Designed and Built Properly.
Integrated design-and-build for residential and commercial projects across London and Hertfordshire. One team, one contract, from concept to handover.
- Design & Build Under One Roof
- Residential & Commercial
- Safe Contractor Accredited
- Gas Safe & NICEIC Registered
- Safe Contractor Accredited
- Gas Safe Registered
- NICEIC Approved
- Residential & Commercial
- London & Hertfordshire
- Free No-Obligation Quote
One Team. Every Stage.
KV Design & Build Ltd is an integrated design-and-build contractor covering London and Hertfordshire. We manage residential and commercial projects from initial design through planning, construction, and fit-out — under a single contract with a single team.
That means no gaps between your architect and your builder, no blame-shifting when things need resolving, and no need to manage multiple contractors yourself. You deal with us, and we deliver.
From a rear extension on a North London Victorian terrace to a full hospitality fit-out in central London, from a loft conversion on a Hertfordshire semi to a new-build residential property — we bring the same rigour, the same standards, and the same integrated approach to every project.
What We Build
Residential construction, commercial fit-outs, and everything in between — design-and-build under one roof.
Design & Build
A fully integrated design-and-build service that takes your project from initial concept through planning and construction to handover — one team, one contract, no gaps.
Learn moreBuilding Construction
Full building construction services for residential and commercial clients across London and Hertfordshire, from groundworks through to structural completion.
Learn moreExtensions
Home extensions designed and built to extend your living space without the disruption of moving — rear extensions, side returns, double-storey, and wrap-arounds across London and Hertfordshire.
Learn moreConversions
Loft conversions, basement conversions, and garage conversions that unlock space you already own — designed, built, and finished by one team.
Learn moreRefurbishment
Full-property and room-by-room refurbishments that bring period homes and commercial spaces back to their best — or reimagined entirely.
Learn moreResidential Builds
New-build residential properties and self-build projects across London and Hertfordshire, managed design-to-completion by an integrated team.
Learn more- Design & BuildUnder one roof
- Residential & CommercialFull project range
- Fully InsuredAccredited teams
- London & HertsLocal coverage
Design. Build. Deliver.
Integrated from day one
Design, planning, and construction managed by one team from the first meeting. No handover gaps, no conflicting instructions, no finger-pointing.
Safe Contractor, Gas Safe, NICEIC
Fully accredited across construction, gas, and electrical disciplines. All work meets the required standards — and we can prove it.
Residential and commercial
From family home extensions and loft conversions to restaurant fit-outs and retail shop fitting — we have the depth to handle diverse project types.
Local to London and Hertfordshire
Based in the Welwyn Garden City and Hatfield area, with teams operating across North London boroughs and the wider Hertfordshire commuter belt.
Single point of accountability
One contract, one contact, one team responsible for the outcome. We coordinate every trade on site so you don't have to.
Fully insured
Comprehensive insurance cover on all projects. Combined with our accreditations, you know the work is protected from start to finish.
Recent Projects
A selection of residential and commercial projects across London and Hertfordshire.
Where We Work
Covering London boroughs and the Hertfordshire commuter belt — from Barnet and Camden to Welwyn Garden City, Hatfield, and St Albans.
Accredited & Registered
- Safe ContractorRecognised Safe Contractor accredited contractor
- Gas SafeGas Safe registered
- NICEICNICEIC approved electrical contractor
- Fully Insured
Ready to start your project?
Whether you have detailed plans or just a rough idea, we're happy to talk through what's possible. Contact us for a free no-obligation site visit and quote.