Architectural Masonry

Public Sector


New RD enhancement for E-WM-5 and E-WM-11Party Walls in Approved Document L1a 2010


Enhancements for Besblock Star Performer Robust Detail E-WM-5 and Star Performer in E-WM-11: are both now accredited for use with full fill cavity insulation within the separating / party wall cavity. (E-WM-11 achieves 3 CSH credits).

New Approved Document L1A 2010 now determines the following heat loss through separating walls:

Party wall construction U-value (W/m2K)
Solid 0.0
Unfilled cavity with no effective edge sealing 0.5
Unfilled cavity with effective sealing around all exposed edges
And inline with insulation layers in abutting elements
A fully filled cavity with effective edge sealing at all exposed
edges and inline with insulation layers in abutting elements

As a result, the Carbon Emission calculation in SAP 2009 for the Notional Dwelling includes a party wall heat loss of zero.

If a cavity party wall is used and the cavity therein remains un- insulated, higher standards elsewhere in the buildings fabric and/or its services will be required to compensate for this reduction of the TER ( Target Emission Rate).

Download the new E-WM-5 Details (PDF)

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