What is tested
Tests are carried out between pairs of rooms that share a separating wall or floor.
- Airborne sound, such as voices and television, is reported as DnT,w + Ctr. It's a minimum standard: higher is better.
- Impact sound, such as footsteps, is tested on separating floors and reported as L'nT,w. It's a maximum: lower is better.
The standards
| Homes | Walls: airborne | Floors and stairs: airborne | Floors and stairs: impact |
|---|---|---|---|
| Purpose-built houses and flats | 45 dB minimum | 45 dB minimum | 62 dB maximum |
| Formed by material change of use | 43 dB minimum | 43 dB minimum | 64 dB maximum |
Rooms for residential purposes, such as student rooms, have their own values in Table 0.1b.
Groups and sub-groups
Results only apply to the construction tested, so a development is split into groups: houses, flats, and rooms for residential purposes. Within each group, sub-groups are formed where constructions differ significantly: by type of separating wall for houses, and by type of separating floor and wall for flats. Different flanking details can need further sub-groups.
How many tests
- Building control asks for one set of tests between the first homes scheduled for completion in each group or sub-group, whatever its size. A site with a single pair of homes should still be tested.
- As more homes are ready, building control should ask for at least one set of tests for every ten homes in a group or sub-group, assuming none fail.
- Testing should be more frequent at the start of a run of completions, to catch problems early.
| Type of home | A set of tests is normally |
|---|---|
| Houses (including bungalows) | 2 airborne tests across the separating wall |
| Flats with a separating floor but no separating wall | 4 tests: 2 airborne and 2 impact across the floor |
| Flats with a separating floor and wall | 6 tests: 4 airborne (2 across the wall, 2 across the floor) and 2 impact |
When to test
Once the homes on both sides are essentially complete apart from decoration. Impact tests are carried out without soft floor coverings such as carpet or foam-backed vinyl. Tests aren't carried out between a home and a corridor, stairwell or hallway.
If a set fails
- A set fails if any one of its tests doesn't meet the standard.
- Remedial treatment should be applied to the rooms that failed, appropriate to the cause.
- The developer should show building control that other rooms and homes sharing the construction meet the standard: by more testing, by applying the remedy to them too, or by showing the cause doesn't affect them.
- The rate of testing should go up until building control is satisfied the problem is solved, and the effect of the remedy is normally checked by further testing.
Robust Details instead of testing
For new houses and buildings containing flats, separating walls and floors built to a design detail approved by Robust Details Ltd don't need pre-completion testing, as long as building control is notified of the detail and its unique number, and the work follows the detail. A builder can use Robust Details for some separating structures and test the rest.
Who tests, and reporting
Approved Document E says testing should be done by a test body with appropriate third-party accreditation, preferably UKAS accreditation for field measurements, and that members of the ANC Registration Scheme are regarded as suitably qualified. The results must be given to building control under Regulation 41.
This guide summarises Approved Document E; it isn't compliance advice. Your building control body sets the testing programme for a development, so agree it with them early.
How TestConnect helps
Post sets of tests per group or sub-group to sound testers who cover the area, check both sides are ready before the visit, and keep every result, fail and retest against the plots tested. See sound testing.
Sources
- Approved Document E, 2003 edition incorporating 2004, 2010, 2013 and 2015 amendments (GOV.UK): Tables 0.1a and 0.1b, paragraphs 0.4, 1.8 to 1.39
- The Building Regulations 2010, Regulation 41 (legislation.gov.uk)
- Designing Buildings Wiki: pre-completion sound testing
Last checked: October 2026.