Roxy Lanes, Union Street, Bristol
Client: MAPP Building Consultancy
Project Overview
Roxy Lanes, Union Street, Bristol
1,700 m²
Service: Roofing
Sector: Retail & Leisure
- Approved Contractor: MLG UK Ltd
- System Installed: Polyroof Protec liquid system
- Client: MAPP Building Consultancy
- Duration: 6 months, over a venue that stayed open throughout
- Work Carried Out: Strip-out, thermal upgrade, liquid waterproofing over an operational venue
Scope of Work
Water had saturated the insulation across 1,700 m² of roof at Roxy Lanes and was beginning to threaten the structure below. The failing Trocal single-ply membrane was replaced, working with Polyroof, with a substantial thermal upgrade built into the new system.
- 1,700 m² of failing Trocal PVC single-ply membrane replaced
- Polyroof Protec liquid system: continuous, joint-free membrane with no weak points
- 130mm Polyroof Tissue-Therm insulation, achieving a U-value of 0.18 W/m²K
- Installed by MLG’s in-house roofing team with weekly inspections by Polyroof’s technical team
Systems installed
- Waterproofing: Protec liquid system: full built-up scheme, stripped back to the original metal deck (Polyroof), 25 yr guarantee
- Insulation: 130mm Tissue-Therm built-up system (Polyroof)
- Walkways: Polygrip anti-slip walkways installed on completion (Polyroof)
Challenges & Constraints
Extensive active leaks
Active leaks were found on starting. Water had saturated the insulation across 1,700 m² of roof and was beginning to threaten the structure below.
A six-month-old floor below
A bowling alley installed only six months earlier sat directly beneath the roof, so the water had to be stopped immediately rather than at the end of the programme.
Open, and weather-bound
The venue stayed open and trading throughout, and unpredictable weather gave only intermittent working windows.
Project Execution & Techniques
Leaks stopped first
Immediate action was taken on the active leaks to protect the bowling alley below before the main works proceeded.
Back to the deck
The failing Trocal PVC single-ply membrane was removed and the Protec built-up scheme installed back to the original metal deck.
Thermal upgrade built in
130mm of Polyroof Tissue-Therm insulation was built into the new system, taking the roof to a U-value of 0.18 W/m²K.
Weekly Polyroof inspections
Polyroof’s technical team inspected the work weekly, so compliance with the manufacturer specification was externally evidenced rather than self-declared. Installation was by MLG’s own in-house roofing team.
Outcome & Long-Term Benefits
A joint-free membrane
The liquid system gives a continuous membrane with no laps or seams to fail, which suited a roof that had failed at its joints.
A warmer roof
The thermal upgrade to 0.18 W/m²K cuts energy use and reduces condensation risk.
Twenty-five year guarantee
The Polyroof Protec scheme carries a 25-year guarantee.
Open throughout
1,700 m² was delivered over a venue that stayed open and trading for the whole programme.
Conclusion
Roxy Lanes had two problems at once: 1,700 m² of saturated insulation under a failing single-ply membrane, and a bowling alley fitted six months earlier sitting directly underneath it. Stopping the water could not wait for the end of the job, and the venue was not closing.
MLG stopped the active leaks first, then stripped back to the metal deck and installed the Polyroof Protec system with 130mm of Tissue-Therm insulation, reaching a U-value of 0.18 W/m²K. Polygrip anti-slip walkways went in on completion. Polyroof’s technical team inspected weekly, and the finished roof carries a 25-year guarantee.
"The MLG roofing team consistently combine technical expertise, reliability and genuine care for the client's needs. Their attention to detail, proactive communication and commitment to quality make them a standout in the industry, whether it's a minor repair or a full-scale replacement, they approach every project with professionalism and pride, and never drop their health and safety standards."
, Lee Husband MRICS, Director, Head of Building Consultancy, MAPP
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