Building work in Forest Hill: area guide

This is our area guide to building work in Forest Hill (SE23, Lewisham): the housing, the council rules that apply (Lewisham Council for planning) and every service we offer here. For whole-house refurbishment go to Home renovation in Forest Hill.

Forest Hill has plenty of terraces and flats, but its larger houses are villas, and villas behave differently once work starts. The detached and semi-detached houses in the streets between the Horniman Gardens and Mayow Park were built with generous halls, tall sash windows, big cut roofs and, crucially, a gap at the side that terraced London does not enjoy. Many were divided into flats decades ago and are now being reassembled, floor by floor, into family houses again. We work across SE23 without keeping premises in the area, coordinate the structural engineers and building control, and route each job by which of those features it touches.

Forest Hill has around 11,040 homes on the Council Tax list: 30% post-war, 13% interwar and 54% predate 1919, with 58% flats and 42% houses. VOA Council Tax stock of properties, March 2025, for Forest Hill West, Forest Hill East and Honor Oak. Counts rounded by the VOA.

Reassembling a divided SE23 villa starts with paperwork

A house split into flats acquires a specific set of scars. Extra kitchens and bathrooms appear in odd corners, the original staircase is boxed in behind a fire door, a hall is chopped into a lobby and services are duplicated three times over. Reversing that starts with paperwork rather than a crowbar: reverting flats into one dwelling can require planning permission from Lewisham Council, and where the freehold and leases are not all in the same hands the legal position has to be resolved first. We check both before quoting.

Physically, the risk sits in what previous conversions did to the structure: openings formed in spine walls with inadequate support, joists notched for waste pipes, and ceiling and floor build-ups altered for the sound and fire requirements that applied to flats. Each such opening is a load-bearing wall removal problem, assessed and redesigned by a structural engineer we appoint, then built to that design. Reinstating the original circulation, taking out redundant risers and replastering to one standard is home renovation work, and it makes a reassembled villa read as one house rather than three stacked apartments.

Side access and big roofs decide how a Forest Hill villa grows

Side access is the quiet advantage of an SE23 villa. Where a route exists round the flank, materials reach the garden without crossing your carpet, spoil goes out the same way and a house extension job at the rear goes ahead without turning the hall into a haul road. It also makes machine excavation possible where a terraced site would be dug by hand. We measure that route at survey, including gate widths and any level changes, because it dictates plant, programme and how disruptive the job feels while you live through it.

The roofs matter even if you never convert them. These houses carry substantial cut roofs with purlins, valleys and multiple stacks, and the purlin struts often land on internal walls below, so a ground or first floor wall you want removed may be carrying part of the roof, which the structural engineer establishes before it becomes an RSJ installation, and Lewisham Council building control inspects at the appropriate stages.

Where to go next for work in Forest Hill: house extensions in Forest Hill, the Lewisham area guide, building work in Dulwich, building work in Catford and Renovation Order of Works.