Radflex 125 A1: Download Data Sheet

General Expansion Joint

The Radflex 125 system provides a durable and versatile permanent joint, which is easily installed and maintenance-free. Capable of accommodating a wide range of conditions, it is equally effective on an asphalt-covered, traffic-free roof or a bridge deck. It can be used in conjunction with most waterproofing systems.A specially developed butyl rubber compound ensures the Radflex 125 membrane is tough and weatherproof as well as highly flexible, capable of withstanding up to 300% elongation. The 125 system comprises the original Radflex single laminate with its inherent strength and excellent bonding properties for surface applications; and a double laminate version for use where enhanced linkage to other waterproofing systems is required.

S125-3DEpoxy Adhesive

Radflex epoxy adhesive has been formulated for highly effective bonding of the rubber membrane to concrete, asphalt and other substrates, creating a 100% waterproof seal between the substrate and membrane. The result is a continuous watertight finish throughout the structure.

Radflex 125 is registered with the Highways Agency and is approved for use as a buried joint on bridge structures.
Simple, proven design and high quality manufacturing components combine to provide an ideal core solution for general expansion joint applications.

Materials Performance

The component parts of the system are non-degradable, unaffected by UV light or ozone and completely impervious to water or water vapour. In buried joints, the 125 membrane is totally protected by the wearing surface and its long-lasting properties ensure the system will not degrade or crack in service. Robust materials, straightforward installation and proven high performance meet the exacting standards of the modern construction industry.

Health and Safety

Installation and use causes no ‘health and safety at work’ hazards, provided that manufacturers’ instructions are followed regarding the use of adhesives and sealants.


Concrete surfaces must be float finished, abraded to remove laitence and provide good bonding substrate. If the concrete surface is unsound, it should be made good with polymer modified mortar, in accordance with manufacturers’ instructions. The concrete shoulders must be smooth and level across the expansion gap. We do not recommend application to lightweight or sand and cement screed.

Mastic asphalt surfaces to which the Radflex membrane is to be bonded must be well sand-rubbed to remove nibs and excess bitumen fat to give a clean, flat surface free from surplus sand. The surface should be smooth and level across the joint.

Reference Installations

Radflex systems are installed in many different conditions in a variety of climates. We are pleased to refer enquirers to relevant applications to confirm satisfaction with the installation and system performance.

Radflex Design Services

Advice and design services are available from our Technical Department, including reviewing requirements, providing detailed drawings and ensuring installation of the most appropriate Radflex system to suit specific sites.

Columns, Walls, Kerbs and Corners

Continuity of the waterproof seal is ensured by bonding the Radflex membrane to the surface of the horizontal asphalt/concrete and to the face of skirting asphalt/concrete.  Internal and external corners can be easily accommodated.

s125diagramTechnical Specification

Radflex 125 DLM/SLM x __mm wide bonded with Radflex epoxy adhesive, ___ LM horizontal/vertical/angle with __ no. termination details and __ no. changes in direction.  Supplied and installed by Radflex Contract Services Ltd. (Tel: 01322 276363 / 0191 417 6677).


Radflex is a registered trade mark. The Radflex 125 system is the subject of UK Patent 1288314. All reasonable care has been exercised in preparing this data sheet, which to the best of our knowledge is true and accurate.  Due to our programme of continuous improvement, the specification may be subject to updating.