Professional Roof Cleaning in Lancashire

Why Lancashire roofs go green faster than most

Lancashire takes a lot of rain. Most of the county sits between 1,000 and 1,400mm a year, and up against the Pennines it is more than that. Rain on its own is not the problem. The problem is that a roof here rarely gets a long enough dry spell to properly dry out, so the north and east pitches stay damp from October right through to March.

That is exactly what moss, algae and lichen want. Add the prevailing westerly wind carrying spores off open moorland and farmland, and a roof in Rossendale, Burnley or the Ribble Valley will carry visible growth within five or six years of being laid. The same roof in the south east of England might take fifteen.

It is why roof cleaning here is maintenance rather than a luxury. A roof that is cleaned and treated every few years will outlast one that is left, by a long way.

What moss actually does up there

The cosmetic side is obvious enough. What people miss is what is happening underneath. Moss holds water against the tile, so instead of shedding rain the roof stays wet. Through a Lancashire winter that water freezes and expands inside the pores of the tile, and each cycle takes a bit more of the surface off. That is how a concrete tile goes from smooth to crumbly.

It also gets into the laps. Moss growing between overlapping tiles lifts them slightly and lets wind-driven rain track sideways and underneath, which is how you end up with damp in the loft on a roof that has no obvious hole in it.

And it ends up in the gutters. Every clump that works loose washes down, blocks the outlet, and the overflow runs down the wall instead. Half the damp walls we are called out to look at start as a moss problem on the roof.

Soft washing, and why we never put pressure on a roof

We clean roofs with steam, hand scraping and low-pressure soft washing. Nothing else. No high-pressure lance ever touches a tile.

The reason is simple. A pressure washer will make a roof look clean in an afternoon, and it will take years off it. It strips the granular coating off a concrete tile and leaves the porous body exposed, so the roof soaks up water and regrows moss faster than it did before. It forces water up under the laps and into the loft. On older slate it cracks and dislodges. We have been called to plenty of roofs that were jet washed by somebody cheaper and needed a re-roof inside five years.

If a company quotes to pressure wash your roof, that is the moment to get another quote.

The biocide, and what happens in the months after

Once the growth is off, the roof is treated with a DDAC biocide. That is the part that actually matters, because scraping only removes what you can see. The spores and root structure are still in the surface of the tile, and without treatment the roof is green again in two seasons.

The biocide keeps working for months after we leave. The roof looks better the same day, then keeps improving through the following weeks as the remaining dead growth weathers off with the rain. That is normal and it is how it is supposed to work. You are not meant to see a perfectly uniform finish on day one.

Every roof clean carries a two year no-moss guarantee. If growth comes back within two years of the treatment we return and re-treat the affected area at no charge.

Slate, concrete and clay: what changes

Lancashire has a lot of natural slate, particularly on the Victorian terraces through the old mill towns. Slate is hard-wearing but the nails and the laths underneath are usually the weak point, so it is treated gently and nobody walks on it.

Concrete interlocking tiles are the most common thing we clean, because they went on nearly every post-war estate in the county and they are the most vulnerable to surface loss. Clay is less common but very unforgiving of pressure.

The method is the same in principle for all three and the pressure and dwell times change. That is what a survey is for, and it is why an honest quote comes after somebody has actually looked at the roof.

Access, and when scaffolding is genuinely needed

Most domestic roofs are cleaned from ladders and roof ladders with the operative harnessed, working off the edge and using poles and lances to reach up the pitch. Nobody walks across the tiles if it can be avoided, because that does its own damage.

Scaffold is only needed on steep pitches, very high roofs, or where the ground will not take a ladder safely. If it is needed we will tell you before we quote, not after we have started, because it changes the price materially.

We are fully insured for work at height and the documents come with the quote.

Gutters, paths and the clear up

The gutters are cleared as part of every roof clean. There is no point taking a hundredweight of moss off a roof and leaving it sitting in the guttering, and anybody who does that has not finished the job.

Drives, paths, patios and windows are washed down before we leave. See gutter cleaning if the gutters are the main reason you are calling, and moss removal for the detail on the treatment itself.

What it costs and how often

Price depends on the size and pitch of the roof, how much growth is on it, the tile type and how we get to it. A standard three-bed semi is a different job to a detached with three pitches and a conservatory in the way.

The quote is fixed before we start. Most Lancashire roofs want doing every four to five years, and the treated ones go longer. Send a couple of photos from the ground and the address and you will normally have a price the same day. See areas we cover for the towns we work in.