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Knowledge Centre · Technical design
Building Regulations Explained
Building Regulations set minimum standards for the design and construction of buildings. They are separate from planning permission and cover matters such as structure, fire safety, insulation, ventilation, drainage, glazing and electrical safety.
General guidance for EnglandLast reviewed 27 July 2026
What are Building Regulations?
Building Regulations are legal requirements for building work in England. They establish minimum standards for health, safety, welfare, accessibility, energy and other aspects of design and construction.
They apply to many extensions, conversions, structural alterations, material changes of use and new buildings. Compliance depends on the specific work and property. Building Control approval does not remove the need for planning permission, listed building consent, Party Wall procedures, drainage agreements, licences or private consents.
Planning permission and Building Regulations are different
Building Regulations
- Structure and fire safety
- Energy efficiency and ventilation
- Drainage and sanitation
- Access, stairs, guarding and glazing
- Electrical safety and construction standards
A planning approval does not confirm that the construction complies with Building Regulations, and Building Control approval does not establish that planning permission exists.
Read Planning Permission ExplainedWhen do Building Regulations apply?
The answer depends on the work, existing building, use and any applicable exemptions or self-certification route. These examples identify common issues rather than giving a project-specific decision.
House extensions
New floorspace, foundations, structure, thermal performance, ventilation, drainage, glazing and fire safety commonly require coordinated assessment.
Loft conversions
Structure, stairs, headroom, protected escape routes, alarms, insulation, ventilation and the existing roof and floors are central considerations.
Garage conversions
The floor, walls, roof, moisture resistance, insulation, ventilation, fire separation and any structural changes may need to be addressed.
Structural wall removal and new openings
The load path, temporary works and permanent support require competent structural design and coordination with the surrounding construction.
New and replacement homes
The whole building must be coordinated across structure, fire, energy, ventilation, drainage, access, overheating, services and other applicable requirements.
HMOs and flat conversions
Changes of use and subdivision can trigger extensive fire, sound, ventilation, access, thermal and drainage requirements alongside other housing and licensing duties.
Commercial-to-residential and barn conversions
A material change of use can bring existing fabric, fire separation, energy, ventilation, structure, moisture, access and services within scope.
Drainage alterations
New or changed foul and surface-water systems, connections, build-over situations and work close to foundations may require technical approval and separate agreements.
Replacement windows and installations
Some replacement windows, electrical work, heating systems and other installations are controlled work, although an authorised competent person scheme may provide the compliance route.
How Building Regulations approval works
The correct building control body and application route depend on the building and work. Higher-risk building work follows a separate Building Safety Regulator process; the routes below describe the ordinary domestic and small residential context.
Local authority Building Control
For ordinary domestic and small residential work, the local authority can act as the building control body, assess the application and arrange inspections.
Registered building control approver
For eligible non-higher-risk work, a private registered building control approver can act as the building control body and give an initial notice to the local authority. “Approved inspector” is older terminology and should not be used for new appointments.
Full plans
Plans, specifications and supporting information are assessed before or alongside the start of work, creating a formal record of the proposed compliance approach.
Building notice
A building notice is generally intended for smaller, simpler work. It provides less design information for advance assessment and is not available for every project or circumstance.
Regularisation
A local authority may consider eligible unauthorised work completed after the relevant historic date. Opening-up and remedial work may be required, and a certificate is not automatic.
Competent person schemes
Registered installers can self-certify specified work, such as certain electrical, glazing or heating installations, and notify the authority through their authorised scheme.
Full plans application or building notice?
Full plans
Technical drawings and supporting information are submitted for assessment. This route is suited to more complex work, creates a formal review record and may reduce uncertainty before key construction decisions are made.
Building notice
Less information is provided at submission, which may suit simpler eligible work but leaves greater risk of technical issues being resolved during construction. It is not available for every project type.
Neither route guarantees compliance.
The design must be suitable and the work must be constructed correctly. Inspections and approvals do not transfer the dutyholders’ responsibilities to Building Control.
