Orangeries in London: Design, Planning, Glazing & Cost Guide 2025

THE THREE CATEGORIES ARE OFTEN CONFUSED IN THE RESIDENTIAL MARKET:

CONSERVATORY: DEFINED BY PLANNING POLICY AND BUILDING REGULATIONS: A STRUCTURE WHERE MORE THAN 75% OF THE ROOF AND MORE THAN 50% OF THE WALLS ARE GLAZED. UNTIL RELATIVELY RECENTLY, CONSERVATORIES WERE EXEMPT FROM THERMAL COMPLIANCE UNDER PART L — THIS EXEMPTION HAS NOW BEEN REMOVED (SINCE 2021 NOTIONAL BUILDING SPECIFICATION) FOR NEW CONSERVATORIES NOT SEPARATED BY A DOOR FROM THE HEATED DWELLING. A STANDARD POLYCARBONATE-ROOFED CONSERVATORY IS HOT IN SUMMER, COLD IN WINTER, AND TYPICALLY USABLE ONLY IN MILD WEATHER.

EXTENSION: A SOLID BRICK AND BLOCK OR STRUCTURAL FRAME BUILDING WITH STANDARD FENESTRATION (WINDOWS AND DOORS). THERMALLY COMFORTABLE YEAR-ROUND BUT LACKS THE LIGHT AND GARDEN-CONNECTION QUALITY OF A GLAZED STRUCTURE.

ORANGERY: THE RESIDENTIAL ORANGERY SITS BETWEEN THESE TWO — TYPICALLY: — SOLID BRICK WALLS (CAVITY CONSTRUCTION TO PART L STANDARDS: LONDON STOCK BRICK OR RENDER OUTER LEAF + INSULATED CAVITY + INNER BLOCKWORK LEAF) — SUBSTANTIAL FRONT GLAZING (BIFOLD OR SLIDING DOORS) AND LARGE SIDE WINDOWS — PARTLY SOLID FLAT ROOF WITH A GLAZED LANTERN OR LARGE GLASS ROOFLIGHT SECTION AT THE CENTRE — THE SOLID ROOF SECTIONS (TYPICALLY INSULATED FLAT ROOF, U-VALUE 0.15 W/M2K) PROVIDE THERMAL BUFFER — THE LANTERN PROVIDES LIGHT WITHOUT THE FULL EXTENT OF A CONSERVATORY'S OVERHEATING AND HEAT LOSS

THE RESULT: A SPACE THAT IS USABLE YEAR-ROUND (SUITABLE FOR PART L THERMAL COMPLIANCE AS A HEATED HABITABLE ROOM), HAS EXCEPTIONAL LIGHT FROM THE LANTERN AND BIFOLD DOORS, AND FEELS ARCHITECTURALLY COMPLETE IN A WAY A CONSERVATORY OFTEN DOES NOT.

PLANNING REQUIREMENTS FOR AN ORANGERY IN LONDON DEPEND ON SIZE, LOCATION, AND WHETHER THE PROPERTY BENEFITS FROM PERMITTED DEVELOPMENT RIGHTS.

PERMITTED DEVELOPMENT (CLASS A — REAR EXTENSION): AN ORANGERY ON THE REAR ELEVATION CAN POTENTIALLY QUALIFY AS PERMITTED DEVELOPMENT IF IT MEETS ALL GPDO 2015 CLASS A CRITERIA: — NOT TALLER THAN THE RIDGELINE OF THE ORIGINAL HOUSE — SINGLE STOREY: MAXIMUM EAVES HEIGHT 3.0M (4.0M ON DETACHED HOUSE); MAXIMUM HEIGHT 4.0M (4.0M ON DETACHED) — MAXIMUM DEPTH FROM ORIGINAL REAR WALL: - DETACHED HOUSE: 4.0M (OR UP TO 8.0M WITH PRIOR APPROVAL) - SEMI-DETACHED OR TERRACED: 3.0M (OR UP TO 6.0M WITH PRIOR APPROVAL) — DOES NOT PROJECT BEYOND THE SIDE ELEVATION — IN NON-ARTICLE 4 AREA AND NOT IN CONSERVATION AREA

CAVEAT: THE ORANGERY'S ROOF GLAZING (LANTERN) CAN SOMETIMES CAUSE ISSUES WITH THE "4M HEIGHT RULE" — IF THE LANTERN RAISES THE OVERALL HEIGHT ABOVE 4.0M, PD MAY NOT APPLY. ALWAYS CONFIRM WITH THE LPA BEFORE RELYING ON PD.

