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An Overview of Approved Document E

Part E Building Regulations Explained

Weighing in at 86 pages, Approved Document E (Resistance to the Passage of Sound) is no easy read. But if you’re involved in the building of a new property or the renovation of an existing property (particularly where you’re looking at a change of use from a single dwelling to a number of apartments), you’re going to need to be familiar with these complex regulations.

Whilst we strongly recommend you read the whole document (you can download it here), it may be easier if you familiarise yourself with our digest version first.

Approved Document E is divided into four main sections:

  • E1 Protection against sound from other parts of the building and adjoining buildings
  • E2 Protection against sound within a dwelling house etc
  • E3 Reverberation in the common internal parts of buildings containing flats or rooms for residential purposes
  • E4 Acoustic conditions in schools

It is E1, E2 and E3 we’ll be looking at. E4 is a little outside the scope of this website!

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‘Dwelling House’ or ‘Rooms for Residential Purposes’?

A dwelling house is, according the government’s planning portal:

“A self-contained building or part of a building used as a residential accommodation, and usually housing a single household. A dwelling may be a house, bungalow, flat, maisonette or converted farm building.”

A room for residential purposes is:

“[A] room, or a suite of rooms, which is not a dwelling house or flat and which is used by one or more persons to live and sleep and includes a room in a hostel, an hotel, a boarding house, a hall of residence or a residential home, but does not include a room in a hospital, or other similar establishment, used for patient accommodation.”

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For purpose built dwelling houses, Part E demands 45dB (decibels) of airborne sound insulation for walls, floors and stairs; and 62dB of impact sound insulation for floors and stairs.

If the dwelling is not purpose built but has undergone ‘a material change of use’ (i.e. it used to be a warehouse, school, church, prison, factory, office etc), Part E demands 43dB (decibels) of airborne sound insulation for walls, floors and stairs; and 63dB of impact sound insulation for floors and stairs.

For rooms for a residential purpose, the same performance is required, with the exception of walls, which must have an airborne sound insulation performance of 43dB.

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There are two means of establishing whether or not a dwelling house or room for residential purposes is compliant with Part E.

The main method is ‘pre-completion testing’. The testing times are negotiated between building control bodies and the developers, and testing is carried out once the dwellings either side of a separating element are essentially complete. The testing must be carried out by a third party with appropriate accreditation (e.g. UKAS).

The other approved method of achieving compliance is ‘robust detail’. This involves following a pre-approved build-up in order to achieve the necessary sound insulation levels. Robust detail audit sites in order to ensure compliance. You can find out more about robust detail here.

In the event of a failure, remedial action must be taken and new tests must be arranged.

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The next 50 pages or so of Approved Document E, give examples of wall and floor constructions to ensure compliance with the regulations. The examples include:

  • Separating walls and associated flanking constructions for new buildings
  • Separating floor and associated flanking constructions for new buildings
  • Dwelling houses and flats formed by material change of use
  • Internal wall and floors for new buildings
  • Rooms for residential purposes

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‘Reverberation’ is, essentially, another word for ‘echo’, the reflection of sound from a hard surface. The simplest way to describe the difference is that with an echo, there is no overlap with the original sound, whereas with reverberation there is. As such, reverberation is a more disorienting effect than an echo. In the common areas of residential properties, such as corridors and stairwells, the ‘reverberation time should be less than 1.5 seconds. This is considerably less arduous than the requirement for schools, which ranges from 0.6 to 0.8 of a second.

The reverberation time of a room or space is defined as the time it takes for sound to decay by 60dB. For example, if the sound in a room took 10 seconds to decay from 100dB to 40dB, the reverberation time would be 10 seconds. This can also be written as the T60 time.

You can find out more about reverberation in our recent blog post: Sound Absorption and the Rise of Reverberation.

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  • Part E applies to all dwellings (including temporary) with the exception of hospital rooms or similar
  • Part E looks at sound insulation performance for airborne and impact sound
  • Testing can be done pre-completion or a robust detail approach can be taken
  • Testing must be carried out by a UKAS-approved (or similar) third party
  • Corridors and stairwells etc must demonstrate a reverberation time of 1.5 seconds or less

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