Building work in Balham: area guide

This is our area guide to building work in Balham (SW12, Wandsworth): the housing, the council rules that apply (Wandsworth Council for planning) and every service we offer here. For whole-house refurbishment go to Home renovation in Balham.

A great many Balham addresses are not whole houses. The Victorian terraces around Hildreth Street Market and the streets running towards Tooting Bec Common were divided into upper and lower maisonettes and garden flats decades ago, and that single fact decides which job you are actually asking for. Consent, sound, drainage and shared structure all come into play before a wall is touched. GS Renovation works throughout SW12 on flats, maisonettes and houses, appointing the structural engineer, building to the issued design and coordinating Wandsworth Council building control.

Balham's housing, as the Council Tax list records it, is about 7,240 homes: 45% houses, 55% flats, with 68% pre-1919, 8% interwar and 24% built since 1945. VOA Council Tax stock of properties, March 2025, for Balham and Nightingale Lane. Counts rounded by the VOA.

In a converted SW12 terrace a wall is a freeholder question

In a converted terrace the structure is shared even though the ownership is split. The wall you want out of a lower maisonette often carries the flat above as well as your own ceiling, and the joists spanning your rooms bear into walls your neighbour also relies on. So a load-bearing wall removal here starts with the engineer assessing the whole load path rather than your demise, and with the freeholder's licence to alter obtained before anything begins. Long leaseholders frequently also need the other flat's cooperation for access, settled in writing beforehand.

Sound is the second constant: old conversions rarely had real separation, so timber floors carry footfall and voices straight through. Where a floor is lifted for services we improve it with resilient layers, dense infill between joists and independent ceiling linings rather than nailing boards back down. Moving a bathroom or kitchen in a flat is a drainage question before a design one: waste has to reach the shared soil stack without pipework clipped hard against a party structure, a common complaint between flats. That is a bathroom or kitchen renovation, with the stack route agreed first.

Balham garden flats: find the damp before opening the rear wall

Garden flats in SW12 typically sit part below the external ground level, and that is where the moisture concentrates. A path raised by successive layers of paving, a gully choked with leaves, an air brick rendered over during a past facelift and a rear addition with no cross ventilation under the floor will between them produce the musty smell people assume is rising damp. We find the cause first, because tanking installed over a live external defect only relocates the problem, and we photograph the evidence so you can see it for yourself.

Once the fabric is dry and ventilated, these lower floors make excellent space. Floors are relaid with insulation and a damp proof membrane where levels allow, and opening the rear wall into the garden is an RSJ installation on a designed beam. A bathroom or utility goes only where drainage can reach the existing run. Excavating for headroom is structural alteration work, designed by the engineer and inspected by building control, not something attempted by degrees with a shovel. Party wall notices are served before any excavation near a shared boundary.

Where to go next for work in Balham: house extensions in Balham, the Wandsworth area guide, building work in Streatham, building work in Tooting and How to Choose a Builder.