A solicitor approached RAH Consultancy with regard to the presumed failure of design in a underfloor heating system. Our work entailed a site inspection during which we investigated the nature and thickness of the floor finish on top of the underfloor heating. The heating system comprised five zones which it was claimed were inadequately designed.Our investigations included studying the relevant standards and evaluating the heating requirements so as to establish the correct design parameters needed. Our advice was that although the workmanship of the installation was questionable the installation had been correctly designed but the efficacy of the heat output had been compromised by the addition of carpet and underlay subsequently placed on top of the wood flooring.