IN CONSERVATION AREAS: CONSERVATORIES AND ORANGERIES IN CONSERVATION AREAS ARE SPECIFICALLY EXCLUDED FROM PERMITTED DEVELOPMENT (GPDO 2015 CLASS B). A FULL HOUSEHOLDER PLANNING APPLICATION IS REQUIRED (FEE £258). DESIGN QUALITY IS CRITICAL — GLAZED LANTERN DESIGN, BRICK MATCHING, AND PROPORTION ARE ALL SCRUTINISED. PRE-APPLICATION ADVICE (£300-£600) IS STRONGLY RECOMMENDED.

BUILDING REGULATIONS: AN ORANGERY IS A HEATED, THERMALLY COMPLIANT HABITABLE SPACE AND MUST COMPLY FULLY WITH BUILDING REGULATIONS PARTS A (STRUCTURE), B (FIRE), F (VENTILATION), L (ENERGY EFFICIENCY), AND PART P (ELECTRICS). UNLIKE A CONSERVATORY, THERE IS NO BUILDING REGULATIONS EXEMPTION — FULL PLAN APPLICATION REQUIRED.

THE LANTERN ROOF IS THE DEFINING ARCHITECTURAL ELEMENT OF THE RESIDENTIAL ORANGERY — AND THE COMPONENT WHERE QUALITY VARIES MOST DRAMATICALLY IN THE MARKET.

STRUCTURAL ALUMINIUM LANTERN ROOF SYSTEMS:

FOURTEEN DEGREE ALUMINIUM LANTERN (BESPOKE OR SYSTEM): THE MOST COMMON RESIDENTIAL ORANGERY LANTERN FORM — A RECTANGULAR HIPPED OR PYRAMID ROOF STRUCTURE WITH FOUR SLOPING GLAZED FACES AND AN ALUMINIUM FRAME GRID. GLAZING: PILKINGTON OPTITHERM S3 PLUS 28MM OR 36MM DOUBLE GLAZED UNITS (U-VALUE 1.0-1.1 W/M2K CENTRE-PANE). FRAME MANUFACTURERS: — ULTRAFRAME (UK): ORANGERY ROOF SYSTEM WITH GLASS-ON-GLASS CORNER AND ALUMINIUM FRAME. MOST WIDELY INSTALLED IN UK RESIDENTIAL MARKET. — ELEMENT (UK): THERMALLY BROKEN ALUMINIUM LANTERN SYSTEM WITH SOLAR CONTROL GLASS OPTION. — KORNICHE (UK): PREMIUM ALUMINIUM LANTERN RANGE (KORNICHE LANTERN ROOF — 45° OR 25° PITCH) — MARKET-LEADING THERMAL PERFORMANCE: U=0.7 W/M2K WITH TRIPLE GLAZED UNIT. — ATLAS ROOF (UK): ATLAS UNI ROOF LANTERN SYSTEM — ALUMINIUM-CLAD INTERNALLY WITH TIMBER REVEAL OPTION.

GLAZING SPECIFICATION FOR LANTERNS: — SOLAR CONTROL: SOUTH-FACING LANTERNS SHOULD SPECIFY SOLAR CONTROL GLASS (PILKINGTON SUNCOOL 70/40, GUARDIAN SOLAR, OR SAINT-GOBAIN SGG CLIMAPLUS SOLAR CLEAR) TO REDUCE SUMMER OVERHEATING — THE MOST COMMON COMPLAINT WITH ORANGERY SPACES — SELF-CLEANING: PILKINGTON ACTIV GLASS WITH PHOTOCATALYTIC TIO2 COATING — STRONGLY RECOMMENDED FOR OVERHEAD GLAZING (DIFFICULT TO ACCESS FOR CLEANING) — SECURITY GLASS: WHERE LANTERN GLAZING IS WITHIN REACH FROM OUTSIDE, LAMINATED GLASS IS REQUIRED UNDER PART Q (RESISTANCE TO UNAUTHORIZED ACCESS)

FLAT ROOF SECTION (SOLID ROOF SECTIONS AROUND LANTERN): INSULATED FLAT ROOF WITH SARNAFIL G410 PVC OR EPDM MEMBRANE. PIR INSULATION: CELOTEX GA4000 150MM BETWEEN AND BELOW RAFTERS (WARM ROOF CONFIGURATION) — U-VALUE TARGET 0.15 W/M2K TO PART L. INTERNAL FINISH: WHITE PAINTED PLASTERBOARD CEILING WITH LED DOWNLIGHTS.

ONE OF THE MAIN DIFFERENTIATORS OF AN ORANGERY OVER A CONSERVATORY IS THAT AN ORANGERY IS DESIGNED AS A THERMALLY COMPLIANT, YEAR-ROUND HABITABLE ROOM. THIS REQUIRES ATTENTION TO HEATING, INSULATION, AND VENTILATION.

