Flanking transmission control for stair treatment

In all cases it may be necessary to control flanking transmission in order to achieve the performance standards set out in Table 1a of the section entitled "Guidance - Performance and introduction to provisions" (see Section 4: Junction requirements for material change of use). Special attention needs to be given to situations where flanking walls or floors are continuous across separating walls or floors as a result of the conversion work. In such instances additional treatments may be required to control flanking transmission along these continuous elements. Specialist advice may be needed.