Most Putney kitchen extension projects begin with a Pinterest board and end up rewritten by a wall the owner never thought about. The party wall decides how deep you can go, what your foundations cost, and how long the neighbour conversation takes, which is why architects Putney homeowners work with tend to survey it before sketching anything.
Here's how a typical SW15 project actually unfolds when the sequence is right.
Week One: What the Survey Finds in a Putney Terrace
Putney's housing stock is dominated by Victorian and Edwardian terraces, mostly between 4.5 and 6 metres wide, with a two storey back addition and a narrow side return alongside it.
The survey is looking at four things. Party wall construction, because half brick walls are common in this period and they change your structural approach. Existing foundation depth, which is usually shallow by modern standards. Drainage runs, particularly whether a shared soil stack sits in the way. And the neighbour's own return, because if they've already extended, your options shift.
None of this is exciting. All of it determines cost.
The most common surprise is foundation depth. A Victorian terrace often sits on foundations 400 to 600 millimetres deep. Building next to that means either underpinning or a design that avoids loading it, and the difference between those two approaches is thousands of pounds.
Weeks Two and Three: Designing the Extension Around Real Constraints
Once the survey is in, the design has actual boundaries to work within.
For a full width rear extension, GPDO 2015 Class A caps depth at 3 metres for an attached house where permitted development rights survive. The Larger Home Extension Scheme allows 6 metres through prior approval, which involves a neighbour consultation period and adds time to the programme.
For a side return infill, you're working with a strip typically 1.5 to 2.5 metres wide. That converts a galley into a room you can put a table in, without touching the garden.
The wraparound combines both and is the most common outcome in Putney, because most owners want width and depth. It's also where the structural work gets more involved, since you're removing the rear wall and the return wall in one go.
Rear glazing is where budgets move fastest. Sliding doors, bifolds and roof lanterns all deliver light, but the structural opening above them is what costs money. A steel beam spanning 5 metres carrying floors above is a different order of cost to one spanning 3 metres.
The kitchen extension layout matters less at this stage than people expect. Get the shell and the structure right and the internal arrangement follows. Do it the other way round and the layout gets redrawn when the beam sizing comes back.
Week Four: The Planning Route Decision
Two routes exist and the choice isn't always obvious.
Permitted development is faster where it applies. No design assessment, no officer opinion, and a lawful development certificate available afterwards to confirm the position for future buyers.
Full householder application is required where rights have been removed, where the scheme exceeds the limits, or where the property sits in a conservation area. Putney has several designated areas, including around the Lower Richmond Road and the older streets near the river, so this needs checking on the specific address rather than assumed for the area.
Wandsworth Council handles applications here, targeting eight weeks from validation. Conservation area consultation can stretch that.
The check that saves the most money is planning history. Pull the address through the council portal and see what's already been approved or refused on the building, because previous decisions shape how an officer reads a new one.
Weeks Five to Twelve: Party Wall and Building Regulations
This runs in parallel with the planning decision rather than after it, which is where most programmes lose time unnecessarily.
Cutting into a shared wall to support new structure triggers notice under Section 3 of the Party Wall Act 1996. Excavating near a neighbour's foundation triggers Section 6. Both need serving in writing, with two months notice for Section 3 and one month for Section 6.
Serve early. A neighbour who receives notice with two months of lead time behaves very differently to one who gets it a fortnight before the digger arrives. In a Putney terrace where you'll be sharing scaffolding sightlines and skip space for months, that relationship has practical value.
Building regulations drawings run alongside. Approved Document L governs insulation in the new envelope, which affects wall build up and therefore internal dimensions. Approved Document B covers escape and the fire rating of any new structure. Structural calculations for the beams come with this package.
What a Putney Kitchen Extension Actually Costs
Construction sits at roughly £2,100 to £3,000 per square metre across this part of south west London, with the upper end reflecting specification rather than difficulty.
A 20 square metre wraparound therefore lands somewhere between £42,000 and £60,000 on build cost alone. Glazing, kitchen fit out, flooring and decoration sit on top and frequently match or exceed the shell cost.
Design fees run 8 to 15 percent of build cost depending on how much of the process is handled for you.
The line item people miss is party wall surveyor fees where a neighbour dissents. Two surveyors, an award to prepare, and the cost falls on the party doing the work. Budget for it as a possibility rather than being surprised by it.
Where the Value Actually Lands
The Putney projects that return best aren't the largest ones. They're the ones where the connection between kitchen and garden works properly, and where the new space has genuine daylight rather than a rooflight compensating for a room that's too deep.
A 4 metre deep extension across a 5 metre wide terrace can produce a dark middle zone if the glazing strategy is weak. A 3 metre extension with a well placed lantern and a clear sightline through to the garden often feels bigger.
Buyers in SW15 look hard at that connection, and at how much garden survived. Both are worth protecting when the temptation is to build to the maximum permitted depth.
Kitchen extension projects in Putney typically run six to eight months from first design meeting through to completion.
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