What This Requirement Covers
A material change of use occurs when a building's use changes in a way that triggers Building Regulations requirements. Regulation 5 of the Building Regulations 2010 defines the circumstances that constitute a material change of use. The key principle is that when a building changes to a more demanding use (in terms of fire safety, structural adequacy, or other requirements), it must be brought up to current standards for those requirements.
Key Requirements
What Constitutes a Material Change of Use
A material change of use occurs when a building or part of a building that was previously used for one purpose is used for another, including
- A building becomes a dwelling or contains a flat for the first time
- A building becomes a hotel, boarding house, or institution
- A building becomes a public building
- A building is not a building to which the Regulatory Reform (Fire Safety) Order 2005 applies and becomes one
- A building contains a greater or lesser number of dwellings than it did previously
What Standards Apply (Regulation 6)
On a material change of use, the building must comply with the following requirements as if the work were new building work
- Part A (Structure): To the extent necessary for the safety of the building in its new use
- Part B (Fire Safety): Fully, for the new use and building classification
- Part C (Moisture): For any work involving external walls or floors
- Part E (Sound): For separating walls and floors between dwellings
- Part F (Ventilation): For the new use
- Part L (Energy): Thermal elements that are being retained must meet at least the renovation standards; new elements must meet new-build standards
- Part M (Access): Depending on the new use and building type
- Part P (Electrical): For dwellings
Common Changes of Use
- Office to residential (Class E to Class C3): Permitted development under Class MA of the GPDO, but full Building Regulations compliance is required
- Shop to restaurant (Class E to Class E): May not be a material change of use for Building Regulations purposes if the use class has not changed, but specific works may trigger requirements
- Warehouse to residential (Class B8 to Class C3): Material change of use; full Building Regulations compliance required
- House to HMO (Class C3 to Class C4 or sui generis): May require Building Regulations compliance if works are needed
- Barn to dwelling (agricultural to Class C3): Material change of use; full compliance required
Practical Compliance Tips
- Determine whether the proposed change of use is a material change of use under Regulation 5 before starting design
- Commission a building survey to identify the extent of work needed to bring the building up to current standards
- Fire safety is usually the most significant and costly area of compliance in change of use conversions
- Sound insulation between dwellings in conversions is tested to the same standards as new-build (Approved Document E)
- Energy performance standards for thermal elements apply to the renovation standard, not the new-build standard (unless the element is being newly constructed)
- Submit a full plans application to Building Control with details of how each applicable requirement will be met
- For office-to-residential conversions under permitted development, do not assume that the building already complies; most offices need significant work to meet residential fire, sound, and thermal standards