The project

The replacement bus station and regeneration of the surrounding area has created a unique and distinctive city centre building for the town.  The design connects with Gloucester’s Roman heritage and association with aviation.

The brief

The innovative roof design incorporated a canopy intended to reflect an aircraft wing that required a lightweight waterproofing and renewable energy photovoltaic (PV) solution.
 
The Bauder single ply Thermofol PVC waterproofing system with the BauderSOLAR PV solution met the brief precisely without compromising the aesthetics of the roof. The installation required constant co-operation and communication to embrace the live site operations within the restricted city centre location whilst allowing the bus station to remain fully functional. The roofing contractor delivered a superior standard solution and  any complex issues that arose during the project were resolved promptly and collaboratively.

Bauder Building Board

Project: Gloucester Bus Station
Location: Gloucester
Roof Size: 1520m²
Constructor:  Kier Group Plc
Approved Contractor: Kovara Projects Ltd

The systems

This combination of  Thermofol PVC single ply waterproofing system and BauderSOLAR PV delivered a high quality, strong, energy efficient flat roof.
 
Our Thermofol PVC membrane with a formulation of high grade virgin polymer and superior fire retardants ensuring optimum membrane characteristics to deliver high performance and a BBA stated life expectancy in excess of 35 years. The system is suitable for use with BauderSOLAR PV and the assembly employed is FM Approved. 
 
BauderSOLAR PV for flat roofs is an aerodynamically optimised system for framed modules and the mounting units are secured to the roof using membrane-to-membrane welding techniques. This installation method means that the roof is not compromised by penetrations of fasteners nor is it ballasted.

Challenges

The design of the Transport Hub and city centre location proved to be the key challenge to this project. The unusual roof configuration required a bespoke insulation scheme using Bauder PIR FA, an extremely efficient rebated PIR insulation board with aluminium foil facing on both sides, in order to achieve the required U-value of 0.18W/M²K. The deck configuration equally made the installation of the Bauder Thermofol PVC waterproofing system complex with the perimeter zone having to be carefully marked in compatability the wind calculation which included measuring factors such as wind speed, altitude, direction and exposure. Bauder and Kovara Projects were required to work closely together to ensure all criteria of the wind calculations were met. 40 modules of the lightweight BauderSOLAR PV solution were installed on the west side of the Transport Hub’s roof.

The installation

The OMG Rhinobond induction welding system was specified as the installation method which provided multiple advantages to the project, not only saving time and fasteners, but also optimising the field fix pattern of installation and ensuring that the load on the roof was spread between the induction welding plates.

The location of the project, Gloucester city centre, presented logistical challenges. Delivery of the roofing products had to be carefully scheduled and managed to avoid creating congestion in the area.

Applied products

Thermofol PVC single ply 

This system was selected for the project because of its lightweight properties which complemented the deck and roof design. Light grey was chosen to reflect the colour of the cladding as the aesthetics was a key objective for the client.

 

Bauder Thermofol PVC U15 membrane This reinforced, mechanically fixed PVC membrane was chosen because of its fast-track, torch free installation, and to accompany the BauderSOLAR system.
PIR FA Insulation 120mm Our Bauder PIR FA Insulation is a rigid urethane foam insulation faced on both sides with aluminium foil. This project used 120mm depth to meet the required U-value of 0.18W/M²K.
DB100 Polyethylene air and vapour control layer installed by loose laying used for its suitability for the Thermofol mechanically fastened single ply system. .