A rear extension in Greenwich begins with the existing rear building line and how far the generous gardens behind the Victorian and Italianate villas around Maze Hill and Westcombe Park will actually allow it to project. A deep plot invites an ambitious footprint, but the decisive question is not how much garden exists — it is how far the addition can extend before it erodes usable amenity space, overshadows an adjoining garden or reads as an over-development of the plot. We test single-storey depths in section against the daylight reaching neighbouring windows, the height and position of boundary walls and any mature trees the borough will want retained, and from that we set a projection that is both genuinely liveable and defensible when the Royal Borough of Greenwich comes to assess it. Fixing the building line on evidence rather than optimism is what keeps the rest of the design stable.
The choice between one and two storeys changes the assessment entirely. Single-storey rear extensions are the most common here and turn largely on garden impact and the daylight reaching a neighbour. A two-storey rear addition — realistic on some of the larger detached and semi-detached villas with depth to spare — brings first-floor windows, outlook and a sense of enclosure over a neighbour's garden into play, and it is far more sensitive where two houses share a party boundary and a projecting upper floor would sit hard against the attached home. We advise early which storey height a given house and plot can carry, because committing a two-storey design to a planning submission the plot cannot actually support tends to cost months rather than deliver the extra space, and a redesign back to a single storey rarely recovers the lost time.
What makes Greenwich distinct is that even an entirely unlisted house is judged against its wider setting. Central Greenwich lies within, or immediately alongside, the Maritime Greenwich World Heritage Site — which encompasses the Old Royal Naval College, the Queen's House and the Royal Observatory — and alterations are assessed for their contribution to that setting and to the several conservation areas that cover much of the town. For a rear extension this means the roof form, the height and the way the addition might read in the wider view toward Greenwich Park and the river are scrutinised rather than assumed acceptable, and permitted development rights are frequently restricted so the fallback of building without an application is often unavailable. Where the property is itself listed, listed building consent is required in addition to planning permission, so we confirm the designation for the exact address before any design is committed.
Roof form and materials are where a rear extension is won or lost aesthetically. A flat roof with a discreet parapet, a shallow mono-pitch or a glazed lantern each suit different host buildings, and the right choice depends on the eaves height, the pattern and rhythm of the existing rear elevation and how the addition is seen from the garden and any longer view toward the park. Where a host villa is finished in stucco or render, or built in London stock brick, we weigh whether painted render, brick or a deliberately restrained contemporary material sits best against it, and we detail the junction between the new work and the original wall carefully so the extension reads as clearly subordinate. The aim throughout is an addition that serves the villa rather than one that competes with it for attention.
Daylight deserves early attention because Greenwich villas, though generously spaced, still sit close enough for a rear extension to affect a neighbour. The Royal Borough assesses daylight and sunlight to neighbouring windows using the established BRE tests, and a well-judged section — controlling the height near the boundary and stepping the roof down toward it — usually keeps a scheme within them. Right to light is a separate civil matter that a planning consent does not resolve, so where an extension approaches a neighbour's window we flag it early rather than let it surface late. Where foundations are excavated within three or six metres of a neighbour's structure, or built on the line of junction, the Party Wall etc. Act 1996 runs alongside the planning process, and on the terraced and semi-detached houses of the borough's slopes those notices commonly go to the neighbours on either side.
From there the route is a coordinated one. We survey the house, test the extension against the planning, heritage-setting and daylight constraints, and develop a design a Greenwich case officer can realistically support, then produce the planning drawings and, once the principle is settled, the building regulations package that covers structure, drainage, insulation and the rest of the technical detail for construction. On the closely built villa and terrace plots typical of the borough's slopes the Party Wall etc. Act 1996 usually applies, so we identify the notifiable neighbours and coordinate with a party wall surveyor in parallel rather than in series. Throughout, we keep the client informed of where the scheme stands against each constraint, so decisions on depth, storey height and materials are made with the trade-offs visible. The result is a rear extension that adds real, usable family space without unbalancing the villa or eroding the garden setting the area is valued for.
