Building Regulations
Renotherm is used to create non-ventilated hybrid warm deck structures for roofs, walls and floors that comply to Building Regulations. Unventilated lofts are much more efficient to insulate against heat loss and sound transmission and provide useful, clean storage areas. Renotherm’s insulation performance is amongst the best available and, because the foam seals all gaps and moulds itself to all contours, it minimises unwanted air leakage. Renotherm creates its own vapour control layer so there can be no risk of surface or interstitial condensation.
Thermal Performance
Building Regulations
The 2006 Dwelling Emission Rate (DER) is currently set at 20% improvement over the 2002 Regulations. There is considerable complexity and flexibility in design criteria to meet carbon dioxide emission rates but the table below shows the best ‘U’ Value starting point to avoid too many iterations in showing compliance to SAP 2005.
The Scottish Building Regulations have fixed ‘U’ Value requirements according to whether or not the heating boiler is ‘A’ rated.
Air Permeability and Cold Bridging
It is also a requirement to demonstrate that the quality of construction has been achieved by adopting accredited details such as the Renotherm BBA 02/3964 certificate and undertaking an air pressure test to confirm the specified design air permeability has been achieved. A limit of 10m3/m2/h at 50 Pa for air permeability is allowed. Renotherm will assist dramatically in reducing air leakage and cold bridging.
Support for the Designer
Renotherm’s technical department provides free ‘U’ value and condensation risk calculations and gives recommended foam depths to achieve the required Dwelling Emission Rate. ‘U’ value calculations are carried out using the methods in ISO 6946 (walls and roofs) and ISO 13370 (ground floors). Condensation risk analyses are calculated using the method in BSEN ISO 13788:2002 (and BS 5250 Appendix D): Code of Practice for the Control of Condensation in Buildings. Calculations can be provided for roofs, walls and floors and may be submitted to Building Control Departments to demonstrate compliance with Building Regulations.
