U-values

For new dwellings, U-values for external walls can exceed Part L requirements without difficulty, but are typically in the range of 0.18-0.25 W/m²K, which is achieved using standard masonry construction methods. The development of high performance insulation products and low conductivity wall ties that have helped ensure cavity widths remain relatively modest at around 100 - 150mm.

U-values for ground floors can also easily exceed regulatory requirements, with beam and block flooring systems capable of delivering U-values as low as 0.08 W/m²K; significantly better than 0.13 W/m²K detailed in Part L1A for new dwellings.