Will Roof Cleaning Make a Mess of My Garden?

What actually comes off the roof

The bulk of it is moss, in clumps or in sheets, plus lichen flakes, algae, leaf litter, grit and the odd broken tile fragment. Dead moss is light but often wet and heavy, and when it falls it breaks apart into a green slush that stains paving and clings to shoes. If a roof has not been cleaned for many years, there can be a surprising amount of material in the gutters as well.

The treatment is a separate matter. A biocide is sprayed onto the tiles, and some of it runs down the slope with rain. The amount is small and diluted, but it still needs to be kept away from borders, ponds and vegetable plots. A good contractor plans where it will fall before the work starts.

Old roofs shed in other ways too. Sun-dried moss crumbles into a fine green dust, and small pieces of tile mortar sometimes come loose from the ridge and the verge. These are swept and bagged along with everything else, and any loose pieces are noted for the survey record.

How the garden is protected

Before anyone goes up, we look at what lies beneath the working area. Plants that are close to the wall are covered or watered beforehand, furniture is moved and vulnerable pots are shifted out of the way. Dust sheets or tarpaulins go down on patios and paths, and cars are moved off the drive where there is a risk of overspray or falling debris.

Gutters are lined or cleared in step with the roof, so the moss does not wash into the downpipes and block the drain. Some of this overlaps with the points in our page on roof cleaning run-off and wildlife, which covers where the treatment goes and how ponds and nesting sites are respected.

Where access is tight, such as a terraced house with a narrow side passage, debris is passed down in bags rather than dropped. Roof edges are fitted with a catch where needed. These small steps are what separate a tidy job from one that leaves the garden full of green stains.

Noise, water and neighbours

A hand clean is quiet. There is some brushing and scraping, and the thump of a ladder, but it is not like drilling or a petrol machine. Soft washing uses a small pump. Water is used sparingly compared with a pressure washer, and it does not need a big supply.

Neighbours deserve a word of warning, particularly on terraces and semis where the roofs are joined and the gardens are close. Debris can blow across a boundary on a windy day, and we stop the work if the wind picks up. It helps to tell the next-door household the day before so they can bring in washing. The weather also decides things, which is why we agree a window with you rather than a rigid appointment.

Dogs, cats and small children should be kept indoors or out of the garden while the work is on, because ladders and falling pieces are a risk to them. Bring pets in beforehand and keep them away until surfaces are dry. Our page on whether moss treatments are safe for pets goes into more detail.

What is cleared away at the end

The moss is bagged and taken away, and the beds, paths and drive are swept. The gutters and downpipes are checked for flow. Any covers are removed and the plants uncovered. You should be able to walk around the house afterwards and find nothing you would not have expected to see before we arrived.

If something does go wrong, such as a stain on the patio or a broken pot, tell us on the day so it can be put right. The survey is the place to raise worries about particular plants, a pond or a greenhouse. We note them in the plan, and the fixed written quote makes clear what is included. The full list of what the service involves is on our roof cleaning in Basingstoke page.

Most gardens look better than before once the roof is clean, since the moss that used to fall into them has gone.

If you keep a compost heap or a wormery near the house, tell us, because treated moss should not go in it and we bag it separately. Greenhouses and cold frames beneath a roof edge are covered with sheeting for the day.