Building Regulations Wales — Approved Documents Guide

Building Regulations in Wales

Since devolution, building regulations in Wales are the responsibility of the Welsh Government. Wales uses the same Approved Document framework as England (Parts A through S), but has the power to set different standards. The Building Regulations etc. (Amendment) (Wales) Regulations have introduced Welsh-specific requirements in several areas, most notably energy performance.

For most day-to-day building work, the process in Wales is very similar to England. The key differences are in the technical standards (particularly energy) rather than the administrative process.

Where Wales Differs from England

Part L — Conservation of Fuel and Power

This is the most significant area of divergence. Wales published its own edition of Approved Document L in 2022, with distinct requirements including:

• Welsh-specific target CO₂ emission rates (TER) for new dwellings
• Different fabric energy efficiency standard (FEES) thresholds
• Welsh U-value backstop values that may differ from England on some elements
• SAP calculations use the same methodology but with Welsh-specific target values
• Transitional arrangements may differ from England — check which edition applies to your project

Part O — Overheating

Wales has its own provisions for overheating in new residential buildings. While the general approach is similar to England (limiting solar gains, providing means to remove excess heat), the specific simplified method parameters and thresholds may differ. Check the Welsh edition of Part O.

Part S — EV Charging Infrastructure

Wales has adopted EV charging requirements for new buildings but the specific provisions (number of charge points, cable routes) may differ from England. Check the Welsh edition for current requirements.

Approved Documents — Wales Editions

Building Control Process in Wales

The Building Control process in Wales is essentially the same as England:

• Full Plans: Submit detailed plans and specifications. Decision within 5 weeks (extendable to 2 months).
• Building Notice: Notify at least 2 working days before starting work. No formal plan approval.
• Approved Inspectors: Private sector Building Control is available as an alternative to the local authority.
• Competent person schemes: All major schemes (FENSA, Gas Safe, NICEIC, etc.) operate in Wales.
• Completion certificates: Issued by Building Control on satisfactory completion of work.

SAP Calculations in Wales

The Standard Assessment Procedure (SAP) is used in Wales for energy performance calculations, as in England. However, the target emission rate (TER) and dwelling emission rate (DER) targets differ between the Welsh and English editions of Part L. If you are using SAP software, ensure it is set to the Welsh regulatory regime rather than the English one. The fabric energy efficiency standard (FEES) targets also differ. An energy assessor familiar with Welsh requirements should be used for SAP calculations on Welsh projects.

Key Resources

• Welsh Government — Building Regulations — Official Welsh building regulations guidance and Approved Documents
• Planning Portal — Wales — Building regulations information for Wales

Related Calculators

Our Part L Compliance Calculator uses English U-value targets — for Welsh projects, check the Welsh edition of Part L for any differences in backstop values. The Building Control Fee Calculator provides estimates that are broadly applicable to Welsh local authorities. Other calculators such as the Part B Fire Strategy Calculator and Part K Stair Calculator apply equally in Wales where the same Approved Documents are used.

For regulations in other parts of the UK, see our guides for England, Scotland and Northern Ireland.