Q. Once Cromaprufe has been applied to concrete can the polystyrene boards be placed directly on top as part of underfloor heating system – or will visqueen need to be applied in between & will the Cromaprufe attack the polystyrene?
A. Not ideally the best way to achieve a DPC for underfloor heating – usually foil is used – however the Cromaprufe will not attack the Polystyrene as this is emulsion based. Yes this can be applied directly on top, it will remain slightly tacky due to nature/rubberised qualities of material, however as soon as the underfloor heating is activated this will dry.