What is included in a Building Regulations drawing package?
The package should explain how the design is intended to satisfy the requirements relevant to the project. Typical architectural and coordinated information may include:
- Existing and proposed plans
- Sections and elevations where needed
- Construction build-ups
- Insulation and thermal information
- Structural openings, foundations and roof construction
- Floor construction
- Fire-safety measures
- Ventilation strategy
- Foul and surface-water drainage
- Glazing and safety glazing
- Stairs, guarding and accessibility
- Electrical safety notes
- Coordination with structural calculations
Structural calculations, energy assessments, fire engineering, acoustic testing, overheating analysis or other consultant information may also be needed. Their scope is project-specific.
What are the Approved Documents?
Approved Documents give statutory guidance on ways to meet the functional requirements of the Building Regulations. They provide common approaches, not a substitute for competent design or the only possible route to compliance.
Part A
Structure
Part B
Fire safety
Part C
Site preparation and resistance to contaminants and moisture
Part E
Resistance to sound
Part F
Ventilation
Part G
Sanitation, hot water safety and water efficiency
Part H
Drainage and waste disposal
Part J
Combustion appliances and fuel storage systems
Part K
Protection from falling, collision and impact
Part L
Conservation of fuel and power
Part M
Access to and use of buildings
Part O
Overheating
Part P
Electrical safety
Part Q
Security
Part R
Electronic communications infrastructure
Part S
Infrastructure for charging electric vehicles
Structure and foundations
Foundations must suit the ground, building loads and influences such as nearby trees, drains and adjacent structures. Existing foundations and walls may need assessment where new work relies on them.
Structural openings can require beams, posts or frames designed around a clear load path, stability, bearings and movement. Calculations are commonly prepared by a structural engineer and coordinated with the architectural design. Party Wall matters can arise separately and are not decided through Building Control.
Fire safety
Residential technical design can involve means of escape, fire-resisting construction, protected routes, alarms, fire doors, compartmentation, cavity barriers, separation between uses and—where relevant—access and facilities for the fire service.
HMOs and flat conversions can require additional coordination because Building Regulations sit alongside HMO licensing, housing legislation, the Fire Safety Order where applicable and fire-risk duties. Approval under one regime does not satisfy the others.
Energy efficiency and thermal performance
Walls, roofs, floors, windows and doors must achieve suitable thermal performance. Junctions, thermal bridging and air leakage can be as important as the headline insulation specification.
Extensions can affect the existing dwelling, especially where large areas of glazing are proposed. Additional assessment or compensating measures may be needed, and heating systems and controls may require upgrading. Part L requirements change over time, so current guidance must be used.
Ventilation and overheating
A ventilation strategy can combine background ventilation, local extract and whole-dwelling provision. Greater airtightness makes the coordination of indoor air quality and moisture control particularly important.
Large glazing areas and solar gain can increase overheating risk. Orientation, shading, openable areas and natural or mechanical ventilation should be considered together. Mechanical ventilation with heat recovery may be appropriate for some projects, but it requires careful design, installation and commissioning.
Drainage and below-ground services
Technical information may need to identify foul and surface-water routes, connection points, gradients, inspection chambers, soakaways and the relationship between drainage and foundations.
Building over or close to a public sewer can require a separate agreement with the water authority. Surface-water disposal, highway connections and other drainage approvals may also sit outside the Building Control application.
Stairs, guarding and accessibility
Stair geometry, headroom, landings, handrails and guarding must be developed as part of the spatial and structural design. Access to new rooms and the wider accessibility of the building may also be relevant.
Loft conversions are particularly constrained because the stair must fit within the existing house while coordinating headroom, structure, circulation and the fire-safety strategy.
Glazing and electrical safety
Glazing design can involve safety glass, guarding, thermal performance, ventilation openings and the risk of collision or falling. Large or low-level panes may need more than a standard window specification.
Part P applies to electrical safety in dwellings. Certain work can be self-certified by an installer registered with an authorised competent person scheme; other work follows the appropriate Building Control route. Electrical layouts should coordinate with structure, fire, ventilation and the architectural design.
