ISOVER RD Party Wall Roll RD Party Wall Roll is a glass mineral wool roll that can be used to reduce the passage of sound across a masonry cavity separating (party) wall and minimise air movement within the cavity, improving its thermal performance. When used as part of Robust Detail separating wall constructions E-WM-17, E-WM-20 & E-WM-24, it removes the need for costly pre-completion sound testing and can achieve +5dB over acoustic performance requirements set out in Building Regulations Approved Document E (England & Wales). Rolls are ready-cut to 2 x 455mm to fit between standard wall tie spacing.