Two Councils, One Postcode: Choosing Builders in Clapham SW4

What follows is organised the way the work actually divides in Clapham — by job, with the planning position, the cost drivers and the practical constraints kept together rather than scattered across the page.

The side return

The defining Clapham project. The closet-wing plan of a Victorian terrace throws away usable width down one side, and reclaiming it transforms a dark galley kitchen into the room people actually want.

Planning: it sits behind the building line and out of public view, which is why side returns and rear extensions remain the most consistently consented work in the conservation areas. Restrictions bite at the front, not the back.

What drives the cost: structural opening width and the steel to span it, the drainage that almost always runs where you want to build, and the glazing specification, which is where budgets quietly expand.

Watch for: party wall notices on both flanks, and neighbours who have already extended — their foundations affect yours.

The loft

Clapham’s terrace pitches convert well, typically yielding a double bedroom and en suite, occasionally two rooms on the wider Abbeville stock.

Planning: rear dormers are the workable route. Front-facing dormers and rooflights on a visible slope are the applications most likely to be resisted in a designated area, because they interrupt a uniform terrace roofline — precisely what the designation exists to protect.

What drives the cost: ridge height and rafter depth determine whether it works at all, and where the new stair lands determines whether the floor below survives intact. Both are structural questions to answer before anyone sketches a bedroom.

Watch for: flats have no permitted development rights whatsoever, so a top-floor conversion is a full application plus freeholder consent, every time.

The whole house

Our largest Clapham jobs: complete renovation — rewire, replumb, heating, insulation suited to solid-wall construction, layouts reconfigured, kitchen, bathrooms, joinery and finishes as one continuous programme.

Planning: internal work generally needs none, but the moment it combines with an extension or loft the whole scheme travels together, and it should be designed that way from the outset.

What drives the cost: what previous owners left behind. Clapham stock has typically been extended, converted or altered at least once, and undoing poor work is slower than doing new work.

Watch for: phasing costs more than it saves. Opening a house up once is materially cheaper than opening it three times.

The flat

A very large share of Clapham — more than most areas — is converted flats and mansion blocks. This work is a substantial part of what we do here, and most builders’ sites ignore it entirely.

Planning is rarely the binding constraint. Your lease is. It governs wet room positions, floor finishes, anything touching a party wall or shared structure. Freeholder or managing agent consent runs on a separate track from the council, on its own timetable, and securing one does not secure the other.

What drives the cost: access and hours set by the building, waste routes, protection of common parts, and the sequencing that consent conditions impose.

Watch for: starting work on the strength of planning permission alone. It is the most expensive mistake available in a leasehold flat.

The commercial conversion

If you are eyeing a shop, office or former service unit near the High Street with residential conversion in mind, one thing overrides the rest.

In 2021 Lambeth made three Article 4 directions removing the Class MA permitted development right — the route that otherwise lets commercial premises become dwellings without a full application. They cover the borough’s Central Activities Zone, designated industrial and business land, and named town centres. Among those named: the Clapham High Street primary shopping area, and nine further locations in and around Clapham High Street town centre.

That route is shut. It is a full planning application judged on merits, and it is not a formality. We will give you the position before you exchange, not after.