A. Yes – but ONLY if Self Levelling is mixed with SBR at 1 x 5lt to 1 x bag of S/levelling. Then the underfloor heating can be applied. However the best method to save on time and labour is to make a slurry with 1kg of cement and 1ltr SBR - this will act as the DPC and provide a suitable finish for the underfloor heating.