there in twenty years.
Scrape, soft-wash and treat
We work down the roof from the ridge, lifting the moss off by hand and with a scraper so the tiles aren't stressed, then soft-wash at low pressure to take off the residue and the algae film underneath. Once it's clean and dry we apply a biocide, which kills the spores that a scrape alone leaves behind. Skipping the biocide is why some moss removal jobs are back to square one inside two years - you've removed the growth but left everything it grows from.
Gutters and downpipes afterwards
All that moss ends up somewhere, and that somewhere is your gutters. Clearing the gutters and rodding the downpipes is part of the job rather than an extra - leaving a roof clean and the gutters packed solid would just move the problem. We bag the debris and take it away.
How often it needs doing
For most roofs around Chesham, a treated roof stays clear for around three to five years before it's worth looking at again - less if you're under trees on a north slope, more on an open south-facing roof. We'd rather tell you honestly that yours doesn't need doing yet than sell you a visit. Cutting back overhanging branches, where that's possible, does more for the problem than anything we can apply.
When moss removal isn't the answer
If the tiles underneath are already eroded - rough, patchy, aggregate showing through - then cleaning them is cosmetic and won't add life to the roof. In that case we'll tell you the roof is near the end and that the money is better spent elsewhere. Moss is sometimes a symptom rather than the problem.
How it works
Four steps, in this order
01
Free inspection
We come out, get up and look properly, and photograph anything you can't see from the ground. If it turns out you don't need the work, we'll say so.
02
Written fixed quote
You get the price in writing with the materials named and the scaffold and waste included. It doesn't move unless we find something hidden and agree it with you first.
03
Scaffold and works
We book the scaffold, give you a start date and keep to it. The site gets cleared at the end of every day, not just at the end of the job.
04
Sign-off
We walk you round the finished work with the before and after photographs, clear the scaffold, and leave you the details of what was used and where.
What it costs
How we price moss removal
Priced per visit by roof area, access and how heavy the growth is, with the gutter clear included rather than added on. If we look at it and think the roof is too far gone for cleaning to be worth your money, we'll tell you that instead of quoting.
Questions
The things people ask
Will you pressure wash my roof?
No. It strips the surface off concrete tiles, forces water under the laps and shortens the life of the roof. We scrape by hand and soft-wash at low pressure. If you specifically want pressure washing, we're the wrong firm for the job.
How long before the moss comes back?
Three to five years on most roofs once it's been treated with biocide. Sooner if you're heavily shaded by trees on a north-facing slope.
Is moss actually damaging my roof?
It holds water against the tile surface, which speeds up erosion and freeze-thaw damage, and it blocks gutters when it comes off. On a sound roof it's worth removing. On a roof that's already eroded it's a symptom of a bigger problem.
Do you use chemicals, and are they safe?
We apply a biocide after cleaning. We cover and rinse planting below the working area, and we'll tell you beforehand if you need to move anything or keep pets in.
Can I do it myself from a ladder?
We'd rather you didn't. Wet moss on a pitched roof is genuinely slippery, and most of the falls that hurt people are from ladders. It's also easy to crack tiles by putting weight in the wrong place.
Where we work
Moss Removal across Buckinghamshire and west Hertfordshire
We carry out moss removal in Chesham, Chesham Bois, Ley Hill, Hyde Heath, Amersham, Ashley Green, Latimer & Chenies, Little Chalfont, Bovingdon, Great Missenden, Berkhamsted and Chalfont St Giles, and everywhere else within 10 miles of Chesham. See the full list of areas we cover.
Related services
Need moss removal doing?
Tell us what the roof is doing and we'll come and look at it. Free inspection, written fixed price.