How Long Does Roof Cleaning Take?

What decides how long the job takes

Size is the first factor, but it is not the only one. A plain gable roof is quick to work across. A roof with dormers, valleys, a chimney and a rear extension has far more edges to brush and more places where moss collects. The thickness of the growth matters as well, because deep, dense moss has to be lifted and cleared before anything can be sprayed, while a light film of algae can be treated directly.

Access counts for more than people expect. A roof you can reach from a ladder or from a low scaffold is a quicker job than one on a three-storey house, or one with a flat extension in the way. If the slope cannot be reached safely without extra equipment, that is arranged before the work begins. Our page on whether roof cleaning needs scaffolding explains when it is and is not required.

Chimneys, roof lights and solar panels slow things down as well. Each one needs brushing around by hand, and lead flashings must not be scraped or caught. Where a roof has a satellite dish, an aerial or a run of cables, those are worked around rather than moved. A roof with a lot of such details takes longer than a clean, bare slope of the same area, and the survey is where we count them.

How the work is ordered on the day

It starts at the ridge and works down, so that debris and treatment run onto surfaces still to be done. Loose moss is brushed or scraped off by hand, then collected rather than allowed to wash into the gutters. Gutters and valleys are cleared as part of the same visit, because moss that has dropped into them is the usual cause of an overflow.

Once the slope is clear, a biocide is applied across the tiles so that anything left in the pores of the surface is killed. The ground and beds below are protected throughout, and the site is left clear at the end. If the roof is large, the job is often split across two days so that nothing is rushed at the end of the light. On the roof cleaning safety page we explain how we keep both the crew and your garden safe.

Gutter work is the other part that is easy to underestimate. Moss that has fallen from the roof tends to sit as a sodden mass in the run, and it has to be lifted out by hand and bagged. Downpipes are checked to see that water can leave freely. Doing this as part of the same visit saves a second trip, and it means the roof is left properly draining rather than half done.

Weather and timing

Rain does not just slow the work, it makes a roof slippery and spoils the treatment, which needs a dry spell to bond. A wet day usually means a postponement. Strong wind is another reason to stop, because the spray drifts and loose debris blows about. A reasonable window in spring or autumn often suits the job. Our answer on the best time to remove roof moss goes into the seasons in more detail.

Building the weather into the plan is why we give a window rather than a promise to the hour. We agree a date with you at the survey and tell you straight away if the forecast changes it.

What happens after we leave

A treated roof does not look finished the moment the crew packs up. The biocide works over the following weeks. Dead moss and algae loosen, and the rain and wind bring them off the tiles gradually. In many cases the roof looks cleaner and cleaner over the next few months. This is normal, and a sign that the treatment has taken hold.

The free survey comes first, with photos taken on your roof, which show the growth and the state of the tiles, and a fixed written quote follows. Typical UK ranges for hand removal with biocide run from about £748 for a small roof to about £978 for a large one, and the final figure is fixed in writing after we have been up and looked. If a roof clean would not help because the tiles are failing, we say that before you spend anything. You can read about the whole service on our page for roof cleaning in Basingstoke.

If you want a clear idea of the schedule, ask at the survey. We can tell you how many days we expect to be on site, which part of the garden we will need to use, and what we would do if the weather turns. A plain agreement beforehand is better than a surprise on the day.