What is included in a build cost per square foot figure?

It depends on the rate. A shell rate covers structure and weathertightness; an all-in construction rate adds fit-out, services and finishes to hand-over. Neither normally includes site infrastructure, external works, professional fees, finance or the land, so always confirm the scope before you use a number.

Is build cost per square foot the same for houses and flats?

No. Apartments generally cost more per square foot than volume houses because of communal areas, cores, lifts and, in taller buildings, extra fire and structural requirements. House type, footprint and storey height all move the rate, which is why each product should be priced separately.

Where can I get a reliable UK build cost figure?

BCIS, the RICS Building Cost Information Service, publishes benchmarked construction and tender price data by building type, region and date. For a specific scheme a quantity surveyor's elemental cost plan is more reliable than any single rate, because it prices your building rather than an average one.

How does build cost affect how much I can pay for land?

Build cost is the largest cost line in a residual land appraisal, and professional fees and finance are often calculated as a percentage of it. An error in the rate therefore moves several lines at once, and the whole change comes off the residual, so a small mistake can move your maximum land bid materially.

Build cost per square foot for UK new-build housing

Threshold Guides · 9 min read · England & Wales

Build cost per square foot is the number that turns a set of house-type drawings into a construction budget, and it sits second only to sales value in any land appraisal. Get it slightly wrong and your residual land value moves by more than the sum you were haggling over with the agent. This guide covers what actually drives the rate, why shell and all-in figures are not interchangeable, where to source a defensible number, and how build cost flows into the maximum you can bid for a site.

Shell cost, all-in cost, and what your rate includes

The first mistake is comparing two rates that measure different things. A shell or superstructure rate covers substructure, frame, external envelope and roof: the building stood up and weathertight. An all-in construction rate adds internal fit-out, mechanical and electrical services, kitchens, bathrooms and finishes: the home ready to hand over. Neither figure typically includes the things developers forget, namely site infrastructure (roads, drainage, utilities), external works (drives, landscaping, boundaries), professional fees, finance or the land itself.

Before you use any per-square-foot figure, pin down three things: what construction scope it covers, what floor-area basis it is measured against (almost always gross internal area), and what date and region it reflects. A 2019 rate for a flat site in the North East tells you very little about a 2026 sloping site in the South East.

What actually drives the rate

House type and footprint. Detached houses, semis and terraces of the same specification cost different amounts per square foot. Terraces and flats share walls and structure, which can pull the rate down; small or complex footprints push it up. Simple rectangular forms are cheaper to build than articulated ones with lots of corners.
Storey height. Going taller changes the structure and, above certain thresholds, the regulations. Apartment blocks generally cost more per square foot than volume houses because of communal areas, cores, lifts and, for taller buildings, additional fire and structural requirements.
Specification. The gap between a volume-builder standard and a high-end private finish is large and lands almost entirely in fit-out and M and E. Higher energy standards (better fabric, heat pumps, ventilation) add cost too, and are increasingly mandatory rather than optional.
Region. Labour and material prices vary across the country, so a single national average will over-state or under-state your scheme depending on where it sits.
Externals and infrastructure. Roads, sewers, attenuation, utilities, retaining and landscaping. On a tight urban plot these can be modest; on a greenfield site with a long access and off-site highway works they can be a large fraction of the build.
Abnormals. The site-specific costs that never appear in a benchmark rate: contamination and remediation, poor ground needing piling, demolition, sloping ground, a high water table, tree constraints, diverting services. Abnormals are where budgets are quietly lost.

Where to source a defensible number

Do not price a scheme from a figure you half-remember. The recognised UK benchmark is BCIS, the Building Cost Information Service run by RICS, which publishes construction cost and tender price data by building type, region and date, rebased to current prices. A quantity surveyor will turn drawings and a specification into an elemental cost plan, which is far more reliable than any single rate because it prices your building rather than an average one. Contractor pricing on comparable recent schemes is a useful third source. Use more than one and reconcile them.

As an order of magnitude only, new-build housing construction is often discussed in the low-to-mid hundreds of pounds per square foot for volume houses, with apartments and high-specification homes sitting higher. Resist the temptation to treat any published mid-point as a fact for your site: the honest answer is a range, sourced to BCIS or a QS and then adjusted for region, storey height and specification.

Gross internal area: the denominator that quietly moves everything

A per-square-foot rate is meaningless without the area it divides into. Construction rates are quoted against gross internal floor area, the space measured to the internal face of external walls, including circulation and internal partitions. Sales evidence often runs on a different basis, and EPC floor areas (which Threshold uses to build its per-square-foot sales evidence, published as live rates by area) follow their own convention. When you multiply a build rate by an area, both must be on the same basis, or you bake in an error of several per cent before you begin. Keep build cost on gross internal area and be explicit about which basis each side of the appraisal uses.

How build cost feeds the residual land appraisal

Build cost is the largest cost line in a residual appraisal, and it drives two of the others. The residual method sets the land price as whatever is left once costs and profit come out of sales value.

Residual land value = GDV - build cost - professional fees - finance - developer profit

Build cost = construction rate (per sqft) x gross internal area, plus externals, infrastructure and abnormals, plus a contingency.

Professional fees are commonly 8-12% of build cost. Development finance typically runs at around 6-8%. Developer profit is usually taken at 15-25% of GDV.

Because fees, and often finance, are calculated as a percentage of build cost, an error in the rate is amplified: it moves the fee line, the finance line and the contingency at the same time, and every pound of that change comes straight off the land value. That is why a serious appraisal prices build cost from a cost plan and then tests it, re-running the residual at a higher build rate to see whether the land bid still stands. Our guides to the residual land value calculation and development viability show how the rest of the appraisal fits together.

Building your own rate, and stress-testing it

Treat the headline rate as a starting hypothesis, not an answer. Build it up: a base construction rate for the house type and region, an uplift for specification and energy standards, a separate site-specific allowance for externals and infrastructure, an explicit abnormals line taken from a site investigation, and a contingency that reflects how much you actually know. Then flex it. If a 10% rise in build cost turns a viable site into a marginal one, the deal was relying on optimism, and the land price, not the contractor, is the thing to renegotiate. You can appraise a site's sales side in under a minute with Threshold; hold the same discipline on the cost side and the two halves of the residual will bear weight.

Frequently asked questions

What is included in a build cost per square foot figure?: It depends on the rate. A shell rate covers structure and weathertightness; an all-in construction rate adds fit-out, services and finishes to hand-over. Neither normally includes site infrastructure, external works, professional fees, finance or the land, so always confirm the scope before you use a number.
Is build cost per square foot the same for houses and flats?: No. Apartments generally cost more per square foot than volume houses because of communal areas, cores, lifts and, in taller buildings, extra fire and structural requirements. House type, footprint and storey height all move the rate, which is why each product should be priced separately.
Where can I get a reliable UK build cost figure?: BCIS, the RICS Building Cost Information Service, publishes benchmarked construction and tender price data by building type, region and date. For a specific scheme a quantity surveyor's elemental cost plan is more reliable than any single rate, because it prices your building rather than an average one.
How does build cost affect how much I can pay for land?: Build cost is the largest cost line in a residual land appraisal, and professional fees and finance are often calculated as a percentage of it. An error in the rate therefore moves several lines at once, and the whole change comes off the residual, so a small mistake can move your maximum land bid materially.

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Data referenced in Threshold is displayed under the Open Government Licence (HM Land Registry Price Paid Data, EPC Register, ONS, UK HPI). All figures produced by Threshold are statistical estimates for site appraisal, not RICS valuations.