Professional Roof Cleaning in Bolton, Greater Manchester

Living under the West Pennine Moors

Bolton sits right under the West Pennine Moors, with Winter Hill on the skyline, and that geography sets the weather. Around 1,050mm of rain a year in the town and considerably more on the higher ground north of it.

Moorland air carries spores. Combine that with long damp winters and north-facing pitches that see no direct sun between October and March, and you have ideal growing conditions for moss, algae and lichen. A roof in Bolton will show visible growth within five or six years of being laid.

The pattern is very predictable street by street. Sheltered south-facing pitches stay reasonably clean for a decade. North-facing pitches on the same street are green in half that.

Stone in the north, render and tile in the south

Bolton has two quite different housing stocks and they want different handling. North of the town, out through Bromley Cross, Egerton and Smithills, there is a lot of stone with natural slate, some of it Victorian and some considerably older.

South and west, through Farnworth, Little Lever, Westhoughton and the post-war estates, it is mostly brick and render with concrete interlocking tiles. Concrete is the material that suffers most from being cleaned badly, because its weather resistance sits in a thin granular surface layer.

Horwich is a mix of both, often on the same street. We survey before quoting rather than assuming.

Why moss takes hold so fast on a north pitch

A north-facing roof in Bolton is effectively in shade for the whole winter. It gets wet, and then it stays wet, because there is never enough sun or wind on it to dry the surface out.

Moss only needs a damp surface and a bit of texture to root into. Once it is established along the lap lines it holds even more water against the tiles, which makes the conditions better for more moss. It accelerates.

That is also where the damage starts. Water held against a tile through repeated freeze-thaw cycles breaks the surface down, and moss in the laps lifts the tiles enough to let wind-driven rain track underneath.

The clean: careful removal, then the treatment that matters

The growth is taken off by hand and with steam, worked from a roof ladder with the operative harnessed and without walking across the tiles where it can be avoided.

Then the whole roof is treated with a DDAC biocide, including the areas that already look clean. That is the stage that buys you years rather than months, because it kills the spores and root structure left in the surface of the tile.

The roof keeps improving for weeks afterwards as the dead growth weathers off. Two year no-moss guarantee on every job.

Never pressure wash a roof, and what happens if you do

We do not own a machine we would be willing to point at a roof, and that is deliberate. High pressure strips the granular surface off a concrete tile and leaves it porous, so it absorbs water, degrades faster in frost and grows moss quicker than before.

On the slate around Egerton and Bromley Cross it cracks slates and lifts them off their nails. On any roof it forces water up under the laps and into the loft.

The result looks excellent for about a fortnight. The cost turns up as accelerated tile failure over the following five to ten years.

Horwich, Egerton and the high ground

Anything up towards Winter Hill, Egerton, Belmont or the top of Horwich takes noticeably more weather than the town centre. More wind, more driven rain, more spores off the moor and more material in the gutters.

Those properties are better on a three to four year cycle for the roof and annual for the gutters. Down in the more sheltered wooded parts of Bromley Cross the driver is leaf fall and shade instead, which lands you in much the same place.

Clearing up: gutters, drives and glass

Gutters are cleared of everything that has come off the roof, and the downpipes are run through to confirm they are clear at the bottom. That is part of the roof job rather than an extra.

Drives, paths and windows are washed down before we leave. See gutter cleaning in Bolton for the gutter method, or driveway cleaning in Bolton if the drive wants doing in the same visit.

Cost and frequency

The price is driven by roof area, pitch, tile type, how heavy the growth is and how we get access to it. A terrace in Farnworth and a detached in Egerton with three pitches are not comparable jobs, which is why there is no price list.

You get a fixed price in writing before anything starts. Send the address and a couple of photos from the ground and it is usually back the same day. Most treated roofs in Bolton want revisiting every four to five years.