Building Regulations Approval in London: A Complete Homeowner's Guide 2025

ALMOST ALL SIGNIFICANT BUILDING WORK IN LONDON REQUIRES BUILDING REGULATIONS APPROVAL. COMMON WORKS THAT REQUIRE APPROVAL:

STRUCTURAL WORKS: — ANY EXTENSION (SINGLE OR DOUBLE STOREY) — LOFT CONVERSIONS — GARAGE CONVERSIONS — BASEMENT CONVERSIONS — REMOVAL OF LOAD-BEARING WALLS — STRUCTURAL OPENINGS (INSTALLING STEELS FOR BIFOLD DOORS, KNOCKTHROUGHS, ETC.) — UNDERPINNING OR SIGNIFICANT ALTERATION TO FOUNDATIONS

MECHANICAL AND ELECTRICAL WORKS: — NEW BOILER INSTALLATION (MUST BE COMMISSIONED BY A GAS SAFE REGISTERED ENGINEER — SELF-CERTIFIED NOTIFICATION TO BUILDING CONTROL) — ELECTRICAL INSTALLATION IN A BATHROOM, KITCHEN, OR NEW CIRCUIT (MUST BE CERTIFIED BY A PART P QUALIFIED ELECTRICIAN — SELF-CERTIFIED OR BUILDING CONTROL APPROVAL) — INSTALLATION OF ADDITIONAL ELECTRICAL CONSUMER UNIT (FUSE BOARD) — BUILDING CONTROL NOTIFICATION

FIRE SAFETY WORKS: — INSTALLING OR REMOVING FIRE DOORS (FD30S, FD60S) — LOFT CONVERSIONS TRIGGERING GRADE D LD2 SMOKE ALARM SYSTEM UPGRADE — CONVERTING A PROPERTY INTO MULTIPLE DWELLINGS (PART B FIRE STRATEGY REQUIRED)

ENERGY EFFICIENCY WORKS: — REPLACEMENT WINDOWS AND DOORS: MUST MEET PART L U-VALUE REQUIREMENTS (1.4 W/M2K) — EITHER FENSA/CERTASS CERTIFIED INSTALLER (SELF-CERTIFIES) OR BUILDING CONTROL APPLICATION — NEW ROOF (FLAT OR PITCHED): MUST MEET PART L INSULATION STANDARDS — EXTENSIONS: MUST ACHIEVE PART L ENERGY COMPLIANCE FOR WALLS, ROOF, FLOOR, AND GLAZED ELEMENTS

WORKS THAT DO NOT REQUIRE BUILDING REGULATIONS: — LIKE-FOR-LIKE REPAIRS (E.G. REPLACING INDIVIDUAL SLATES, REPOINTING, INTERNAL DECORATION) — SMALL TIMBER OUTBUILDINGS (UNDER 15M2 DETACHED, WITH NO SLEEPING ACCOMMODATION) — GARDEN WALLS BELOW CERTAIN HEIGHTS

THERE ARE TWO PRIMARY ROUTES FOR OBTAINING BUILDING REGULATIONS APPROVAL FOR BUILDING WORK IN LONDON:

FULL PLANS APPLICATION (RECOMMENDED FOR MOST PROJECTS): A FULL PLANS APPLICATION INVOLVES SUBMITTING DETAILED DRAWINGS, SPECIFICATIONS, AND SUPPORTING CALCULATIONS TO THE BUILDING CONTROL BODY (BCB) BEFORE WORK COMMENCES. THE BCB CHECKS THE PLANS AND ISSUES A FORMAL APPROVAL (FULL PLANS APPROVAL). WORK CAN THEN PROCEED KNOWING THE DESIGN HAS BEEN CHECKED IN ADVANCE.

ADVANTAGES OF FULL PLANS: — DESIGN IS CHECKED BEFORE WORK STARTS — ERRORS ARE CAUGHT EARLY (BEFORE EXPENSIVE REMEDIATION IS REQUIRED) — PROVIDES CERTAINTY FOR THE CONTRACTOR AND THE HOMEOWNER — REQUIRED FOR CERTAIN TYPES OF WORK (EXTENSIONS OVER CERTAIN SIZE, ALL STRUCTURAL ALTERATIONS) — EASIER TO SELL THE PROPERTY — SOLICITORS HAVE APPROVED PLANS ON FILE

TIMELINE: 5-6 WEEKS FOR BCB TO EXAMINE AND APPROVE FULL PLANS (STATUTORY MAXIMUM)

FEE: VARIES BY LONDON BOROUGH — TYPICALLY: — SINGLE-STOREY REAR EXTENSION (UP TO 40M2): £700-£1,200 — LOFT CONVERSION: £900-£1,500 — TWO-STOREY REAR EXTENSION: £900-£1,400

BUILDING NOTICE: A BUILDING NOTICE IS A SIMPLER NOTIFICATION THAT YOU INTEND TO CARRY OUT WORK THAT REQUIRES BUILDING REGULATIONS APPROVAL. NO PLANS ARE SUBMITTED IN ADVANCE — WORK BEGINS AND THE BCB INSPECTOR CHECKS COMPLIANCE AT EACH STAGE.

