Home extensions in Lewisham: what you need to know before you Start
Lewisham's terraced streets are full of homes that work hard but could work harder. A well-designed extension can transform a house that feels tight and awkward into one that is generous, light-filled and genuinely comfortable. But getting there requires navigating planning rules, making good material choices and understanding what the borough's conservation officers are looking for. Here is what you need to know.
Permitted development in Lewisham: what you can build without planning permission
Many single-storey rear extensions in Lewisham can be built under permitted development rights, without a full planning application. Under current permitted development rules, a single-storey rear extension can extend up to three metres beyond the rear wall of a terraced house, or four metres for a detached house, under the standard prior approval process. Larger extensions up to six or eight metres are possible under the neighbour consultation scheme.
The important caveat is that these rights are removed or restricted in some parts of Lewisham. Article 4 directions affect parts of the borough, and conservation areas impose additional constraints. Before you assume permitted development applies to your property, it is worth checking with the council or asking your architect.
Conservation areas in Lewisham: what changes
Lewisham has several designated conservation areas, including Forest Hill, Hither Green and areas around Blackheath. In these areas, permitted development rights for extensions are more restricted and/or often removed, and the choice of materials matters more. Conservation officers will expect new work to be sympathetic to the existing character of the area particualry if it is visible from a public highway.
The good news is that the materials that work best in Lewisham's conservation areas are often the most sustainable ones. Reclaimed brick, lime mortar, natural timber and breathable construction are all consistent with the historic fabric of the borough's Victorian and Edwardian streets. A well-argued case for reclaimed materials, with the right supplier information and visual precedent, is generally well received.
Lewisham Council's approach to sustainability
Lewisham's Local Plan has sustainability requirements that are worth understanding before you design. The council is broadly supportive of sustainable design and energy performance improvements. A sustainability statement that explains the embodied carbon choices, the energy performance measures and the material strategy can strengthen an application, particularly in areas where design quality is scrutinised.
New Makers Bureau includes sustainability thinking in every planning application we prepare. Not as a box-ticking exercise, but as a genuine part of the design argument.
Material choices for Lewisham's housing stock
Lewisham's Victorian and Edwardian terraces were built with solid brick walls, timber floors and roofs, and lime mortar joints. They are breathable buildings, designed to manage moisture by allowing it to move through the fabric. Modern materials that are impermeable, rigid foam insulation, cement render, expanding foam, can trap moisture and cause damage if used inappropriately on these buildings.
New Makers Bureau's preference is for materials that are compatible with the existing fabric: wood fibre or hemp insulation rather than rigid foam, lime mortar rather than cement, reclaimed or locally sourced brick rather than new. These choices are better for the building, better for the carbon account and, in most cases, better looking.
Cost benchmarks for Lewisham extensions
A single-storey rear extension in Lewisham at a sustainable specification typically costs between £2,500 and £3,500 per square metre for the building works, depending on the complexity of the design, the specification of materials and the condition of the existing house. Architect and consultant fees add to this. A sustainable specification, using reclaimed materials and natural insulation, adds 5 to 15 per cent to the build cost compared with a standard specification, but the quality and long-term performance typically justify the difference.
Architects in Lewisham: Sustainable Design for a Changing Borough
