Guest Blog Superglass – Party Wall Roll

Party Wall Function

While the division between adjoining properties might have been assumed to be an area of neutral heat loss, in that no transfer would take place between spaces at similar temperatures, research confirms that cavity party walls are subject to significant energy leakage.

Referred to as Thermal Bypass, the phenomenon is now taken into consideration within the current Building Regulations and potentially represents a major concern to house builders and designers in terms of achieving compliance for semi-detached and terraced properties.

This is because on typical floor plans, where the footprint is quite narrow, the party wall presents a larger area than the front or back, to which the Building Regulations now assign a U-Value of 0.5 W/m2K unless specific action is taken to improve its performance. However, once heat has escaped into the cavity it is carried upwards to the roof space; primarily due to wind drift at the junctions with the outside walls creating a stack effect. No developer will want to accept the onerous U-Value penalty, but filling the cavity could also compromise the acoustic insulation afforded by the original arrangement.

Fortunately Superglass Party Wall Insulation is not only a very good thermal insulant, but also offers excellent acoustic benefits.

Superglass Party Wall Roll

Superglass Party Wall Roll is designed to provide thermal and acoustic insulation and help provide a zero U-Value within masonry party or separating walls as described within Approved Document L1A (England & Wales) and Technical Handbook Section 6 (Scotland). Party Wall Roll may be used as a component in a number of Robust Details Solutions including proprietary systems E-WM-22, E-WM-23 & E-WM-27 (England & Wales) and V-WM-27 (Scotland). It may also be used in party wall systems which require on-site pre-completion (England & Wales) or post-completion (Scotland) acoustic testing.


When installed in the cavity of a masonry party or separating wall in conjunction with effective edge sealing, it will negate the effect of Thermal Bypass associated with such walls, whilst not diminishing their acoustic performance.

Robust Details

Robust Details Limited was formed in December 2003 in response to the house building industry’s request for an alternative to pre-completion sound testing, as a means of satisfying the sound insulation requirements of the Building Regulations.

As Superglass insulation products have been specifically referenced in the approved Robust Details Handbook, they can be installed with the confidence that the chosen build method will satisfy current Building Regulations.


Please click here to find your local CCF branch and contact them for more information or request a quote.


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