Cost Per Square Foot for a Luxury New Build in Buckinghamshire — 2026

Build cost is the question every serious client asks first. The honest answer is that 'luxury' covers a wide band — and the difference between £350 and £750 per square foot is rarely about square footage and almost always about specification, glazing, services strategy and site complexity.

As a 2026 benchmark, we are currently tendering and contracting work in three broad bands. A refined extension to an existing family home — single-storey, generous glazing, premium kitchen and underfloor heating — sits between £3,200 and £4,200 per square metre (roughly £300–£390 per square foot).

A substantial extension or whole-house remodel, with structural alterations, MVHR, smart lighting, bespoke joinery and stone or engineered timber floors throughout, typically lands between £4,200 and £5,800 per square metre (£390–£540 per square foot).

True luxury new builds and heritage-grade restorations — Passivhaus-influenced fabric, GSHP, pool, cinema room, full home automation, listed brick repair, fine joinery, stone facade work — sit between £5,800 and £8,500 per square metre (£540–£790 per square foot), and exceptionally above.

Two costs are routinely under-budgeted by clients. The first is professional fees: architect, structural engineer, M&E consultant, party wall, planning consultant and building control will typically total 11–14% of construction cost on a project above £750k. The second is external works — pools, driveways, landscaping and garaging — which can comfortably equal 20% of the main contract on a country property.

We provide a fixed-price opinion of cost at feasibility stage, before any drawings are committed to planning. It is the single most useful document a homeowner can have at the start of a serious commission.