8,400m² Industrial Flat Roof Liquid Waterproofing, Rotherham

The Challenge

A South Yorkshire metal stamping plant operated 24/7 from a 1980s-built facility comprising five interconnecting flat-roof bays totalling 8,400m². The original built-up bituminous felt had reached the end of its service life, with more than 30 individual leaks reported across a single quarter and water damage developing on production line equipment below.

A conventional strip-and-replace re-roof was quoted by another contractor at over £680,000 and would have required the affected bays to be taken out of service in turn, unacceptable in a plant running continuous shifts to meet automotive sector contracts. The client needed a system that would restore weathertight performance without the disposal cost, fire risk or shutdown time of a traditional re-roof.

Our Approach

Our technical team carried out a full close-quarters condition survey, identifying that the underlying felt remained mechanically sound and could serve as a substrate for an overlay. We specified a cold-applied, fleece-reinforced PMMA liquid system applied directly over the existing membrane, avoiding strip-out entirely.

Works were sequenced into nine working zones, with each zone surveyed, prepared, primed, base-coated, fleece-embedded and topcoated within a single working window. Detailing around 47 rooflights, 12 mechanical plant penetrations and 3,800 linear metres of upstands was carried out by hand, with all metal flashings cleaned and coated to integrate seamlessly with the new membrane.

Because the system is cold-applied and emits no fumes during cure, all works proceeded with the plant fully operational below. A directly employed crew of six technicians worked Monday to Friday days, with no out-of-hours premium and no impact on shift patterns.

The Result

The roof has been fully weathertight since handover in September 2025, with zero leaks reported in 14 months of continuous service. The client estimates avoided downtime savings of £180,000 against the originally proposed strip-and-replace programme, in addition to a project cost saving of approximately £390,000.

A 20-year guarantee covers the full 8,400m². The client has since contracted us to deliver a planned cut edge corrosion treatment programme on the adjoining metal-clad warehouse, demonstrated by the success of this initial overlay project.

Services Used on This Project