ADVANTAGES OF BUILDING NOTICE: — FASTER START: NO WAITING FOR PLANS APPROVAL — LOWER INITIAL COST (PLAN CHECK FEE ELEMENT NOT APPLICABLE)

DISADVANTAGES OF BUILDING NOTICE: — NO PRE-CHECK OF DESIGN — ERRORS DISCOVERED DURING CONSTRUCTION — CANNOT BE USED FOR ALL WORK TYPES: NOT SUITABLE FOR COMPLEX STRUCTURAL WORKS OR HIGHER-RISK BUILDINGS — IF INSPECTOR REQUIRES CHANGES, COMPLETED WORK MAY NEED TO BE OPENED UP OR DEMOLISHED — SELLING SOLICITORS OFTEN REQUEST RETROSPECTIVE PLANS — WHICH MUST BE DRAWN UP LATER

GENERAL RECOMMENDATION FOR LONDON HOMEOWNERS: USE FULL PLANS FOR ANY STRUCTURAL WORK, EXTENSIONS, OR LOFT CONVERSIONS. BUILDING NOTICE IS SUITABLE FOR SMALLER, WELL-UNDERSTOOD WORKS WHERE A COMPETENT CONTRACTOR IS CERTAIN OF COMPLIANCE.

SINCE THE DEREGULATION OF BUILDING CONTROL IN 1985, HOMEOWNERS AND DEVELOPERS HAVE HAD A CHOICE OF BUILDING CONTROL BODY (BCB):

LOCAL AUTHORITY BUILDING CONTROL (LABC): EACH LONDON BOROUGH HAS ITS OWN BUILDING CONTROL TEAM (E.G. CAMDEN BUILDING CONTROL, ISLINGTON BUILDING CONTROL, WANDSWORTH BUILDING CONTROL). LABC INSPECTORS ARE EMPLOYED BY THE COUNCIL. FEES ARE SET BY THE BOROUGH. LABC IS THE DEFAULT CHOICE AND IS OFTEN MOST SUITABLE FOR HOMEOWNER PROJECTS.

APPROVED INSPECTORS (AI): PRIVATE COMPANIES LICENSED BY THE BUILDING SAFETY REGULATOR (BSR) TO CARRY OUT BUILDING CONTROL FUNCTIONS. APPROVED INSPECTORS ARE TYPICALLY USED BY DEVELOPERS AND CONTRACTORS FOR LARGER PROJECTS. FOR HOMEOWNERS, APPROVED INSPECTORS CAN BE MORE FLEXIBLE IN SCHEDULING INSPECTIONS — BUT FEES MAY BE HIGHER THAN LABC.

NEW REQUIREMENT FROM 2024 (BUILDING SAFETY ACT 2022): THE BUILDING SAFETY ACT 2022 CHANGED THE REGULATORY LANDSCAPE SIGNIFICANTLY: — ALL NEW BUILDINGS OVER 18 METRES (7+ STOREYS) MUST USE THE NEW NATIONAL REGULATOR (HEALTH AND SAFETY EXECUTIVE) AS BCB — NOT LABC OR APPROVED INSPECTORS — APPROVED INSPECTORS ARE NOW RENAMED "REGISTERED BUILDING CONTROL APPROVERS" (RBCAs) AND MUST BE REGISTERED WITH THE BUILDING SAFETY REGULATOR — FOR RESIDENTIAL SINGLE-FAMILY HOUSES IN LONDON: LABC REMAINS THE DEFAULT AND APPROPRIATE BCB FOR ALL STANDARD HOME EXTENSIONS AND CONVERSIONS

CHOOSING YOUR BCB: FOR MOST LONDON HOMEOWNER PROJECTS: 1. CONTACT YOUR BOROUGH'S LABC TEAM DIRECTLY 2. SUBMIT FULL PLANS APPLICATION WITH YOUR ARCHITECT'S DRAWINGS AND STRUCTURAL ENGINEER'S CALCULATIONS 3. RECEIVE PLAN APPROVAL (5-6 WEEKS) 4. COMMENCE WORKS AND REQUEST STAGE INSPECTIONS

DURING BUILDING WORK, THE BUILDING CONTROL INSPECTOR (BCO) WILL VISIT THE SITE AT KEY STAGES TO CHECK COMPLIANCE WITH THE APPROVED PLANS AND BUILDING REGULATIONS.

STANDARD INSPECTION STAGES FOR A LONDON REAR EXTENSION:

1. COMMENCEMENT (NOTIFICATION ONLY): NOTIFY THE BCB WHEN WORK COMMENCES. THE INSPECTOR MAY VISIT AT THIS POINT TO REVIEW THE SITE.

2. FOUNDATIONS (TRENCH INSPECTION): BEFORE CONCRETE IS POURED INTO THE FOUNDATION TRENCHES — THE BCO CHECKS DEPTH, WIDTH, AND SOIL CONDITIONS. DO NOT POUR CONCRETE WITHOUT BCO APPROVAL.

3. OVERSITE (BEFORE SLAB POUR): INSPECTION OF THE DPM, INSULATION, AND REINFORCEMENT BEFORE THE GROUND FLOOR SLAB IS POURED.

