Technical & Regulatory FAQs: Scottish Building Standards

 Under the Scottish Building Standards, new-build domestic properties generally require pre-completion testing in two major compliance areas before a local authority verifier will grant a completion certificate:

• Air Tightness Testing (Section 6 - Energy): Mandatory for all new-build homes to ensure the building fabric meets or exceeds the target air permeability rate set out in the Design SAP calculation.
• Sound Insulation Testing (Section 5 - Noise): Mandatory for new-build attached dwellings (flats and terraced/semi-detached houses) to prove that separating walls and floors meet the required airborne and impact sound reduction performance.

 To comply with the Scottish Building Standards Technical Handbook (Section 5), separating structures must achieve the following minimum sound reduction indices:

• New-Build Separating Walls: Minimum airborne sound insulation of 56 dB (DnT,w).
• New-Build Separating Floors: Minimum airborne sound insulation of 56 dB (DnT,w) AND a maximum impact sound transmission level of 56 dB (L'nT,w).
• Note: For conversions of existing buildings, the requirement is slightly lower at 53 dB for airborne noise and a maximum of 58 dB for impact noise.

 Sound insulation testing is required for any new or converted building under Section 5 where there is a separating wall or floor between different sub-structures (e.g., separating two flats, or a semi-detached house).

• Exemption Note: You may be exempt from mandatory pre-completion sound testing if the separating walls or floors have been built strictly in accordance with approved Robust Details (Scotland) design criteria, and the plot has been formally registered with Robust Details Ltd prior to construction beginning.

 If the property fails to meet the target set in the SAP calculation, the building warrant cannot be signed off. As an approved ATTMA tester, Planit X doesn't just pack up and leave. We carry out on-site diagnostics using smoke pencils and thermal indicators to locate the primary air leakage paths (typically around structural penetrations, pocket doors, skirtings, or window seals). Once the site team seals these defects, we can perform an immediate re-test to keep your project moving. 

 Local Authority Verifiers in Scotland are legally bound to ensure testing is completed by competent, accredited individuals. Planit X is fully certified under ATTMA (for air testing) and SITMA (for sound testing). Because our testing equipment is UKAS-calibrated and our engineers are registered, your compliance certificates are uploaded straight to national databases, meaning your local verifier can immediately accept them without questioning the data, preventing costly sign-off delays. 

 While historical standards allowed higher leakage, current Section 6 (Energy) standards heavily penalize poor airtightness. The absolute maximum limit allowed by the standards is 7.0 m³/h.m² at 50 Pa. However, to pass the overall carbon emissions targets within your SAP calculation, your architectural designer will usually set a much stricter target—typically between 3.0 m³/h.m² and 5.0 m³/h.m². Your final ATTMA blower-door test must achieve or beat this design target.