Mixed Reroof in Barrow

The Problem

This 1950s semi in Barrow-in-Furness had been extended in the 1980s with a large single-storey rear addition housing the kitchen and dining room. By the time the homeowner contacted us, both roofing systems had failed simultaneously. The main pitched roof still had its original concrete plain tiles — 70+ years old and severely frost-damaged, with many tiles cracked, porous, and shedding granular debris. The felt underlay was the original bituminous type, torn and perished across most of the roof. The flat roof over the rear extension was covered in three-layer built-up felt that had blistered, cracked, and was letting water through at multiple points, causing extensive ceiling damage in the kitchen and dining room below. The flat roof's timber decking had partially delaminated from prolonged water exposure, and the insulation beneath was saturated and useless. Rather than address each roof separately — which would have meant double the scaffold costs — the homeowner wisely chose to commission both replacements as a single comprehensive project.

Our Solution

We designed a phased programme that kept the property weatherproof throughout. Phase one addressed the flat roof: we stripped all existing felt and delaminated decking, inspected the joists (replacing two that had developed significant rot), installed new 18mm OSB3 decking over tapered insulation boards to create a proper fall, and applied a Firestone RubberGard EPDM membrane in a single sheet with fully bonded adhesion. The EPDM was dressed up the abutment wall and under the first course of tiles on the main roof, creating a weathertight junction. Phase two was the main pitched roof: complete strip and retile with new Redland Grovebury interlocking tiles on breathable membrane and counter-battens. New lead flashings were installed at the chimney and party wall, and a dry fix ridge system with ventilation completed the pitched roof. The critical junction where the flat roof meets the main pitched roof was detailed with a lead apron flashing dressed over the EPDM upstand, creating a belt-and-braces waterproof detail at this vulnerable transition point.

The Result

Both roofing systems are now performing flawlessly. The EPDM flat roof has eliminated the kitchen ceiling leaks completely, and the tapered insulation has solved the ponding water problem that contributed to the old felt's failure. The new pitched tile roof has transformed the property's street appearance, and the dry fix ridge gives a clean, modern finish. The homeowner saved approximately 20% compared to commissioning the two roof replacements separately, primarily through shared scaffold costs and project management efficiencies.

Firestone RubberGard EPDM Membrane

Firestone's RubberGard is a premium EPDM rubber roofing membrane with a proven track record of 50+ year installations worldwide. The 1.14mm thick single-ply membrane is manufactured from ethylene propylene diene monomer rubber, which remains permanently flexible through extreme temperature ranges from -45°C to +130°C. Unlike felt, EPDM never blisters, cracks, or becomes brittle, and its single-sheet application eliminates joints that could potentially fail. The membrane was fully bonded to the insulation substrate using Firestone's own bonding adhesive for maximum wind uplift resistance.

Redland Grovebury Interlocking Tiles

The Grovebury is a modern concrete interlocking tile with a low-profile design that suits 1950s semi-detached properties. Its double-interlock provides excellent weather resistance, and the through-coloured body with Redland's proprietary surface coating resists moss and algae growth. Each tile is mechanically clip-fixed at perimeter and exposed positions in accordance with BS 5534 wind loading calculations for this Barrow location.

Tapered Insulation Boards

PIR (Polyisocyanurate) insulation boards were cut to create a consistent 1:80 fall across the flat roof surface. This achieves two functions simultaneously: providing thermal insulation that meets current Building Regulation standards (achieving a U-value of 0.18 W/m²K), and creating the drainage fall that prevents ponding water — the single biggest cause of flat roof failure.

Code 4 and Code 5 Lead Flashings

Code 5 lead was used for the chimney and party wall flashings, while Code 4 was used for the flat-to-pitched roof junction apron where less thermal movement occurs. All lead work was detailed in accordance with the Lead Sheet Association's technical manual.