Wave Dynamics GuidesWhat Is Sound Insulation Testing?
What sound insulation testing is, when it is needed under TGD E and Approved Document E, how airborne and impact tests work and how to prepare.
In Short
Sound insulation testing measures how well a completed separating wall or floor stops sound passing between homes. It is carried out on site before occupation to show that the building meets the sound requirements of the Building Regulations, such as TGD E in Ireland and Approved Document E in England and Wales.
- Two tests: airborne sound (voices, TV) through walls and floors, and impact sound (footsteps) through floors.
- Results in Ireland are reported as DnT,w (airborne, higher is better) and L′nT,w (impact, lower is better).
- Testing is done near completion, once doors, windows and floor finishes are in place.
- Tests should be carried out by a registered tester, such as a SITRI or SITMA member.
What Sound Insulation Testing Measures
A sound insulation test checks the real, as-built performance of a separating element between two dwellings or between a dwelling and another space. Laboratory ratings for a wall or floor product are useful at design stage, but what Building Control cares about is how the finished construction performs once junctions, services, fixings and workmanship are included.
There are two types of test. An airborne test uses a loudspeaker to generate a high, steady noise level in one room and measures how much is heard in the room on the other side. An impact test uses a standard tapping machine on the floor above and measures the noise in the room below. The results are standardised and rated as single numbers: DnT,w for airborne sound and L′nT,w for impact sound.
When Is Testing Needed?
In Ireland, TGD E (2014) asks for pre-completion testing of new dwellings, including apartments, duplexes and houses with a separating wall, and of dwellings formed by a material change of use. In England and Wales, Approved Document E requires testing unless a registered Robust Detail is used. Northern Ireland and Scotland have their own guidance with similar testing routes.
Many projects also test beyond the minimum, for example a first test set on early units to prove the details before the rest of the block is finished. That approach finds problems while they are still cheap to fix.
How a Test Day Works
- The tester agrees the test pairs with the contractor, covering each separating construction type.
- Rooms need to be empty, quiet and finished, with doors and windows fitted and closed.
- Airborne measurements are taken with a source in several positions, plus background noise and reverberation time in the receiving room.
- Impact measurements are taken with the tapping machine in several positions on the floor above.
- Results are calculated to I.S. EN ISO 16283 and rated to I.S. EN ISO 717, then compared with the regulation criteria.
A typical apartment test set can often be completed in a day, depending on access and the number of pairs.
How to Prepare for a Pass
Most failures come from small construction details rather than the main wall or floor build-up. Before testing, check that sockets and services are not back to back, that gaps at wall heads and floor perimeters are sealed, that resilient layers under screeds are continuous and that skirting boards are not bridging floating floors. Our guide to why sound insulation tests fail covers the common causes.
Frequently Asked Questions
Who can carry out sound insulation testing in Ireland?
Testing should be carried out by a competent tester registered with a recognised scheme. In Ireland that is the Sound Insulation Testing Register (Ireland), known as SITRI. In the UK, SITMA and UKAS-accredited testing are the recognised routes.
What happens if a test fails?
The cause is investigated, remedial work is designed and carried out, and the pair is retested. Other similar constructions in the building are usually reviewed too, so the same problem is not repeated.
Do houses need sound testing?
Detached houses do not have separating walls, so they are not tested. Semi-detached and terraced houses with a party wall, and all apartments, fall within the scope of TGD E.
This guide gives general information and is not a substitute for project-specific advice. Requirements change, so always check the current regulations, guidance and your planning conditions. Ask our team about your project.
Jon Maguire (BSc Hons MIOA) brings over 8 years of expertise in acoustic consultancy, specialising in environmental acoustics with a focus on 3D modelling, assessments, and detailed design for industrial, commercial, and energy projects. He has lead noise assessments for key clients while thriving in multidisciplinary environments. Jon’s diplomatic communication skills are ideal for stakeholder consultation.
Jack is a Field Engineer at Wave Dynamics, supporting the delivery of environmental monitoring and acoustic consultancy services through detailed on-site fieldwork. He has hands-on experience in noise monitoring, vibration monitoring, and dust monitoring across a variety of infrastructure, construction, and environmental projects. Jack is involved in the setup, operation, and maintenance of monitoring equipment, ensuring accurate data collection in line with relevant standards and project requirements. He works closely with consultants and project teams, providing reliable field support that underpins high-quality assessments and reporting.
Aidan is the Director for all U.K Operations and has worked in multiple industries including for clients in the UK and internationally operating in the residential, industry, healthcare, education, and construction sectors.
