Gaco Asbestos Roof Waterproofing in County Londonderry — Encapsulation Without Removal

Historic County Londonderry runs from Lough Foyle and the Atlantic in the north-west to the River Bann in the east. It is no longer one administrative area: Derry City and Strabane District Council covers most of it, Causeway Coast and Glens takes the north and a small eastern part lies in Mid Ulster. Outside the city, the county’s towns include Coleraine, Limavady, Magherafelt, Dungiven and Kilrea, each serving a wide farming hinterland.

Grass defines that hinterland. DAERA’s 2025 census recorded 158,709 hectares farmed under Co. Londonderry addresses, and 113,581 hectares of it was grassland. The 3,483 farms average 35 hectares and carry 208,647 cattle, including 41,855 dairy cows, alongside 364,620 sheep, the second-largest county flock in Northern Ireland, with 175,143 breeding ewes. Lambing sheds, cattle housing, fodder stores and machinery sheds are the working buildings of this kind of farming, and many are used hardest in winter and early spring, which is exactly when a leaking roof does the most harm.

Rain here arrives often rather than heavily. The Met Office’s Ballykelly station averaged about 861 mm a year over 1991 to 2020, which is not an extreme total, but it fell on around 176 wet days, more than at Aldergrove or Armagh. A roof that is wet on nearly half the days of the year rarely dries out properly. On asbestos cement, that persistent dampness encourages moss and lichen, softens the face of the sheet and works at fixings and laps until leaks appear, often over the bays where they are least welcome.

Encapsulating the roof keeps the sheets in place and seals them. The approved installer first surveys the sheets and the frame, replaces any that are cracked through, and removes growth by a non-abrasive method, before the surface is sealed with Gaco urethane coatings. The number of wet days shapes the programme: coating needs a dry surface and conditions within Gaco’s published limits, so a big roof on a Limavady or Magherafelt farm may be done in sections as dry spells allow. Duratite supplies the coatings and refers County Londonderry customers to an approved installer.

Bulk animal feed and fertiliser come into the north-west through Foyle Port at Lisahally, which handles around 2 million tonnes of cargo a year and supports roughly 1,000 direct and indirect jobs, and a sound roof keeps those materials usable once they reach a farm store. Across the county, asbestos work comes under the Control of Asbestos Regulations (Northern Ireland) 2012, enforced by HSENI, and the installer produces a risk assessment and plan of work before starting. If insulation is added, Technical Booklet F2 under the Building Regulations (Northern Ireland) 2012 applies, handled by whichever of the three councils covers the site. The island-of-Ireland reference project is SAICA Warrenpoint, Co. Down.