Insulation and cladding rail system

A three part rail and link system for the attachment of thermal insulation to existing buildings comprises a rail 1 that is attached to the building substrate (b), a sliding link piece 2 that engages in the attachment rail 1 and a connecting rail 3, included in the insulation material (d), extending almost to the surface of the material. This allows insulation to be attached to the building but creates a continuous link from the original substrate to the exterior face of the insulation to enable a facade to be fastened to it to mechanically tie into the existing building. The sliding link piece creates a cavity between the building substrate and the insulation. The connecting sliding link is sectional with sections arranged end to end and having overlapping end formations. Each section has either parallel flanges or an asymmetrical shape such that the depth of the section, and so the gap between the substrate and insulation, varies along its length. This allows accommodation of variation in the substrate to which the attachment rail is fixed.