CABI Case Study

The project

The Centre for Agricultural and Biosciences International (CABI) is an inter-governmental, not-for-profit organization that improves people’s lives worldwide by providing information and applying scientific expertise to solve problems in agriculture and the environment.

His Royal Highness the Prince of Wales opened the old CABI headquarters in September 1987. Over time, the former school building had become outdated and was no longer fit for purpose, being uneconomical in terms of layout and energy efficiency, and required a high level of maintenance.

Bauder Building Board

Project: Centre for Agricultural and Biosciences International (CABI)
Location: Wallingford, Oxfordshire
Project type: New build
Roof size: 2044m²
Specifier: Scott Brownrigg
Main contractor: Barnwood Construction
Approved contractor: Malone Roofing

The specification

The client’s objective for the new headquarters was to construct an eco-building that made a statement, whilst also blending into the surrounding countryside.

For the roof, Bauder’s lightweight Thermofol PVC waterproofing was specified with an extensive sedum blanket to create a green roof. Rooflights were incorporated to provide natural top light, helping to reduce demand for electric lighting and help lower CO2 emissions.

The technical and sustainability expertise and support available from the Bauder technical team and area manager, coupled with the comprehensive guarantee package made Bauder the ideal supplier to work with the architects on this project.


Products applied

Bauder Thermofol PVC
This single ply system is lightweight and has a high-grade virgin polymer formulation with superior fire retardants. The PVC formulation ensures it is resistant to chemicals and micro-organism attack making it well suited to receive a green roof.

BauderPIR FA Insulation
To achieve efficient drainage and taking into consideration the shape of the roof, BauderPIR FA Insulation was specified on the CABI project. This insulation is lightweight, cost effective and easy to install. The low thermal conductivity allows for the insulation to be of reduced thickness compared to other insulants and the layout scheme is designed to produce minimal waste.

Bauder XF301 Sedum Blanket 
Bauder’s XF301 Sedum Blanket is a mature vegetation blanket, sown with a variety of sedums. It is intended for application directly over the waterproofing system without the need for a secondary substrate growing medium, making it the lightest self-contained sedum blanket system available.

Project challenges

The curve of the roof, which at some points reached a pitch of over 30 degrees, posed a number of challenges. Firstly, we had to ensure that the roofing contractors could safely install the Bauder system to the required standard, even with the extreme pitch. To meet this challenge, retaining battens were used where the pitch was at its steepest. When fixing the battens to the metal deck, there had to be a sufficient bond to the deck to ensure adequate attachment. With the deck exposed below, mechanical fixings had to be used sparingly so that they were not seen. The curve of the roof also had to be factored into the fixing of the sedum blanket. Retention strips were added to the design to hold the sedum in place securely and prevent any slippage. These were spaced at a 1m distance to ensure a strong and secure install.  The ongoing maintenance of the roof will be facilitated by the access walkways and safety systems that will remain in-situ, providing safe access for watering, fertilisation, and general maintenance.


The result

CABI’s new office building demonstrates striking architecture by Scott Brownrigg Architects. In keeping with CABI’s role as an environmentally concerned organisation, the building will perform to a very high level of sustainability. The offices will provide a modern, comfortable, and efficient working environment and a number of facilities available for use by the local community.


System installed

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1 Bauder XF301 Sedum Blanket Bauder’s XF301 Sedum Blanket is sown with 11 different species. As the sedum adjusts to the project location, the plants most suited to the climate will flourish, blending the roof naturally into the surroundings as per the client’s specification
2 SDF Mat Drainage/Filtration Layer The SDF mat is a multi-functional drainage and filter layer which prevents the roots of the plants in the XF301 sedum system from becoming waterlogged.
3 Sedum Blanket Retention Strip Sedum Blanket Retention Strip is a stainless-steel strip that mechanically prevents slippage of the blanket. They are supplied with a protective plastic cover.
4 Bauder Thermofol U15 FB Membrane Thermofol U15 Fleece-Backed Membrane is a 1.5mm polyester reinforced Poly Vinyl Chloride membrane (PVC). The membrane has internal plasticizers incorporated during the manufacturing process and a polyester fleece underside. This combination of
materials give high tensile strength, good thermal stability, chemical resistance, and flexibility.
5 BauderPIR FA Insulation BauderPIR FA Insulation is a highly efficient insulation manufactured in various thicknesses.
6 BauderTEC KSD Mica Air and Vapour Control Layer A technically advanced, robust, self-adhesive SBS elastomeric bitumen air & vapour control layer, with a mica finished upper surface to allow easy bonding of insulation using the specified Bauder Insulation Adhesive.