Find Trusted Builders in South London

South London has seen substantial building activity over the past decade, driven by rising property values and homeowners choosing to extend rather than move. From rear extensions in Clapham and Tooting to loft conversions in Crystal Palace and Forest Hill, builders across South London are kept busy year-round with both domestic and commercial projects. The borough councils across South London — including Lambeth, Lewisham, Wandsworth, Southwark, and Greenwich — each have their own planning guidelines, and navigating these is often one of the more complex aspects of any building project. Many single-storey rear extensions fall under permitted development rights and do not require planning permission, but it is always worth confirming with your local authority before work begins. What kinds of building work are South London builders known for? Home extensions are the most common project type. A single-storey rear extension to a South London terrace typically costs between £35,000 and £65,000 fully completed, including structural work, glazing, internal finishes, and connections to existing services. Prices vary depending on specification — a basic brick-built extension with a flat roof is cheaper than a contemporary extension with a pitched roof, bi-fold doors, and underfloor heating. Loft conversions are extremely popular across South London. A dormer loft conversion typically costs £35,000 to £55,000 and can add a bedroom and ensuite bathroom, significantly increasing a property's value without the need to move. Most semi-detached and detached properties in South London have sufficient roof space for a loft conversion, though terraces with hip roofs may need a larger conversion to create useful space. Basement conversions are increasingly common in higher-value South London boroughs like Wandsworth and Southwark, though planning requirements are more stringent and costs are substantially higher — typically £80,000 to £200,000 depending on depth and extent. Choosing a South London builder Always check that any builder you hire is a member of the Federation of Master Builders (FMB) or carries a Trust Mark accreditation. These schemes vet members and provide a dispute resolution service. Ask for references from recent similar projects and, where possible, visit a completed job. Get at least three written quotes for any job over £5,000. Quotes should break down labour and materials separately and specify the timeline. Be wary of any builder who asks for more than 25% upfront or who wants cash only.