Roof Moss & Algae Removal in Northern Ireland

If your roof has turned green, you are far from alone. Moss and algae thrive on roofs right across Northern Ireland. RoofersNI connects homeowners with fully insured local roofers who safely clean roofs and treat them to keep moss at bay.

Moss loves damp, shady conditions, and Northern Ireland's mild, wet climate provides exactly that for most of the year. North facing slopes, roofs under trees and porous concrete tiles that hold moisture are particularly prone to heavy growth.

Moss acts like a sponge, holding water against your roof. It grows into the gaps between tiles, lifting them and allowing rain to be driven underneath. In winter that trapped water can freeze, cracking tiles. Clumps of moss also wash down into gutters and downpipes, causing blockages and overflows.

Pressure washing can damage tiles and force water under them, so many roofers now prefer a soft wash approach. Moss is carefully scraped off by hand, then a specialist biocide is applied at low pressure to kill remaining moss, algae and lichen down to the roots. The roof continues to clean itself over the following weeks.

A follow up biocide treatment every couple of years helps prevent regrowth. Clearing gutters at the same time keeps water flowing freely.

In Belfast, concrete tiled roofs on 1960s and 1970s estates are among the worst affected. In Lisburn, homes under mature trees are especially prone to heavy moss. Send us a WhatsApp with your area and a photo of the roof.