Existing waterproofing with no added thermal insulation
Single layer waterproofing
Reinforced bitumen membranes should only be applied over a continuous substrate which provides full support. Substrate Materials used to form the roof deck in flat roofs should be those listed in BS 6229:2003 Flat roofs with continuously supported coverings – Code of practice and conform to the relevant requirements in BS 8217:2005 Reinforced bitumen membranes – Code of practice.
The waterproofing system should conform to the requirements of British Standard 8747:2007 Reinforced Bitumen membranes (RBMs) for roofing – Guide to selection and specification and be installed in accordance with British Standard BS 8217:2005.