Sound Testing for Homes: What to Agree Before the Test Date

When should pre-completion sound testing be planned?

For relevant new dwelling-houses, flats and rooms for residential purposes, Approved Document E provides guidance on sound insulation testing, including how properties are grouped and sampled. Building Control bodies determine the properties selected for testing, so the test programme should be agreed with the project team rather than assumed from another development.

Planning early also gives the project team time to identify changes in construction, confirm access and make sure the relevant spaces will be ready.

Confirm which constructions need testing

Start with the latest drawings and identify the separating walls and floors between relevant dwellings or rooms.

Consider:

• different wall or floor constructions;
• different dwelling types or layouts;
• changes made during construction;
• phased handovers; and
• how properties have been grouped for testing.

Approved Document E sets out a normal testing programme based on groups or sub-groups of properties. It also states that Building Control should consult developers about completion times and select properties for testing. Where no tests have failed, the guidance describes at least one set of tests for every ten dwelling-houses, flats or rooms for residential purposes within a group or sub-group.

This means a test result should not simply be carried across to a materially different construction without considering whether it is representative.

Prepare the building before the test date

Testing should take place when the relevant spaces are sufficiently complete and accessible.

Before the visit, check that:

• ✓the relevant walls and floors are complete;
• ✓rooms on both sides of the separating construction can be accessed;
• ✓doors and other relevant elements are installed as required;
• ✓construction changes have been recorded; and
• ✓disruptive work can be kept away from the test areas.

Approved Document E states that testing should be carried out once the relevant spaces either side of a separating element are complete, and its guidance emphasises following appropriate construction details to reduce the likelihood of a failed test.

It is also worth checking the installed construction against the latest drawings. Differences in floor build-ups, wall details, junctions or service penetrations can be important when investigating a result later.

Know what the test will measure

Depending on the building and separating construction, testing can include both airborne and impact sound.

Airborne sound testing assesses sound insulation through separating walls or floors. Impact testing assesses sound transmitted through a separating floor, using controlled impact on the floor above.

The exact combination depends on the building arrangement. Approved Document E sets out different test sets for dwelling-houses and flats, including combinations of airborne and impact tests for flats with separating floors and walls.

What should be checked before testing?

Have the information needed to identify the construction and test locations available before the engineer arrives.

Useful information can include:

• the latest drawings;
• separating wall and floor build-ups;
• the dwelling or room references;
• details of relevant construction changes; and
• the planned completion and handover sequence.

This helps the testing programme reflect what has actually been built rather than relying on assumptions made earlier in the project.

What should you expect from the sound test report?

A sound test report should make it clear what was tested, where the tests were carried out and what results were obtained.

Approved Document E specifies information to be recorded for pre-completion testing, including the building address, property type, test dates, testing organisation, rooms tested, measured sound insulation values and the applicable performance values. It also requires details of the test procedures and equipment.

For project teams, keeping the report clearly linked to the relevant dwelling and construction makes the evidence easier to review and submit as part of the completion process.

What happens if a sound test fails?

A failed result should be investigated rather than treated as an isolated number.

The cause may relate to the separating construction, junctions, flanking elements, workmanship or other details. Approved Document E states that appropriate remedial treatment should follow a failed set of tests and that additional testing may be needed to demonstrate that the required performance has been achieved.

Where a problem affects a repeated construction, the implications may extend beyond the rooms originally tested. This is why identifying the cause and recording the remedial work is important.

Keep the testing evidence with the project record

Keep the completed test reports alongside the drawings and construction information they relate to. For phased developments, record which results represent each group or construction type and update the testing plan if the construction changes.