Garden Decking for London Victorian Terraces: Hardwood, Composite, Planning, and Costs

DECKING MATERIAL OPTIONS FOR LONDON VICTORIAN TERRACE REAR GARDENS: 1. HARDWOOD TIMBER DECKING: SOLID HARDWOOD DECKING BOARDS (TYPICALLY 145MM × 21MM OR 145MM × 28MM) FROM NATURALLY DURABLE HARDWOOD SPECIES (DURABILITY CLASS 1 OR 2 — WHICH MEANS 25+ YEAR DURABILITY FOR ABOVE-GROUND USE WITHOUT TREATMENT): - GARAPA (BRAZILIAN HARDWOOD — BLONDE TO GOLDEN YELLOW — VERY SIMILAR APPEARANCE TO EUROPEAN OAK AT A LOWER PRICE; DURABILITY CLASS 1). VERY POPULAR FOR LONDON VICTORIAN TERRACE DECKING PROJECTS. - CUMARU (BRAZILIAN TEAK — RICH REDDISH-BROWN TO GOLDEN BROWN; DURABILITY CLASS 1). EXTREMELY HARD AND DURABLE. - MASSARANDUBA / IRONWOOD (DEEP RED-BROWN — DURABILITY CLASS 1; VERY HARD). EXCELLENT FOR HIGH-TRAFFIC AREAS. - OAK (EUROPEAN OAK — GREY WEATHERS TO A SILVER-GREY PATINA — DURABILITY CLASS 2; 15-25 YEARS ABOVE GROUND WITHOUT TREATMENT). THE PERIOD-AUTHENTIC CHOICE FOR LONDON VICTORIAN TERRACE GARDENS — SILVER-GREY WEATHERED OAK COMPLEMENTS LONDON STOCK BRICK AND RENDERS WELL. - ACCOYA (MODIFIED RADIATA PINE — ACETYLATION PROCESS; DURABILITY CLASS 1+; 50 YEAR DURABILITY GUARANTEE ABOVE GROUND; STABLE ENOUGH FOR CONCEALED FIXINGS WITHOUT PRE-DRILLING). - MAINTENANCE: OAK AND ACCOYA REQUIRE NO TREATMENT (SILVER-GREY PATINA IS NATURAL AND ACCEPTABLE); TROPICAL HARDWOODS (GARAPA, CUMARU) CAN BE LEFT TO WEATHER OR OILED (OSMO UV PROTECTION OIL, RONSEAL HARDWOOD OIL) EVERY 1-2 YEARS TO RETAIN COLOUR. - COST: GARAPA, CUMARU, OR MASSARANDUBA (BOARDS — PER M²): £30-60/M² SUPPLY ONLY. OAK OR ACCOYA: £60-100/M² SUPPLY ONLY.

2. COMPOSITE DECKING: COMPOSITE DECKING BOARDS CONSIST OF A BLEND OF WOOD FIBRE (TYPICALLY RECYCLED SAWDUST OR RICE HUSKS) AND RECYCLED PLASTIC (HDPE OR PVC), EXTRUDED TO FORM A BOARD PROFILE THAT MIMICS TIMBER. COMPOSITE DECKING DOES NOT NEED OILING, STAINING, OR SEALING — IT IS RESISTANT TO MOISTURE, INSECT ATTACK, AND UV DEGRADATION. - TYPES: \'HOLLOW CORE\' COMPOSITE (LIGHTER — BOARDS HAVE INTERNAL VOIDS; CANNOT ACCEPT FACE SCREWS — CLIP FIX REQUIRED; LOWER COST); \'SOLID CORE\' COMPOSITE (HEAVIER — BETTER ACOUSTIC AND STRUCTURAL PROPERTIES; ACCEPTS FACE FIXING). - APPEARANCE: STONE-GREY, ANTHRACITE, TEAK, AND WALNUT-EFFECT WOOD GRAIN TEXTURES ARE THE COMMON COLOUR RANGES. FOR LONDON CONTEMPORARY REAR EXTENSION PROJECTS, GREY AND ANTHRACITE COMPOSITE DECKING PAIRS WELL WITH DARK ALUMINIUM SLIDING DOORS AND GREY PORCELAIN PAVING. - COST: £20-50/M² SUPPLY ONLY (BUDGET RANGE); £50-90/M² (MID-RANGE — TREX, MILLBOARD, TIMBERTECH, CEDRAL); £100-200/M² (PREMIUM — MILLBOARD ENHANCED GRAIN WEATHERED OAK FINISH). - IMPORTANT: MILLBOARD (A COMPOSITE WITH A POLYROPLENE CORE — NOT HDPE — AND AN EMBOSSED TIMBER-GRAIN SURFACE) IS THE MOST REALISTIC-LOOKING COMPOSITE DECKING — IT IS DIFFICULT TO DISTINGUISH FROM REAL OAK AT 3M DISTANCE. MILLBOARD DOES NOT SPLINTER AND IS WARM UNDERFOOT.