HEATING OPTIONS FOR ORANGERIES:

1. UNDERFLOOR HEATING (UFH): THE PREFERRED HEATING SOLUTION FOR ORANGERIES — UNDERFLOOR HEATING PROVIDES EVEN, COMFORTABLE WARMTH ACROSS THE FULL FLOOR AREA WITHOUT VISIBLE RADIATORS THAT WOULD INTERRUPT THE GLAZED APPEARANCE. NU-HEAT LOOPSTRATE OR UPONOR MLCP PIPE IN HANSON CEMFLOOR 65MM LIQUID SCREED. OUTPUT: 70-100 W/M2 REQUIRED FOR ORANGERY SPACE (HIGHER THAN A STANDARD ROOM GIVEN GLAZED AREA). POWERED BY EXISTING BOILER OR HEAT PUMP.

2. ELECTRIC UNDERFLOOR HEATING: FOR SMALLER ORANGERIES (UNDER 20M2): WARMUP STICKY MAT OR NUHEAT ELEMENT ELECTRIC UNDERFLOOR HEATING MAT UNDER PORCELAIN OR NATURAL STONE TILE FLOOR. SIMPLE TO INSTALL BUT HIGHER RUNNING COSTS THAN WET UFH.

3. INFRARED CEILING PANELS: INFINITY INFRARED OR HERSCHEL INFRARED GLASS CEILING PANELS — SUITABLE FOR HIGH-CEILING ORANGERIES WHERE RADIANT HEATING IS PREFERRED OVER CONVECTIVE HEATING. CLEAN, MINIMAL APPEARANCE.

VENTILATION: ANORANGERY WITH SIGNIFICANT GLAZED AREA RISKS OVERHEATING IN SUMMER EVEN WITH SOLAR CONTROL GLASS. VENTILATION OPTIONS: — KORNICHE LANTERN ROOF: OPTIONAL ELECTRIC OPENING VENT PANELS IN THE LANTERN — REMOTE CONTROLLED WITH RAIN SENSOR (CLOSES AUTOMATICALLY IN RAIN) — VELUX INTEGRA ELECTRIC ROOFLIGHT WITH INTEGRAL RAIN SENSOR: FOR FLAT-ROOF-SECTION ADDITIONAL VENTILATION — BIFOLD DOORS: THE PRIMARY SUMMER VENTILATION STRATEGY — FULLY OPENING THE REAR ELEVATION CREATES EXCELLENT CROSS-VENTILATION

THERMAL MASS: HARD FLOORING (PORCELAIN, NATURAL STONE, OR POLISHED CONCRETE) IS RECOMMENDED FOR ORANGERIES — THERMAL MASS ABSORBS SOLAR GAIN DURING THE DAY AND RE-RADIATES AT NIGHT, SMOOTHING TEMPERATURE SWINGS IN A GLAZED SPACE.

ORANGERY COSTS IN LONDON (2025) VARY SIGNIFICANTLY BASED ON SIZE, SPECIFICATION, AND LANTERN COMPLEXITY.

SIZE GUIDE: — SMALL ORANGERY (12-16M2, STANDARD LANTERN): BUILD COST: £55,000-£90,000 (INCLUDING BRICK WALLS, FLAT ROOF + LANTERN, BIFOLD DOORS, UFH, ELECTRICS, PLASTERING, DECORATION) — MEDIUM ORANGERY (18-25M2, PREMIUM LANTERN): BUILD COST: £80,000-£130,000 — LARGE ORANGERY (28-40M2, BESPOKE GLAZING, POLISHED CONCRETE FLOOR, FEATURE KITCHEN ISLAND): BUILD COST: £130,000-£220,000

PRE-CONSTRUCTION COSTS (ADDITIONAL): — ARCHITECTURAL DRAWINGS + BUILDING REGS: £3,000-£6,000 — PLANNING APPLICATION (IF REQUIRED): £258 + CONSULTANT £500-£800 — STRUCTURAL ENGINEER: £600-£1,200 — BUILDING CONTROL: £500-£900 TOTAL PRE-CONSTRUCTION: £4,358-£8,900

LANTERN ROOF COST (SUPPLY ONLY): — STANDARD ULTRAFRAME SYSTEM (3X2M): £2,500-£4,500 — KORNICHE PREMIUM LANTERN (3X2M, TRIPLE GLAZED): £3,500-£6,000 — BESPOKE ARCHITECTURAL GLAZING (CANTIFIX, T-Q3): £8,000-£20,000

CHOOSING A CONTRACTOR: AN ORANGERY IS A PREMIUM PRODUCT — SPECIFY A PRINCIPAL CONTRACTOR WITH EXPERIENCE IN GLAZED EXTENSIONS AND DIRECT ENGAGEMENT WITH A GLAZING COMPANY FOR THE LANTERN AND BIFOLD SYSTEMS. NOVICE BUILDERS WHO TREAT THE LANTERN AS A SIMPLE ROOFER JOB FREQUENTLY CAUSE LEAKS AT UPSTANDS AND GUTTER JUNCTIONS — THE MOST COMMON ORANGERY DEFECT.