Wave Dynamics GuidesApproved Document E vs TGD E: Sound Rules Across Ireland and the UK
How sound insulation requirements differ between Ireland (TGD E), England and Wales (Approved Document E), Northern Ireland and Scotland.
In Short
Ireland, England and Wales, Northern Ireland and Scotland each have their own guidance on sound insulation between homes. They all measure on site, but they use different ratings and limits: Ireland uses DnT,w, while England and Wales use DnT,w + Ctr, which penalises low-frequency sound such as bass music and traffic.
- Ireland: TGD E (2014), airborne and impact criteria between dwellings.
- England and Wales: Approved Document E, with Robust Details as an alternative to testing.
- Northern Ireland: Technical Booklet G. Scotland: Section 5 of the Technical Handbooks.
- The same wall can pass in one jurisdiction and fail in another, so design to the right standard.
Why the Differences Matter
Designers and contractors working on both sides of the border, or across the Irish Sea, often reuse wall and floor details. That is risky. The ratings are calculated differently and the limits are not the same, so a construction that comfortably passes TGD E may struggle against Approved Document E, and the reverse can happen for impact sound.
Ireland: TGD E
TGD E (2014) asks for a mean DnT,w of at least 53 dB for separating walls and floors and a mean L′nT,w of no more than 58 dB for separating floors, confirmed by pre-completion testing. Read more in our TGD E guide.
England and Wales: Approved Document E
Approved Document E sets airborne performance as DnT,w + Ctr. The Ctr term is a spectrum adaptation that gives more weight to low frequencies, so lightweight constructions with weak bass performance are marked down. For new-build dwellings the guidance asks for at least 45 dB DnT,w + Ctr for walls and floors and no more than 62 dB L′nT,w for floors, with relaxed values for material change of use. Housebuilders can avoid testing by registering Robust Details, which are pre-approved constructions built to a strict specification.
Northern Ireland and Scotland
Northern Ireland follows Technical Booklet G, which uses a testing regime and criteria closely aligned with Approved Document E. Scotland follows Section 5 of the Building Standards Technical Handbooks, which uses its own ratings and generally more demanding values. If you are building in more than one jurisdiction, confirm the applicable criteria for each block at design stage.
Practical Advice for Cross-Border Projects
- Choose wall and floor types against the strictest criteria that apply to the project.
- Check that junction details suit the local guidance, not just the separating element.
- Use a tester registered for that jurisdiction: SITRI in Ireland, SITMA or UKAS-accredited testing in the UK.
- Plan an early first test set to prove the details before the rest of the building is finished.
Frequently Asked Questions
What is Ctr?
Ctr is a correction defined in ISO 717-1 that adjusts the airborne rating for low-frequency noise, such as road traffic and amplified music. It is usually a negative number, so it lowers the result.
Can Robust Details be used in Ireland?
Robust Details is a scheme for England, Wales and Northern Ireland. In Ireland, compliance with TGD E is confirmed through pre-completion testing.
Does Wave Dynamics test in Northern Ireland and Great Britain?
Yes. We carry out SITRI and SITMA certified testing across Ireland, Northern Ireland and Great Britain from our Dublin, Wexford, Cork, Belfast and London offices.
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.