What happens during Building Control approval?
- 01
Confirm the scope of work
Identify controlled work, exemptions, the building type and the appropriate approval route.
- 02
Prepare survey information
Record the existing building accurately enough to coordinate the proposed construction.
- 03
Develop technical drawings
Set out the design, build-ups and compliance strategy at a proportionate level of detail.
- 04
Coordinate structural information
Integrate the engineer’s calculations and details with the architectural package.
- 05
Submit the application
Provide the selected building control body with the required application information.
- 06
Respond to technical comments
Clarify or revise the design where the reviewer identifies missing information or concerns.
- 07
Give the correct notices
Before and during construction, submit the commencement and other notifications required for the chosen route.
- 08
Arrange inspections
Notify Building Control at the project-specific stages they ask to inspect.
- 09
Resolve site queries
Review proposed changes before work is concealed or departs from the accepted design.
- 10
Obtain completion documentation
Arrange the final inspection and supply certificates, declarations and other required evidence.
Inspection is not site supervision.
Building Control inspections are proportionate checks at selected stages. They do not replace the contractor’s responsibility for compliant construction or the project’s own quality-control and contract-administration arrangements.
What does Building Control inspect?
The required inspection plan depends on the work and risks. Common notification or inspection stages can include:
- Commencement
- Excavations
- Foundations
- Damp-proof course
- Drainage
- Structural work
- Insulation
- Fire-safety measures
- Roof construction
- Completion
The building control body should confirm the stages for the particular project. Work should not be concealed before a required inspection.
Why the completion certificate matters
A completion certificate records that the building control body has completed its process and, having taken reasonable steps, is satisfied about compliance. Solicitors, buyers and lenders may request it during a sale or refinancing.
The certificate does not guarantee every aspect of workmanship or confirm that every concealed detail was inspected. Missing final inspections, declarations, test certificates or other information can delay its issue and create future difficulties.
Common residential project considerations
House extensions
Foundations, structure, existing openings, insulation, glazing, ventilation, drainage and the relationship with the original house need to work as one technical proposal.
Loft conversions
Existing roof and floor structure, stair geometry, fire-protected escape, alarms, insulation, ventilation and junction detailing are usually decisive.
Garage conversions
The existing slab, damp resistance, wall and roof performance, fire separation, ventilation, services and openings should be assessed rather than assumed.
New homes
A coordinated whole-building strategy is needed for structure, fire, energy, overheating, ventilation, water, drainage, access, security and services.
HMOs
Building Regulations overlap with—but do not replace—HMO licensing, housing standards and fire-risk duties. Occupancy and layout affect the technical strategy.
Flat conversions
Compartmentation, sound insulation, escape, smoke detection, ventilation, drainage, access and service penetrations require careful coordination.
Barn conversions
The existing structure, ground conditions, moisture, thermal upgrading, ventilation, ecology-related constraints and new services can make the technical design unusually interdependent.
Commercial-to-residential conversions
The material change of use may require the retained building to meet specified requirements for fire, sound, ventilation, energy, access and sanitation.
Common Building Regulations mistakes to avoid
- Confusing planning approval with Building Regulations approval
- Starting controlled work without the correct application or notice
- Relying on planning drawings as construction information
- Failing to coordinate structural calculations with the architectural design
- Changing the design on site without technical review
- Covering foundations, structure, insulation or drainage before inspection
- Omitting a coordinated ventilation strategy
- Underestimating fire-safety requirements
- Ignoring drainage routes, levels or third-party agreements
- Failing to arrange the final inspection and completion certificate
- Assuming builder experience replaces competent technical design
Technical design support from Hepburn Architects
Hepburn Architects can develop approved concepts into coordinated technical information for residential Building Regulations applications. The practice can assist with:
- Measured surveys
- Technical plans, sections and construction details
- Building Regulations applications
- Coordination with structural engineers
- Fire and ventilation strategy coordination
- Drainage layouts
- Extension and loft-conversion packages
- HMO and residential conversion technical design
- Responses to Building Control comments
Site project management and continuous site supervision are not included unless a separate construction-stage service is expressly agreed.
