Abstract: The present invention relates to a building cavity assembly and, in particular, a building cavity assembly having a thermal break to prevent the development of cold spots acting as a gathering point for condensation. A building assembly comprising an inner and outer skin defining an insulating cavity, a support bar fixedly located in the cavity for mounting the outer skin thereon and an insulating spacer fixedly located between the support bar and the inner skin to provide a thermal break between the inner and outer skins is described. The support bar and the spacer are connected by means of a metal fixing device which passes through at least a part of the support bar and secures it to the spacer and fixes the spacer to the inner skin. The fixing device includes insulating means to insulate it from the support bar and prevent any metal to metal contact therebetween. Methods of use on roof and wall claddings are also described.