
Wall Ties & Restraint Fixings
Approved Document E
Approved Document E: Resistance to the Passage of Sound
This document specifies the acoustic performance requirements of ties suitable for use in separating walls (Type A ) and external walls (Type B) of new build dwellings.
Type A ties must have a measured dynamic stiffness of <4.8MN/m3 for the specified minimum cavity, at a standard density.
Type A ties throughout the site are indicated by this logo e.g. Ancon Staifix HRT4, ACOU Acoustic Wall Tie Range.

Ancon Staifix HRT4
All Ancon ties which cross a cavity meet the requirements of Type B.
How the dynamic stiffness of wall ties is measured
The ends of six samples of each tie are cast into 100mm square concrete blocks, the blocks are suspended, one block excited and the frequency response measured. From these tests the mean dynamic stiffness is calculated for the specific cavity and multiplied by the tie density (usually 2.5 tie/m2). The results are shown in MN/m3.
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CE, UKCA and CE UKNI marking from Leviat
From January 1st 2021, the UK will recognise both the EU CE marking approvals, for a time limited period, and the new UK based approval system, which will be known as the UKCA mark. The EU will only recognise CE marking by EU notified bodies as proof of efficacy moving forwards. Leviat has been working closely with both EU notified and UK approved bodies to ensure compliance is achieved at the earliest possible opportunity and we can confirm that we have obtained all relevant certification.