Building Regulations do not have the power to say you cannot use a particular material. If you can demonstrate that the materials you use meet the requirements of the regulations then you can use them. I am constantly asked does anhydrite screed meet Building Regulations........it is a silly question really. If it was used as a structural ring beam to support a roof it would not work and the building would then not meet the regulations (Part A). However if it is used as it is designed to be used i.e. a levelling screed it is perfectly acceptable. It is not about what the materials are but how they are used.