3. ALUMINIUM DECKING: EXTRUDED ALUMINIUM DECK BOARDS (TYPICALLY 145MM WIDE × 30MM HIGH — RIBBED TOP SURFACE FOR SLIP RESISTANCE; HOLLOW INTERNAL SECTIONS FOR LIGHTNESS). ALUMINIUM DECKING IS THE MOST DURABLE OPTION (50+ YEAR LIFESPAN; FULLY RECYCLABLE; DOES NOT ROT, SPLINTER, WARP, OR REQUIRE TREATMENT) AND IS FIRE-RESISTANT. - COLOURS: POWDER-COATED IN STANDARD RAL COLOURS — GREY, ANTHRACITE, BRONZE, SILVER. - COST: £80-150/M² SUPPLY ONLY. - APPROPRIATE FOR COMMERCIAL OR HIGH-SPECIFICATION RESIDENTIAL PROJECTS. HIGHER COST THAN MOST COMPOSITE OPTIONS.

SUB-FRAME SPECIFICATION (JOISTS AND BEARERS): THE DECKING BOARD SURFACE IS ONLY AS GOOD AS THE SUB-FRAME BELOW. FOR LONDON VICTORIAN TERRACE REAR GARDENS: - JOIST SPECIFICATION: PRESSURE-TREATED C16 OR C24 REGULARISED SOFTWOOD (TANALISED — UC4B IF GROUND CONTACT; UC3B IF ABOVE GROUND). JOIST SIZE: 47MM × 100MM (SPAN UP TO 1.8M); 47MM × 150MM (SPAN UP TO 2.4M). JOIST SPACING: 400MM CENTRES FOR 21MM BOARDS; 450MM CENTRES FOR 28MM BOARDS. - BEARER SPECIFICATION: 100MM × 100MM TANALISED POSTS ON ADJUSTABLE PEDESTALS (FOR LEVEL DECKS ABOVE AN UNEVEN SURFACE) OR CAST-IN CONCRETE FOOTINGS FOR ELEVATED DECKS (HEIGHT >300MM ABOVE GROUND). - FIXINGS: USE STAINLESS STEEL FIXINGS (SCREWS, JOIST HANGERS, BRACKETS) THROUGHOUT — GALVANISED FIXINGS CORRODE IN THE WET/HUMID BELOW-DECK ENVIRONMENT, PARTICULARLY ADJACENT TO TREATED TIMBER (WHERE COPPER COMPOUNDS ACCELERATE CORROSION OF STEEL).

PLANNING RULES FOR DECKING ON LONDON VICTORIAN TERRACES: DECKING IS COVERED UNDER THE SAME PERMITTED DEVELOPMENT RULES AS OUTBUILDINGS (SCHEDULE 2, PART 1, CLASS E — ENGLAND): - GROUND-LEVEL DECKING (UP TO 300MM ABOVE NATURAL GROUND LEVEL): PERMITTED DEVELOPMENT — NO PLANNING PERMISSION REQUIRED. DOES NOT COUNT TOWARD THE 50% CURTILAGE COVERAGE ALLOWANCE WHEN AT OR BELOW NATURAL GROUND LEVEL (INTERPRETATION VARIES — CONFIRM WITH LPA FOR CLARITY). - RAISED DECKING (MORE THAN 300MM ABOVE NATURAL GROUND LEVEL): THE PLATFORM ELEMENT MAY COUNT AS AN OUTBUILDING STRUCTURE AND MUST COMPLY WITH THE CLASS E HEIGHT AND COVERAGE RULES. IN PRACTICE, A RAISED DECK PLATFORM AT 300-600MM ABOVE GROUND IS GENERALLY PERMITTED DEVELOPMENT IF THE AREA OF THE PLATFORM + OTHER OUTBUILDINGS + EXTENSIONS DOES NOT EXCEED 50% OF THE GARDEN. - CONSERVATION AREA: DECKING PERMITTED DEVELOPMENT RULES APPLY IN CONSERVATION AREAS. CONFIRM WITH THE LPA. - LISTED BUILDING: LISTED BUILDING CONSENT IS REQUIRED FOR DECKING WITHIN THE CURTILAGE.

SAFETY AND BUILDING REGULATIONS: DECKING THAT CREATES A DROP OF MORE THAN 600MM (FROM THE DECK SURFACE TO THE GROUND BELOW) REQUIRES A BALUSTRADE (HANDRAIL SYSTEM) COMPLYING WITH BUILDING REGULATIONS PART K: - BALUSTRADE HEIGHT: MINIMUM 1,100MM ABOVE DECK SURFACE. - BALUSTERS: MAXIMUM 100MM SPACING (TO PREVENT A 100MM SPHERE PASSING THROUGH — CHILD SAFETY REQUIREMENT). - BALUSTRADE SPECIFICATION: STAINLESS STEEL POST AND CABLE (CONTEMPORARY); TIMBER POST AND RAIL (TRADITIONAL); GLASS PANEL (FRAMELESS GLASS — MINIMUM 10MM TOUGHENED LAMINATED GLASS FOR BALUSTRADE USE).

COSTS (SUPPLY AND FIT, LONDON 2025-2026): GROUND-LEVEL COMPOSITE DECKING (MID-RANGE COMPOSITE — PER M²): £80-140/M² GROUND-LEVEL HARDWOOD DECKING (GARAPA/CUMARU — PER M²): £90-160/M² GROUND-LEVEL PREMIUM COMPOSITE (MILLBOARD — PER M²): £150-250/M² ELEVATED HARDWOOD DECKING (ADDITIONAL SUB-FRAME COST — PER M²): £120-200/M² TYPICAL LONDON VICTORIAN TERRACE REAR DECK (3M × 4M = 12M² — MID-RANGE COMPOSITE, INCL. SUB-FRAME): £1,200-2,500