This paper deals with the mechanical and fire behaviour of simple solutions of thermal breaks for external steel structures (balconies, passageways, solar panels …) attached on a concrete facade with external thermal insulation. The proposed solutions are composed of a PVC or plywood layer implemented between an extended end-plate connection and the concrete support (lintel, floor slab, concrete wall). A total of 12 monotonic mechanical tests have been performed on steel-to-concrete connections using intermediate insulation layers (PVC or plywood) in order to investigate the rotational stiffness, plastic/ultimate bending moments, the rotation capacity as well as the failure mode. Two types of fastening were used; bolted embedded end-plates and post-installed mechanical/chemical fasteners. In order to evaluate the influence of the studied solutions of thermal breaks on the behaviour of a balcony under fire, two external flame experimental tests were carried out on realistic balconies attached to a concrete support. These fire tests demonstrated that the implementation of the proposed thermal breaks between end-plates and the support does not affect the stability of the balconies subjected to fire. © 2021