4. DAMP-PROOF COURSE (DPC) LEVEL: INSPECTION OF THE DPC POSITION AND THE CAVITY TRAY AT DOOR AND WINDOW THRESHOLDS.

5. STEELWORK (STRUCTURAL BEAM INSPECTION): IF STRUCTURAL STEELWORK IS INVOLVED (BIFOLD DOOR BEAM, KNOCKTHROUGH BEAM): BCO MUST INSPECT STEELWORK IN PLACE BEFORE IT IS BUILT IN OR BOARDED.

6. FRAME (IF TIMBER FRAME EXTENSION): INSPECTION OF STRUCTURAL TIMBER FRAME BEFORE INSULATION AND PLASTERBOARD COVER.

7. ROOF STRUCTURE: ROOF TIMBERS AND FLAT ROOF STRUCTURE INSPECTED BEFORE COVERING.

8. INSULATION: INSULATION IN WALLS, FLOOR, AND ROOF INSPECTED BEFORE PLASTERBOARDING.

9. DRAINAGE: DRAINAGE WORKS INSPECTED BEFORE BACKFILLING.

10. COMPLETION (FINAL INSPECTION): FINAL INSPECTION WHEN ALL WORKS ARE COMPLETE. THE BCO ISSUES A COMPLETION CERTIFICATE (OR FINAL CERTIFICATE FROM AN APPROVED INSPECTOR) IF ALL WORKS COMPLY.

COMPLETION CERTIFICATE — CRITICAL FOR PROPERTY SALE: THE COMPLETION CERTIFICATE CONFIRMS THAT ALL NOTIFIED BUILDING WORK HAS BEEN INSPECTED AND FOUND TO COMPLY WITH BUILDING REGULATIONS. WITHOUT A COMPLETION CERTIFICATE, SOLICITORS WILL RAISE A REQUISITION ON SALE — OFTEN REQUIRING INSURANCE (INDEMNITY INSURANCE — TYPICALLY £200-£500 PER PROPERTY) OR A REGULARISATION APPLICATION TO BUILDING CONTROL. NEVER PROCEED WITHOUT A COMPLETION CERTIFICATE — PARTICULARLY FOR STRUCTURAL WORKS.

IF BUILDING WORK HAS BEEN CARRIED OUT WITHOUT BUILDING REGULATIONS APPROVAL IN A LONDON PROPERTY (A COMMON DISCOVERY DURING CONVEYANCING ON OLDER PROPERTIES), THERE ARE TWO MAIN REMEDIATION OPTIONS:

REGULARISATION APPLICATION: A REGULARISATION APPLICATION ALLOWS THE LABC (LOCAL AUTHORITY BUILDING CONTROL) TO RETROSPECTIVELY INSPECT AND CERTIFY BUILDING WORK THAT WAS COMPLETED WITHOUT APPROVAL. THE PROCESS: 1. SUBMIT A REGULARISATION APPLICATION TO THE LABC (NOT AVAILABLE WITH APPROVED INSPECTORS FOR RETROSPECTIVE WORK) 2. BCO INSPECTS THE COMPLETED WORK — SOME OPENING-UP OF COMPLETED ELEMENTS MAY BE REQUIRED 3. IF COMPLIANT, BCO ISSUES A REGULARISATION CERTIFICATE FEE: TYPICALLY 1.5X THE STANDARD FULL PLANS FEE (E.G. £1,050-£1,800 FOR A REAR EXTENSION) LIMITATION: ONLY AVAILABLE FOR WORK COMPLETED AFTER NOVEMBER 1985.

INDEMNITY INSURANCE: AN ALTERNATIVE TO REGULARISATION — AN INSURANCE POLICY THAT PROTECTS THE BUYER AND LENDER AGAINST THE RISK OF ENFORCEMENT ACTION BY THE LPA FOR THE ABSENCE OF BUILDING REGULATIONS APPROVAL. TYPICALLY USED WHERE: — WORKS WERE MINOR AND RISK OF ENFORCEMENT IS LOW — PROPERTY HAS CHANGED HANDS MULTIPLE TIMES SINCE WORKS — REGULARISATION IS IMPRACTICAL (E.G. ELEMENTS NOW COVERED AND INACCESSIBLE) COST: £200-£500 ONE-OFF PREMIUM, FIXED AMOUNT OF INDEMNITY COVER.

PRACTICAL ADVICE: IF BUYING A LONDON PROPERTY WITH RECENT EXTENSIONS OR ALTERATIONS, ALWAYS REQUEST BUILDING REGULATIONS COMPLETION CERTIFICATES AS PART OF THE CONVEYANCING PROCESS. YOUR SOLICITOR SHOULD RAISE ENQUIRIES — BUT DO NOT RELY ON THIS ALONE. IF CERTIFICATES ARE MISSING, RAISE THE ISSUE BEFORE EXCHANGE (NOT AFTER), AND REQUIRE EITHER A REGULARISATION CERTIFICATE OR SUITABLE INDEMNITY INSURANCE AS A CONDITION OF PURCHASE.