What Is Design and Build, and Why It Matters
Design and build is a delivery model in which a single company designs a project, secures planning consent and constructs it, rather than a homeowner appointing an architect and then separately appointing a builder once the design is finished. Sovran's studio brings architecture, interiors and project management under one roof, with a single point of accountability from the first sketch to the final snagging walk, closing the gaps where cost, design intent and build quality are most often lost.
Design and Build vs. Separate Architect and Builder
The Coordination Problem
Appointing an architect and a builder separately means two contracts, two invoices, and two parties each managing their own risk rather than the client's outcome. An architect who does not price the build has little incentive to design within budget. A builder appointed after the drawings are finished has no ownership of the design intent, and will often value-engineer it away the moment a cost saving presents itself.
Why One Contract Reduces Risk
Under a single design and build contract, the team that draws the project is the same team that prices it and builds it, so the design is realistic from the first sketch and the price agreed at contract stage does not shift once construction starts. There is one point of contact, one programme, and one party accountable for the result, rather than two parties each able to point at the other when something goes wrong.
One Team, Three Disciplines
Sovran's design and build model runs across three integrated disciplines, coordinated from a single studio rather than subcontracted between separate businesses.
Architecture, Concept to Planning Consent
Every Sovran project begins with architecture: site assessment, concept design, planning applications and building regulation drawings, led by a team that includes former local authority planning officers.
Construction, Extensions, Lofts, Renovations and Basements
The same studio delivers the build: extensions, loft conversions, full renovations and basement conversions, managed on site by a dedicated lead under a fixed programme and a locked specification.
Interiors, Joinery, FF&E and Design Management
Where a project includes interiors, the same team carries the design through material palettes, bespoke joinery and furniture specification, so the interior is considered from the first architectural drawing rather than layered on at the end.
The same model extends to commercial commissions across hospitality, retail and multi-unit development.
How Much Does a Design and Build Project Cost in London?
Typical Investment by Project Type
Sovran delivers design and build projects from £100,000 to £25,000,000 and beyond, spanning single-room renovations through to full new builds. As a guide:
- House extensions and loft conversions: from £55,000
- Full house renovations: £250,000–£1,000,000+
- Basement conversions: £150,000–£500,000+
- Bespoke new builds and ultra-premium projects: £1,000,000–£25,000,000+
Detailed cost guidance for each project type is set out on the relevant service page: house extensions, loft conversions and basement conversions.
Why Design and Build Can Cost Less Than Separate Contracts
Separate appointments carry hidden costs: abortive design fees when a separately appointed builder cannot build the drawings to budget, duplicated project management, and re-work when design intent is lost in translation between architect and contractor. A single design and build contract removes each of these, not by cutting quality, but by removing the coordination failures that inflate separately-contracted projects.
Why Choose Sovran as Your Design and Build Company
RIBA-Certified Architects, Led by Former Planning Officers
Sovran's architectural team includes RIBA-certified architects and former planning officers who have sat on the other side of the desk, a perspective that shapes every submission the studio makes and underpins its 95% planning success rate.
Fixed-Price Contracts, Single Point of Contact
Every Sovran project is delivered on a fixed-price contract with milestone-based payments, agreed before work begins and managed by a single point of contact throughout, rather than split across separate architect and contractor relationships.
15 Years, 1,000+ Projects Delivered
Founded in 2011, Sovran has delivered more than 1,000 projects across London's most prestigious postcodes, from Chelsea townhouses to Hampstead new builds, with a combined portfolio value exceeding £25 million.
Design and Build Projects Across London
Each of these spans at least two of the three disciplines — architecture, construction and interiors — delivered by the same studio under one contract.
Pinner Residence
Architecture, interiors and construction delivered under one roof — planning, structural works and bespoke joinery coordinated in a single phased programme across 410 sqm.
Surrey Estate
A 7,800 sq ft new-build private estate with swimming pool, tennis court and 0.8 acres of grounds, delivered as a single commission across eighteen months.
Gerrard's Cross Residence
A ground-up five-bedroom home with a below-ground wellness level, taken from demolition consent to handover in twenty months on a design-and-build contract.
Design and Build FAQs
Areas We Cover
Sovran delivers design and build projects across London, with particular depth of experience in Kensington, Chelsea, Hampstead, Fulham, Wimbledon and Wandsworth, alongside projects throughout the Home Counties.
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