Roof cleaning and moss removal

Moss on a roof looks worse than it usually is in the early stages, but left long enough it becomes a genuine problem: it holds moisture against the tile surface, works its way under the edges, and sheds constantly into the gutters below, blocking them and sending the whole cycle backward into an overflow problem. Roof moss removal, done properly and without stopping it coming straight back, is a specific skill, not a generic pressure wash.

Why we do not pressure wash roofs

High pressure jet washing strips the granule coating off concrete tiles and can force water up under the tile laps, straight into the roof structure it is supposed to be cleaning. We do not do it. Moss and lichen come off with careful manual removal and low pressure treatment that cleans the surface without damaging it or pushing water where it should not go.

What the job actually involves

• Manual removal of moss and lichen from the tile or slate surface
• Low pressure cleaning of the remaining growth and staining
• Clearing everything that comes off out of the valleys and gutters, not left to wash down and block them
• A biocide treatment applied afterward to slow regrowth
• A check of the tiles underneath the moss for any damage it may have been hiding

What we do differently to a generic cleaning firm

A general exterior cleaning company can jet wash a driveway and a roof with the same equipment and the same approach, and that is exactly the problem. A roof needs someone who understands tile and slate fixings, valleys, and how water moves once it is on the roof surface, so that cleaning it does not create a new leak in the process of removing an old cosmetic issue. We approach it as roofing work, because it is.

Why moss builds up in the first place

North facing slopes, roofs shaded by trees, and older, more porous concrete tiles all encourage moss growth. It is not usually a sign anything is wrong with the roof itself, but ignored long enough it can lift tiles slightly and hold enough water to accelerate their wear. We will tell you honestly whether your roof needs cleaning now or can wait.

What comes with the clean

Because we are already on the roof, we check the tiles, ridge and valleys underneath the growth and flag anything found, with photographs, at no extra charge. Gutters get checked too since moss debris is one of the most common causes of a blocked run, see our gutter cleaning page.

How long the result lasts

A biocide treatment slows regrowth significantly, but it does not stop moss forming permanently, particularly on a shaded, north facing slope where the conditions that caused it in the first place have not changed. Most properties see a genuinely long gap before moss becomes noticeable again, and we will tell you honestly what to expect for your specific roof rather than promise it will never return.

Lichen is a different problem to moss

Lichen, the crusty yellow, grey or white patches sometimes seen on older tiles, is a different organism to moss and behaves differently, it grows much more slowly and is generally less harmful to the tile surface, though heavy lichen cover can still trap moisture in the same way. We treat it as part of the same clean where present, using an appropriate method rather than the same approach used for thicker moss growth.

Trees and overhanging branches

If overhanging branches are feeding constant leaf litter and shade onto a roof slope, cutting back or removing that growth, where it is your own tree and safe to do so, makes a genuine difference to how quickly moss returns. We will point this out honestly if it is the main driver behind a heavy moss problem, since no amount of cleaning permanently fixes a roof that is shaded and showered in leaf debris every autumn.

Zinc and copper strips

On some roofs, a thin strip of zinc or copper fixed near the ridge slowly releases trace amounts of metal ions as rain washes over it, which inhibits moss growth on the slope below over time. It is not a substitute for cleaning an already established growth, but it is worth discussing as a longer term measure on a roof that suffers from moss repeatedly despite regular cleaning.

Areas we cover

Roof cleaning and moss removal across Wisbech, Norwich, Cambridge, Huntingdon and the rest of Cambridgeshire, Norfolk, west Suffolk and south Lincolnshire. See our roof cleaning cost guide for typical pricing.