View Building Regulations ServicesSelected work
Projects requiring coordinated technical design
Residential projects selected dynamically across extensions, new homes and conversions.
House Extension Solihull
Traditional Barn conversion Northumberland
New Build Apartments Cornwall
Contemporary Renovation Shropshire
Replacement Bungalow
Modern Extension to Rural Property
Questions and answers
Building Regulations FAQs
General answers for residential work in England. A specific project still requires an appropriate technical and approval review.
Do I need Building Regulations approval for an extension?
Most house extensions contain controlled building work and require an appropriate Building Control route. The exact requirements depend on the extension, existing building, construction and services. Planning permission, Party Wall procedures and drainage agreements are separate matters.
Are planning permission and Building Regulations the same?
No. Planning considers whether development is acceptable in land-use and design terms. Building Regulations set legal requirements for design and construction, including structure, fire safety, energy, ventilation, drainage and access. A project may need one, both or neither formal application depending on the work.
Do I need Building Regulations for a loft conversion?
A habitable loft conversion normally involves controlled work. Structure, stairs, protected escape, alarms, insulation, ventilation and other requirements need project-specific coordination. A simple boarding-out exercise is different from creating a room.
Do I need approval to remove a loadbearing wall?
Removing or altering a loadbearing wall is controlled structural work. A competent structural design is commonly required for the permanent support, bearings and load path, and Building Control will normally need to be notified through the appropriate route.
Can I use planning drawings for Building Regulations?
Planning drawings rarely contain enough technical information. They focus on appearance and planning impacts, whereas a Building Regulations package needs construction build-ups and coordinated information about structure, fire, energy, ventilation, drainage and other applicable requirements.
What is a full plans application?
A full plans application provides drawings and supporting information for assessment by the building control body. It creates a formal review record before or during the early construction stage, but approval does not remove the need to build compliantly and arrange inspections.
What is a building notice?
A building notice is a less detailed submission route generally intended for smaller work. There is no equivalent advance approval of detailed plans, so more issues may need resolution during construction. It is not available for every project or situation.
Who checks Building Regulations work?
For ordinary non-higher-risk work in England, the building control body is usually the local authority or a registered building control approver. Registered building inspectors advise building control bodies by assessing plans and inspecting work. The Building Safety Regulator is the building control authority for higher-risk building work.
Do I need a structural engineer?
Many extensions, loft conversions, wall removals and conversions need structural calculations and details. Whether an engineer is required depends on the proposed work, existing construction, ground conditions and structural complexity.
What happens if Building Control finds a problem?
The design or construction may need clarification, additional evidence, opening-up or remedial work. The client, designers and contractors should coordinate an acceptable solution before affected work is concealed or progressed.
Can I sell a house without a completion certificate?
A sale may still be possible, but missing completion documentation can prompt solicitor, lender and buyer questions. The appropriate response depends on the work, records and legal circumstances; retrospective Building Control or legal advice may be needed.
Can unauthorised work be regularised?
Eligible historic work may be considered by a local authority through regularisation. Opening-up and remedial work may be required to demonstrate compliance, and approval is not guaranteed. Planning enforcement and other consents remain separate.
Does a Building Control inspection guarantee workmanship?
No. Building Control uses proportionate plan assessment and risk-based inspections; it does not act as a clerk of works or inspect every detail. Inspections and certificates do not replace the legal responsibilities of clients, designers and contractors or a suitable quality-control process.
Who is responsible for compliance?
Responsibility is shared through statutory dutyholder roles. Clients must make suitable arrangements and appoint competent people; designers must take reasonable steps to produce compliant designs; contractors must carry out compliant work. Building Control independently assesses and inspects but does not take over those duties.
Primary references
Official Building Regulations guidance
These official sources were reviewed when preparing this guide. Regulations and guidance change, so use the current source for any project-specific decision.
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