If you want your underfloor heating installed in the concrete slab of your new build or extension, it needs to be designed at the drawing stage. The slab's thickness must be increased to accommodate the piping. Sometimes builders think they know the requirements but actually don't, resulting in the client not getting the underfloor heating they wanted. We have been called in several times after the slab has been poured, only to find insufficient depth for an in-screed (rather than in-slab) installation, making underfloor heating installation impossible. Please call for more information if you are considering in-slab underfloor heating.