Decking Cost Calculator UK (Composite & Timber)
Calculate UK decking project cost by area and material type. Includes boards, frame, fixings, foundations, and labour for typical residential decks.
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UK Decking Cost Guide 2024
What do I need to know about Material Comparison?
Pressure-treated softwood: cheapest. £25-40/m² for boards. Lasts 10-15 years with regular maintenance (annual oiling). Affordable starter material. Splinters, warps over time. Stained colour fades. Hardwood (iroko, cumaru, garapa, ipe): £70-120/m². Lasts 20-30+ years. Beautiful natural finish. Dense, doesn't splinter as readily as softwood. Sustainably-sourced increasingly available (FSC certified). Composite (basic — wood-plastic composite, WPC): £60-100/m². 15-20 year lifespan. Low maintenance, though basic composites can fade or show wear faster than premium capped composite boards.
What do I need to know about Installation Realities?
Sub-frame is half the project. Treated softwood joists at 400mm centres. Posts/Adjustable footings every 1.5-2m. Joist hangers, galvanised brackets. Galvanised or stainless steel fixings (rust visible on cheap fixings within a season). Cost: £20-40/m² for materials alone. Foundations: ground level: gravel base 100mm + permeable membrane. Low decks: concrete pads or screw piles. Raised decks: deeper concrete footings to frost depth (450mm+). Elevated decks: full structural design needed. Labour: typically 40-60% of the total project cost for a straightforward ground-level deck, rising further for elevated or structurally complex designs.
What should I know about Maintenance Requirements?
Pressure-treated softwood: clean annually (jet wash or brush + decking cleaner). Oil/stain every 1-2 years (£20-40 per deck). Replacement boards every 5-10 years for high-traffic spots. Hardwood: oil with hardwood oil every 1-2 years to maintain colour. If left to grey naturally: clean annually only. Either approach works — depends on aesthetic preference. Composite (WPC): annual clean with deck cleaner. No oiling, sealing, or painting needed. May stain from oily food spills. Recyclable, but only through specialist facilities rather than standard kerbside collection, since composite decking is a mixed material that most recycling centres can't process.
What's the key thing to understand about Planning & Compliance?
Planning permission: usually NOT required for ground-level/low decking under 30cm high covering less than 50% of garden. Required if: deck height over 30cm — many councils require planning even at low heights now. Conservation areas: stricter. Listed buildings: virtually always need consent. Building regulations: required if deck height enables a 1.5m+ drop (railings needed, structural sign-off required). Building Regs Part K: 1.1m minimum balustrade height. 100mm maximum gap between spindles. Check with your local planning authority before building anything over 300mm high, since permitted development rights for decking are more restrictive than for many other garden structures.