Basement
conversions
in Putney, SW15
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Putney's basements range from Stratford Grove villas built with them to Edwardian houses built without, and Wandsworth's LP6 sets the limits on going further.
Putney stretches from the river up towards the heath, within the London Borough of Wandsworth, and its best streets carry conservation protection that the borough backs with Article 4 controls. A basement on Putney Hill — home to grand Victorian villas and mansion blocks — is treated first and foremost as controlled structural work, assessed against that position before excavation method is settled.
The engineering follows the ground rather than the postcode. Costs on a Putney basement depend on whether the house is a villa or a terrace, on party-wall agreements with the neighbours either side, on drainage and rear levels, and on the tree and boundary constraints common along the established streets running down to the river. Putney Hill's villas differ from the Edwardian terraces off Disraeli Road and the Lower Richmond Road in exactly the ways that decide whether a scheme converts an existing cellar or digs a new one.
Those two routes carry very different price tags. Converting cellar space that already exists is measured by the converted area; a fresh excavation with underpinning by the excavated area, with full fit-out counted separately again. We test a Putney Hill or riverside scheme against both routes before recommending either.
Villas with basements, riverside gardens and LP6
Some of Putney's oldest houses were built with space below ground: the appraisal records early Victorian villas of two storeys in Stratford Grove, in brick and render, some with basements, while much of the Edwardian suburb to the west was built as two storeys, often with attic rooms rather than cellars.
By the river, Deodar Road's houses were built just after 1896 as large three-storey houses with long back gardens running down to the Thames, so work below them is also a flood question; we check the address on the government's flood map for planning before design.
Around Putney Lower Common, the appraisal values a largely unspoilt group of high quality buildings facing a semi-natural landscape, built in the mid to late Victorian period, so excavation there is weighed against that setting.
One storey below ground is the limit Wandsworth's Local Plan sets, and beneath a house the basement may take up at most half of the garden behind or around it; a conservation-area lightwell has to leave the larger of two metres or half the original front garden depth untouched.
Rooms below ground that people will live in need daylight and natural ventilation under LP6, and the waterproofing is designed to the British Standard it names, BS 8102:2009.
Outside Putney: Fitzjohns Avenue, NW3, a basement dug beneath a house on Fitzjohn's Avenue, NW3, together with its extension.
We also check the drainage run from the house to the sewer at survey, since a basement below it decides whether the new rooms can drain by gravity or need pumping.
We dig trial pits at the front and back before design, because the depth of the footings and of the water table decide how far a Putney basement can go.
Sources: Wandsworth: Charlwood Road and Lifford Street conservation area appraisal and management strategy; Wandsworth: West Putney conservation area appraisal and management strategy; Wandsworth: Deodar Road conservation area appraisal and management strategy; Wandsworth: Putney Lower Common conservation area appraisal and management strategy; Wandsworth Local Plan 2023–2038 (adopted 19 July 2023).
Basement Conversions in Putney: Questions
Does a Putney basement need a pump?
Where it has a toilet, bathroom or utility room, yes: Wandsworth's LP6 asks for a positive pumped device, or an equivalent, against sewer flooding, and its position goes on the application drawings.
Can a Putney basement extend under the front garden?
Only within limits. LP6 requires a conservation-area lightwell to keep at least two metres or half the original front garden depth, and Oxford Road's appraisal values the front gardens that give its dense streets a very green appearance.
Is basement work in Putney controlled by conservation rules?
Often. Putney has several conservation areas, from West Putney's six character areas to Deodar Road by the river, and their appraisals treat gardens and rear views with care; Wandsworth's LP6 applies on top.
What structural and party-wall work does a basement on Putney Hill involve?
Underpinning the party walls and the house's own walls, with notices to the neighbours: GOV.UK says you must tell your neighbour before digging below and near the level of their foundations.
Which Putney streets suit a basement conversion?
Streets where a basement already exists, such as some of the early Victorian villas of Stratford Grove; West Putney's Edwardian houses are mostly two storeys with attic rooms, and Deodar Road's riverside houses raise flood questions.
How much does converting an existing cellar cost in Putney?
Converting an existing cellar avoids most of the excavation, so the price is set after a survey by the area to be lined and waterproofed, the height available and the light and ventilation it needs.
What does a new basement excavation cost in Putney?
A dig is priced from a survey and a structural scheme: excavation, underpinning, waterproofing and drainage first, then the fit-out, all before VAT.
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