<b></b><p></p><p><b><b>Tim Palmer examines what effect imminent changes to new sound and thermal regulations will have on the insulation sector</b></b><br><b>Cavity wall insulation for existing buildings is at the heart of the government&amp;’s ongoing energy efficiency strategy and a major contributor in reducing emissions of carbon dioxide, the main greenhouse gas. </b><br>In the new-build field the process will play a major role in meeting new Building Regulations - due in 2002 - when a 0.35 U-value for walls becomes the standard requirement. According to National Cavity Insulation Association (NCIA) director Gillian Allder this represents the optimum energy efficiency requirement in relation to construction costs and a valuable opportunity to conserve fuel and combat pollution and global warming. </p><p>She says: &amp;“Meanwhile, the current basic requirement of 0.45 for walls is essential in the context of energy conservation, coupled with the need to calculate this taking into account cold bridging by internal and external mortar joints. </p><p>&amp;“Wall construction with a 65mm cavity with cavity fill is a cheaper way of arriving at the existing requirement than any other method as there&amp;’s little increase in overall wall thickness and standard 100mm mid-density blocks on the inner leaf remain suitable (provided density is no greater than …