How do I build an outdoor kitchen plinth?

Build a three-sided block plinth on a concrete foundation (C25, 150mm deep). Use 100mm dense concrete blocks or engineering bricks, laid to courses with 10mm mortar joints. The standard worktop height is 900mm (approximately 4 courses of blocks on a slab). The plinth must be level with falls for drainage. Leave openings for service connections.

What worktop material is best for outdoor kitchens?

Granite and porcelain slabs are the most popular choices for UK outdoor kitchens — both are frost-proof, heat-resistant and low-maintenance. Granite costs £200-400/m². Porcelain large-format slabs (£150-300/m²) are lighter and can be bonded directly to the plinth. Avoid marble (stains easily) and timber (maintenance-heavy) in the UK climate.

Do I need planning permission for an outdoor kitchen?

Most garden outdoor kitchens fall under permitted development if they are single-storey, not in front of the principal elevation, and the total area of outbuildings doesn't exceed 50% of the garden. However, gas and electrical installations must comply with Building Regulations and should be done by qualified Gas Safe and Part P registered tradespeople.

What drainage does an outdoor kitchen need?

You need a drainage fall of 1:80 minimum away from the kitchen structure. A sink requires a waste pipe connected to the foul drainage system (not surface water). The paving around the kitchen should have a 1.5-2% fall away from the house. Install a trapped gully for any wash-down areas.

Can I have gas and electric in an outdoor kitchen?

Yes, but both must be installed by qualified professionals. Gas must be installed by a Gas Safe registered engineer with outdoor-rated fittings and an isolation valve. Electrical supply must comply with BS 7671 (Part P) with RCD protection, weatherproof sockets and an isolator switch. Budget £500-1,500 for gas and £300-800 for electrical installation.

TradeCalculator

Outdoor Kitchen Calculator — Block Plinth, Worktop & Services

Calculate blocks, worktop area, foundation concrete and service routing for an outdoor kitchen plinth.

Total Kitchen Length

L-shape = sum of both sides

Plinth Height

0.9m standard worktop height

Plinth Depth

Front to back dimension

Worktop Material

Worktop Price

Block Price

How We Calculate This

This calculator determines the block count, worktop area, foundation concrete and service requirements for an outdoor kitchen plinth.

Block plinth

Courses = ceil(Height / (Block Height + Joint))
Blocks = Blocks per Course x 3 Sides x Courses x (1 + Wastage%)
Three-sided plinth using 440 x 215 x 100mm dense concrete blocks.

Worktop

Worktop Area = Total Length x Plinth Depth
Allow 25-50mm overhang each side. Foundation at 150mm depth over compacted sub-base.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.