Gaco Asbestos Roof Waterproofing in Derry — Encapsulation Without Removal

Derry/Londonderry had 84,884 residents in Census 2021, counted across both banks of the River Foyle, and it lies only a few kilometres from the border with Co. Donegal. Derry City and Strabane District Council is the local authority. Around the city sit smaller settlements such as Eglinton, Newbuildings, Culmore, Strathfoyle and Claudy, where the built-up area gives way to farmland.

The city’s working buildings are varied. Just downstream, Foyle Port runs its deep-water bulk terminal at Lisahally, and across the council area there are stores, workshops, public buildings and farm outbuildings of many different ages. Where any of them still carry corrugated asbestos cement, the sheets are likely to be decades old. If a roof is leaking and nobody is sure what it is made of, identifying the material has to come before any repair, because asbestos cement must not simply be cut, drilled or pressure-washed.

Derry’s weather is defined by frequency. The Met Office’s Ballykelly station in Co. Londonderry averaged about 861 mm of rain over 1991 to 2020, with around 176 wet days a year. Rain that frequent keeps asbestos cement damp for much of the year, and the sheets respond by growing moss, losing their surface and cracking around fixings. For anyone coating a roof it also means fewer dry days to work with, so preparation is organised to make the most of each dry spell when it comes.

Encapsulation seals the sheets in place instead of removing them. The approved installer carries out a condition survey, replaces any sheets that are broken, and cleans the roof by a non-abrasive method before applying Gaco urethane coatings. Access is from crawling boards and staging, never from the sheets themselves. Because nothing is stripped, a store or workshop can generally stay in use, subject to the installer’s risk assessment for each section. Duratite supplies the coatings and refers Derry enquiries to an approved installer covering the north-west.

Being so close to the border, it is worth being clear about which rules apply. In the city and its villages, the Control of Asbestos Regulations (Northern Ireland) 2012 govern the work and HSENI is the regulator. A building a short drive away in Co. Donegal falls under the Republic’s own asbestos regulations and the Health and Safety Authority instead, so owners with property on both sides should expect each site to be planned under its own rules. Derry City and Strabane District Council is the building control contact if insulation forms part of the job under the Building Regulations (Northern Ireland) 2012 and Technical Booklet F2. The island-of-Ireland reference project is SAICA Warrenpoint, Co. Down.