Here we look at what Part E is, and how to comply with the regulations.
What is Part E?
Part E of the building regulations offers guidance on providing reasonable standards of sound insulation in residential buildings within England and Wales. It applies to all dwelling-houses, flats and rooms for residential purposes, from homes to hotels, and covers both new buildings and those undergoing refurbishment or conversion from a different use.
Part E aims to improve occupant comfort and wellbeing by reducing noise transmission between neighbouring homes, as well as between internal spaces.
What construction elements does Part E cover?
To comply with Part E of the building regulations, residential buildings must use sound insulation systems that meet the required airborne and impact noise insulation levels.
Internal walls and floors
For internal walls, the required airborne sound insulation level is Rw 40 dB (this refers to laboratory test results). It applies to internal walls between bedrooms and other rooms, as well as between bathrooms and other rooms. However, it doesn’t include internal walls containing a door.
Internal floors must also achieve minimum airborne sound insulation levels of Rw 40 dB.
In Scotland, the equivalent guidance is given in Section 5: Noise of the Domestic Technical Handbook. This limits sound transmission between internal walls and floors forming rooms that are within dwellings or residential buildings, and which can be used for sleeping. Minimum airborne sound insulation levels are Rw 43 dB for internal floors and Rw 40 dB for internal walls.
Separating walls and floors
Separating floors between new homes and purpose-built rooms for residential purposes must meet a minimum airborne sound insulation level of 45 dB DnT,w + Ctr (or 56 dB DnT,w in Scotland). This refers to on-site test results. For rooms created by a change of use or conversion, the minimum is 43 dB DnT,w + Ctr (or 53 dB DnT,w in Scotland).
The maximum impact sound transmission level is LnTw 62 dB (LnTw 56 dB In Scotland) for separating floors between new homes and purpose-built rooms for residential purposes. Between rooms created by a change of use or conversion, it’s LnTw 64 dB (LnTw 58 dB In Scotland).
Separating walls between new homes must meet a minimum airborne sound insulation level of 45 dB DnT,w + Ctr. For purpose-built rooms for residential purposes, and rooms created by a change of use or conversion, this is 43 dB DnT,w + Ctr.
In Scotland, separating walls between new homes, purpose-built rooms for residential purposes and conversions must meet a minimum airborne sound insulation level of 56 dB DnT,w. For homes or rooms created by a change of use or conversion, this is 53 dB DnT,w.
How to comply with Part E
Testing doesn’t need to be carried out for internal constructions, as the local Building Control service will make sure they meet performance requirements at the planning stage.
For separating constructions, however, Part E requires that the first of each building type on new housing developments undergo pre-completion testing to demonstrate the required levels of sound insulation. After this, 1 in 10 of each property type should be tested. Pre-completion testing takes place before soft coverings like flooring are installed.
If buildings fail this testing, remedial work should be done to address issues, and other properties will need to be tested as well. This process is time-consuming and costly, which means it’s worth getting it right first time around.
In addition to testing, housebuilders need to show they have followed either guidance constructions or manufacturers’ proprietary systems, as these help ensure that systems meet the requirements of Part E.
Robust Details provides an alternative route to pre-completion testing for new-build houses and apartments. To use it, you need to register plots through the website, making it clear which specifications you will use. You will pay a fee to receive a registration certificate to pass on to your building control authority before you start work.
British Gypsum Approved Systems have been laboratory tested, and achieve or exceed the required performance levels for internal wall construction when used correctly. Take a look at our sound insulation products and systems to find out more.