At Cahill Bespoke Construction, we specialise in designing and building high-quality home extensions across North and North‑West London and the Home Counties. We bring architectural vision, meticulous project management, and a transparent working style to every project—delivering beautifully constructed homes.
We routinely solve complex challenges, from integrating modern materials and seamless transitions to managing multiple trade teams in a live home environment. Our clients value our professionalism, honesty, and experience—and we pride ourselves on turning ideas into reality while maintaining tight cost control and ensuring sustainability and workmanship excellence.
Our home extension service includes consultation, design, planning and full construction. Whether you’re adding a single- or double‑storey rear extension, side‑return, wrap‑around, or bespoke glazed space, we handle all steps: architectural briefs, planning/permitted development advice, building regs, foundations, structural work, finishes, and snagging.
We are fully accredited—Gas Safe, Federation of Master Builders, Chartered Institute of Plumbing & Heating Engineers, and SafeContractor—so clients can be confident in adhering to all compliance and safety standards. From initial phone call through to final handover and review, we communicate at every stage to ensure clarity, quality, and an exceptional client experience.
Whether your property sits in affluent areas of North London or the Home Counties, space is at a premium, and extending is often the smarter choice over moving. In London, with tight footprints and dense neighbourhoods, a carefully crafted extension adds both function and value to your home, and can enhance resale value by up to 15–20 %.
Typical timeline in London from initial design through to completion is around four to six months, depending on size, complexity, and whether planning approval is needed. We guide you through permitted‑development rights and full planning applications alike, working to minimise delays while avoiding pitfalls such as missed CIL or planning details.
Typical costs range from £1,300–£2,500 per m² depending on size, finishes, and complexity. A high-end specification might cost £2,500 + per m². VAT and internal fit‑outs (kitchens, bathrooms) are additional to shell costs.
Many single‑storey rear extensions fall under permitted development (up to 6 m for terraced/semi in London) and don’t require planning permission. More complex or larger schemes—including double‑storey or in conservation zones—will need full planning approval, typically within eight weeks.
From planning through to completion, expect about four to six months. Planning or permitted development stage may take 2–3 months, construction usually 3–6 months depending on size and finishes.
In most cases, clients remain in their homes with a safe and managed build environment. For major structural work or where family disruption could be high, we’ll advise on suitable arrangements to minimise inconvenience, setting up temporary kitchens or sealed zones where needed.