How long until my roof looks clean?

Expect visible change within a few weeks and continued improvement over a couple of months as dead growth weathers off. Heavy lichen takes longest.

Will you walk on my tiles?

We avoid it wherever possible and work from access equipment, because foot traffic cracks older concrete tiles.

Does cleaning damage the tiles?

Softwashing does not. Pressure washing removes the tile's surface layer and can force water under the laps, which is why we do not use it on roofs.

Should I clear the gutters at the same time?

Yes. The access is already in place and the roof debris has to be removed from the gutters anyway.

Roof Cleaning Process Step by Step

Roof cleaning has a reputation problem, largely because the most visible version of it is someone on a ladder with a pressure lance producing an instantly clean roof and a garden full of tile granules. Done properly it is a slower, more careful process, and the results carry on improving for weeks after the van leaves. This guide walks through what we actually do on a domestic roof in and around Plymouth, in the order it happens, so you know what you are buying and what your roof will look like at each stage rather than being surprised on day three.

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The survey comes first

Before anything is quoted, the roof is looked at from ground level and, where safe, from a higher vantage point or by pole camera. We are checking pitch, tile type and condition, how sound the ridge and verge mortar is, whether there are slipped or cracked tiles, and how the valleys and flashings look. If a roof needs repairs, cleaning it first is the wrong order, and we will say so. Cleaning does not fix a roof and no honest company should imply it does.

This guide sits under our Roof Cleaning work, covering 20-mile radius of Plymouth.

Protecting everything below

Whatever comes off the roof lands somewhere. Downpipes are capped or gutters are cleared afterwards so debris does not simply relocate into the drains. Planting immediately beneath the elevation is wetted down or sheeted, garden furniture is moved, and cars are asked to be shifted off the drive. This part is unglamorous and it is a decent indicator of how the rest of the job will be done.

Mechanical moss removal where it is warranted

Thick moss cushions are physically removed first, by hand or with a scraper, because a treatment cannot penetrate several centimetres of wet moss. This is done working from access equipment rather than walking the tiles wherever possible, since foot traffic on old concrete tiles cracks them. Loose moss is bagged and taken away rather than swept into the borders.

The softwash treatment

A biocidal treatment is applied at low pressure across the whole roof surface, including ridge and verge, so that what remains is killed at root level. This is the part that determines how long the result lasts. Knocking moss off without treating leaves the holdfasts in place and the roof greens up again quickly, which is why some cleans seem to fail within a year or two.

Gutters, valleys and downpipes

Access is already set up, so this is the sensible moment to clear the gutters of the moss and grit that came off the roof, check the valleys are not silted, and confirm the downpipes run. A roof clean that leaves blocked gutters is an unfinished job, and the first heavy rain will make that obvious.

What happens over the following weeks

The roof will not be uniformly clean when we leave, and anyone promising that is either pressure washing or overselling. Dead growth greys, loses its grip and washes off progressively with rain and wind. Most roofs look substantially better within a few weeks and continue improving for a couple of months. On heavy lichen a follow-up application is sometimes sensible, and we will tell you at the survey if we think that is likely.

Weather and timing

Treatments need dry conditions to dwell rather than being rinsed straight off, so work is planned around the forecast. Spring through autumn is the natural window in Devon, though a settled dry spell in winter works. We would rather move a date than apply in the wrong conditions and produce a poor result.

Keeping it clean afterwards

The main things that shorten a roof clean are overhanging branches, blocked gutters holding damp against the lower courses, and a shaded north pitch. Trimming back what you can, keeping the gutters clear annually, and a light maintenance treatment every few years will hold the result far longer than doing nothing and paying for a full clean again.

Reader note: Roof cleaning: what actually happens, start to finish

Owner considering roof cleaning and wanting to know the real process.

The survey comes first: Before anything is quoted, the roof is looked at from ground level and, where safe, from a higher vantage point or by pole camera. We are checking pitch, tile type and condition, how sound the ridge and verge mortar is, whether there are slipped or cracked tiles, and how the valleys and flashings look. If a roof needs repairs, cleaning it first is the wrong order, and we will say so. Cleaning does not fix a roof and no honest company should imply it does. Protecting everything below: Whatever comes off the roof lands somewhere. Downpipes are capped or gutters are cleared afterwards so debris does not simply relocate into the drains. Planting immediately beneath the elevation is wetted down or sheeted, garden furniture is moved, and cars are asked to be shifted off the drive. This part is unglamorous and it is a decent indicator of how the rest of the job will be done. Mechanical moss removal where it is warranted: Thick moss cushions are physically removed first, by hand or with a scraper, because a treatment cannot penetrate several centimetres of wet moss. This is done working from access equipment rather than walking the tiles wherever possible, since foot traffic on old concrete tiles cracks them. Loose moss is bagged and taken away rather than swept into the borders. The softwash treatment: A biocidal treatment is applied at low pressure across the whole roof surface, including ridge and verge, so that what remains is killed at root level. This is the part that determines how long the result lasts. Knocking moss off without treating leaves the holdfasts in place and the roof greens up again quickly, which is why some cleans seem to fail within a year or two. Gutters, valleys and downpipes: Access is already set up, so this is the sensible moment to clear the gutters of the moss and grit that came off the roof, check the valleys are not silted, and confirm the downpipes run. A roof clean that leaves blocked gutters is an unfinished job, and the first heavy rain will make that obvious. What happens over the following weeks: The roof will not be uniformly clean when we leave, and anyone promising that is either pressure washing or overselling. Dead growth greys, loses its grip and washes off progressively with rain and wind. Most roofs look substantially better within a few weeks and continue improving for a couple of months. On heavy lichen a follow-up application is sometimes sensible, and we will tell you at the survey if we think that is likely. Weather and timing: Treatments need dry conditions to dwell rather than being rinsed straight off, so work is planned around the forecast. Spring through autumn is the natural window in Devon, though a settled dry spell in winter works. We would rather move a date than apply in the wrong conditions and produce a poor result. Keeping it clean afterwards: The main things that shorten a roof clean are overhanging branches, blocked gutters holding damp against the lower courses, and a shaded north pitch. Trimming back what you can, keeping the gutters clear annually, and a light maintenance treatment every few years will hold the result far longer than doing nothing and paying for a full clean again.

Questions we get on this

How long until my roof looks clean?: Expect visible change within a few weeks and continued improvement over a couple of months as dead growth weathers off. Heavy lichen takes longest.
Will you walk on my tiles?: We avoid it wherever possible and work from access equipment, because foot traffic cracks older concrete tiles.
Does cleaning damage the tiles?: Softwashing does not. Pressure washing removes the tile's surface layer and can force water under the laps, which is why we do not use it on roofs.
Should I clear the gutters at the same time?: Yes. The access is already in place and the roof debris has to be removed from the gutters anyway.

If this describes your situation

Send a photo of each roof pitch and we will tell you honestly whether it needs cleaning yet.

Send photos for a quote Roof Cleaning Call 07830 242403

Roof cleaning: what actually happens, start to finish