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Solar PV Flex

Solar PV Flex

Solar PV Flex is our lightweight thin film alternative to traditional photovoltaic arrays. This innovative technology is ideal for lightweight deck types, curved roofs and sites with planning constraints. Bonded on our Excel® Solar membrane, this is an innovative solution for refurbishment and new build projects.

It is a unique integrated solution that provides robust, durable bitumen waterproofing and the production of clean efficient electrical energy within a single flat roof system configuration.

Solar PV Flex combines Excel® high-performance reinforced bitumen waterproofing membranes, manufactured with the patented Alpa® polymeric binder with fully bonded Solar PV Flex (CIGS) modules.


Solar PV Flex is a flexible polymer encapsulated thin-film solar module based on advanced CIGS (Copper Indium Gallium Selenide) technology. The photovoltaic modules are lightweight (2.9 kg/m²), shatterproof, hail resistant, compatible with Excel® Solar bitumen waterproofing membrane and, being flexible, are suitable for all roof shapes with no requirement for orientation, plinths, or ventilation. Increased energy output is achieved when compared to rigid panel systems in low level light or indirect light conditions.

The Solar PV Flex with an Excel® waterproofing system is designed for installation in either a multi or single layer application using torch-on techniques. With exceptional ageing characteristics and excellent bond strength, Axter's Solar PV Flex has been technologically developed to be flexible and durable and is suitable for use on all new build and refurbishment Solar PV projects.

Design and Installation

The application technique for Solar PV Flex eliminates any need for penetration of the Excel® waterproofing system during installation and greatly simplifies installation on roofs of all shapes and sizes. The modules can simply be bonded to curved surfaces, enabling solar power generation on roofs where traditional rigid silicon panels are not suitable.

Prefabricated cable penetration units should also be installed to ensure the waterproofing system integrity is maintained at all times.

We will offer a full bespoke design pack including a 3D model covering the yield calculation, wind uplift calculation (where required) and a modelled output of the system. We can also show you an accurate cost saving if we are provided with the consumption figures.

We will supply you with a full system, which includes the recommendation of an approved Axter installation partner.

Product Warranty and System Guarantee

The CIGS module carries a 5 year product warranty against material defect and a 25 year linear power output warranty - 80% of the nominal power (STC). As part of a BIPV (Building Integrated Photovoltaic) system, please see the waterproofing product guarantee documents for the full guarantee information.


Solar PV Flex waterproofing system is British Board of Agrément (BBA) certified Certificate No 94/3037, compliant with BS 6229: 2018 - Flat Roofs with continuously supported flexible waterproof coverings – Code of Practice, CE Marked and accepted by all third-party building warranty providers such as the LABC and the NHBC, and B Roof (T4) tested.

More Benefits

  • No roof penetrations BIPV solution
  • Shade tolerant CIGS technology
  • Can be installed on curved surfaces not suitable for rigid panels
  • Lightweight, less than 2.9kg/m2 (6.2kg/module)
  • Excellent bond strength
  • Multi-layer or single layer waterproofing options
  • Approved for all structural deck types (concrete, metal, timber)
  • Suitable for new build and refurbishment projects

Excel Solar PV Flex Warm Roof Single Layer

A unique single layer waterproofing system with an integrated and lightweight CIGS photovoltaic module finish. Maximises roof usage while minimising risk.

Excel Solar PV Flex Warm Roof Multi-Layer

A unique multi-layer waterproofing system with an integrated and lightweight CIGS photovoltaic module finish. Maximises roof usage while minimising risk.


Technical Datasheet
Product Datasheet
Declaration of Performance
Material Safety Datasheet

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