[PRODUCTS] Thermal bypasses and cavity party walls
Amendments to Section 6 of Scotland’s Building Standards, which will come into force in October, recognise the thermal bypass effect in party wall cavities that separate domestic and non-domestic buildings. They will require new-build party walls to be fully filled with an insulation material that has been shown to limit air movement, in order to achieve a U-value of zero.
Research funded by Eurisol, the UK Mineral Wool Association, proves that the thermal performance of party walls can be significantly improved by insulating with mineral wool, without compromising acoustic performance. This set out to quantify the effect of thermal bypass on energy and CO2 performance in dwellings and demonstrate how insulating party cavity walls can reduce or eliminate this effect.
A pair of attached masonry dwellings with a masonry cavity party wall were tested. Additional testing conducted after the cavity in the party wall was insulated with blown mineral wool showed that the insulation eliminated party wall thermal bypass. It also showed that, if this type of party cavity wall is completely filled with mineral wool, its
effective U-value could potentially be reduced to zero, when combined with the existing mineral wool-filled socks at the cavity’s edges.