Acoustic Specifications for separating walls and floors regarding Flats and conversions

Under Approved Document E, all residential properties must provide a good level of acoustic insulation between dwellings. The table summarises the required decibel standards of performance for compliance.


Element of Construction
internal walls that include a door are exempt from this requirement.
Airborne sound
insulation (site test result) minimum value DnT,w+Ctr dB
Impact sound
insulation (site test result) maximum value L'nT,w dB
Airborne sound
insulation (lab test result) minimum value Rw dB
Separating walls between dwellings. 45 Min    
Separating walls between rooms used for residential purposes. 43 Min    
Separating walls between rooms created by a change of use. 43 Min    
Separating floors between dwellings and rooms used for residential purposes. 43 Min 62 Max  
Separating floors between rooms created by a change of use. 43 Min 64 Max  
An internal wall or floor between a bathroom/W.C. and a habitable room. Also between bedrooms and between bedrooms and any other room in the dwelling.     40 Min


Methods of Compliance

There are currently two methods available to show compliance to Approved Document E.

These are Robust Details and Pre-Completion Testing. Both methods have complex considerations.


Robust Details
The appropriate detail is selected from the Robust Details handbook. Contact us for more information.

Pre-Completion Testing
An appropriate system is installed which must then be tested by an accredited testing service to show compliance.

Our expertise is available to assist developers, architects and designers with specifications and bespoke acoustic solutions.