What type of insulation should I use/specify in conjunction with the waterproofing in the cellar?
The application of Oldroyd membranes (http://www.safeguardeurope.com/cad/XV-001.pdf) as part of the process to provide a dry decorative surface is very broad and very often there is the temptation to install internal thermal insulation directly behind the wall finish, in front of the membrane, as part of the dry wall system. Irrespective of the construction or system being employed this practice has the potential to cause condensation behind the insulation and if a membrane has been used it is likely to form on the surface of the membrane. If insulation is to be installed in conjunction with an Oldroyd membrane system it should be directly behind the wall finish and it should be 'closed-cell', for example Knauf, Cellotex or Kingspan.