Moss holds water
A cushion of moss acts like a sponge. After rain it stays wet long after the rest of the roof has dried, keeping the tiles beneath it damp. That constant moisture is what allows algae and lichen to spread too, and on porous concrete tiles it means the surface spends much more of its life wet.
Frost and freeze-thaw
When water held in moss and in the surface of a tile freezes, it expands. Repeated over many winters, that freeze-thaw cycle can contribute to surface wear on older tiles. Removing the moss means the roof can drain and dry more like it was designed to.
Lifted tiles and blocked gaps
Moss often grows thickest in the gaps where tiles overlap. As it builds up, it can lift the edges of tiles and hold them slightly apart, which can let wind-driven rain get underneath. It also grows into valleys and around chimney flashings, places where water needs to flow freely.
Gutters and downpipes
This is the problem most homeowners notice first. Rain washes loose moss off the roof and into the gutters, where it combines with leaves into thick silt. Blocked gutters overflow, staining walls, soaking the ground beside the house and potentially contributing to damp. Clearing gutters helps, but if the roof is still covered in moss the gutters will fill up again.
- ✓Moss clumps on the ground after wind or rain
- ✓Overflowing gutters in heavy rain
- ✓Thick moss along the bottom courses of tiles
- ✓Tiles that look lifted or out of line
- ✓Green or dark staining on walls under the gutters
When moss is mainly cosmetic
A thin scattering of moss, or a few small patches on an otherwise sound roof, is mostly a question of appearance. There is no need to rush. Keep an eye on it each year and act when it starts to build up along the lower edges or in valleys.
Removing moss safely
How moss is removed matters as much as removing it. Walking on tiles or blasting them with high pressure can do more harm than the moss itself. Our main method is the air pole, used from ground level or a ladder, with a biocide treatment available afterwards. If we see broken or slipped tiles, we will tell you so you can have them looked at by a roofer.
Frequently asked questions
Will moss make my roof leak?
Not on its own overnight, but heavy moss can lift tiles and block water paths, which over time can let water in where it should not.
Is a small amount of moss a problem?
Light patches are mainly cosmetic. Keep an eye on them and act when growth thickens.
Can I just scrape it off myself?
Working at height is risky and walking on tiles can crack them. We recommend using a professional with suitable equipment.
Do you repair tiles?
No. We clean roofs and will point out any tiles that look damaged so you can contact a roofer.
Will removing moss stop it coming back?
Moss regrows over time, but a biocide treatment after cleaning helps slow it down.