There is a lot written about the insulating values of loft insulation, but what about all those flat roofs? Flat roof insulation needs to be considered and they will be covered in the Governments upcoming Green Deal initiative.
There are two basic ways that flat roofs have been insulated: from the outside of the property and from the inside of the property. If you are insulating from the inside of the property you need to be wary of condensation issues that might arise from lack of ventilation occurring between your insulation and the ‘cold roof’ on top. Building regulations state that you should have a 50mm gap between the insulation and the roof to help avoid this.
By contrast if you insulate the outside of the roof you won’t have to worry about condensation problems and so most modern methods use this ‘warm roof’ solution so the insulation is added to the outside of the roof.