💡 Don't move, Improve (AL it)
Find out what your extension is really worth
Two Lawful Development Certificates granted by the London Borough of Sutton.
From an 8m² Kitchen to a 22.8m² Family Hub: a Worcester Park Bungalow Reworked From Top to Bottom
Certified lawful by the London Borough of Sutton — twice. No planning application, no committee, no objections. Don't move. Improve (AL it).
Project facts bar
- Location: Worcester Park, Sutton, South London (KT4)
- Project type: Single-storey side & rear extensions · garage conversion · loft conversion with rear dormer · raised decking
- Services provided: Measured survey · architectural design (Revit/BIM) · two Lawful Development Certificate applications as agent · 3D visualisation [CONFIRM: add structural design & building regulations drawings only if delivered on this project]
- Council & outcome: London Borough of Sutton — two Lawful Development Certificates granted (DM2026/00235 and DM2026/00236)
- The transformation: Kitchen 8.33m² → open kitchen/living/dining 22.82m² · garage 18.18m² → office, utility & shower room · new 13.3m² loft master bedroom with bathroom · roof height unchanged at 6.42m
- Timeline: Ground floor validated 25 February 2026 → certified 5 May 2026 (10 weeks) · loft validated 23 March 2026 → certified 7 May 2026 (7 weeks)
- Estimated value added:
The story
The situation
A traditional bungalow on a quiet Worcester Park road, and a family who had run out of room rather than out of love for the street. The kitchen was 8.33m² a galley doing the work of cooking, homework and family life. The garage held boxes rather than a car: 18.18m² of the footprint earning nothing. Four rooms sat around a dark central lobby with no through-flow, and there was nowhere quiet to work. Moving would have meant stamp duty, agent fees and legal costs before they gained a single square metre.
don't move, improve.
The challenge
The family wanted a lot: more living space, a proper office, and an extra bedroom. Asked for as one planning application, that scope invites scrutiny consultation, neighbour comment, and an officer's judgement that can go either way. The alternative was to design every element strictly inside permitted development, the work a homeowner can carry out without full planning permission, and then ask the council to confirm it in writing. That leaves no room for approximation. Dormer volume, extension depth and the rule that side windows must be obscure-glazed and non-opening below 1.7m all had to be right from the first sketch, not fixed later. The loft added a second constraint: gaining a full bedroom without touching the roof height that gives the street its character.
The solution & result
We split the scope across two Lawful Development Certificate applications so each could be tested cleanly against its own part of the rules. On the ground floor, a side and rear extension dissolved the old lobby and opened the back of the house into a 22.82m² kitchen, living and dining space with doors onto a new raised deck, screened with obscured glass for the neighbours' privacy. The garage became a home office, a utility room and a shower room.18m² brought inside the habitable envelope. In the roof, a flat-roof rear dormer created a 13.3m² master bedroom with its own bathroom and a Juliet balcony to the garden, while the front elevation gained only two low-profile rooflights. The total roof height stayed exactly where it was, at 6.42m.
Sutton granted the ground-floor certificate on 5 May 2026 and the loft certificate on 7 May 2026. The family now has a five-bedroom home with a dedicated office on the same plot, and legal confirmation in writing that none of it needed planning permission.
THE PLANNING ROUTE, IN PLAIN ENGLISH
A Lawful Development Certificate (LDC) is a legal document from the council confirming that your project falls within Permitted Development rights. The extension allowances every eligible house already has under national rules. It is not planning permission, and that's the point: there's no design-taste judgement, no consultation round, just a technical test against fixed criteria.
Getting two LDCs granted meant designing to those criteria precisely, dormer volume limits, extension depths, and details like side windows that must be obscure-glazed and non-opening below 1.7 m.
That's millimetre work, and it's exactly what our in-house drawing and planning team does every week.
- First Certificate: granted 5 May 2026: side & rear extensions, garage conversion, raised decking, fenestration alterations
- Second Certificate: granted 7 May 2026: loft conversion, rear dormer, rooflights
Why we chose certificates over a planning application
The evidence
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