House Extension Architects in Putney: Costs, Planning & How to Choose

Written by the Extension Architecture team — ARB-registered architects and chartered town planners working in Putney for almost two decades, with around 60 applications currently managed under Wandsworth Council. Last updated: July 2026.

Putney is classic “improve, don’t move” territory. With the average Victorian home in SW15 valued at well over £1 million, most families weighing up a bigger house against extending the one they have find the maths points firmly at extending. But getting it right starts with choosing house extension architects in Putney who understand both the area’s period housing stock and how Wandsworth Council assesses applications street by street.

Quick Summary: This guide explains how to plan a house extension in Putney and choose the right architect. Putney sits within the London Borough of Wandsworth, where many Victorian and Edwardian homes retain Permitted Development rights — though conservation areas such as Dover House Estate, Putney Embankment and West Putney require full planning applications with closer design scrutiny. You’ll learn which extension types suit Putney’s red-brick family homes, typical build costs (£2,500–£4,000 per sqm), realistic timelines, and how to judge an architect’s genuine Wandsworth track record.

What Makes Putney Homes Ideal for Extending?

Putney’s streets are lined with late-Victorian and Edwardian houses — red-brick exteriors, bay windows, high ceilings and generous gardens. These layouts were built for a different era of living: separate kitchens, narrow side returns and unconverted lofts. That is precisely why they extend so well. A side return infill, rear extension or loft conversion can add 20–40 square metres of living space without losing the period character that makes SW15 so desirable.

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The planning picture is favourable too. Outside conservation areas, many Putney homes retain Permitted Development rights, and terraced or semi-detached houses can often extend up to 6 metres to the rear through the prior approval route. Inside conservation areas — Dover House Estate, Putney Embankment, West Putney and others — Article 4 Directions and design policies mean a full application to Wandsworth Council with careful attention to brickwork, rooflines and window detailing.

Which Extension Types Work Best in Putney?

• Side return and wraparound extensions — the go-to move for Victorian terraces and semis, turning a dark galley kitchen into a light-filled kitchen-diner opening onto the garden.
• Loft conversions — rear dormers add a double bedroom and en-suite; on conservation streets, designs must stay sympathetic to the roofscape.
• Double-storey rear extensions — well suited to Putney’s larger semi-detached plots, adding space on two floors in one build.
• Basement conversions — below-garden basements are established in Putney, though Wandsworth requires structural, hydrology and construction-management detail.

Not sure whether your street falls in a conservation area, or what your Permitted Development rights allow? Book a free 30-minute consultation and we’ll map your fastest viable route before you commission any drawings.

How Much Does a House Extension Cost in Putney?

For a well-specified build in SW15, expect £2,500 to £4,000 per square metre, with basements and structurally complex double-storey schemes at the upper end and beyond. Professional fees — architecture, planning, structural engineering and party wall — typically add 15–20% to construction costs.

Timelines: a Lawful Development Certificate or householder planning application is normally decided within 8 weeks of validation. Party wall notices, which apply to almost every terraced and semi-detached project in Putney, need serving at least two months before structural work starts.

How Do You Choose the Right Extension Architect in Putney?

1. Verify registration. The title “architect” is legally protected — check your practice is registered with the Architects Registration Board.
2. Ask about live Wandsworth experience. Not “have you worked in London?” but “how many applications are you running with Wandsworth Council right now?” Current, repeated contact with case officers is what tells an architect what will be approved on your street — and what will draw objections.
3. Look for planning and design under one roof. Practices with chartered town planners, structural engineers and building regulations specialists in-house avoid the handover gaps that stall projects.
4. Review local work. Ask to see completed Putney and Wandsworth projects, not a generic London portfolio.

Why Homeowners in Putney Choose Extension Architecture

Extension Architecture has worked in Putney for almost two decades and currently manages around 60 applications under Wandsworth Council — a live feedback loop that tells us exactly how the borough’s planners are deciding cases right now. Our in-house team of architects, chartered town planners, structural engineers and project managers has delivered single and double-storey extensions, loft conversions, kitchen extensions and basement conversions across SW15, alongside larger feasibility work such as our Dryers Lane residential scheme. You can see our completed Wandsworth projects or learn more about our planning application service for Putney.

Frequently Asked Questions

Do I need planning permission for an extension in Putney? Not always. Outside conservation areas, many rear extensions and loft conversions fall under Permitted Development. In conservation areas such as Dover House Estate or Putney Embankment, a full planning application is required.

How long does a Putney extension take? Around 8 weeks for a planning decision or Lawful Development Certificate, then typically 3–6 months on site for a single-storey extension.

Will an extension add value to my Putney home? In SW15’s market, well-designed additional space consistently commands a premium — which is why extending is so often the better financial move than upsizing locally.

Start your Putney extension with architects who are in front of Wandsworth’s planners every week. Fixed-fee proposals, in-house planning expertise, full project management. Get your free quote today.