Kingston upon Thames, London
Boroughs · South London
Kingston upon Thames · Outer London

House extensions in Kingston upon Thames

Kingston's family-buyer market pays a premium for well-executed rear dormer loft conversions. Detached and semi stock keeps party wall complexity down.

Typical all-in (inc VAT)
£100k–£155k
Cost vs London base
+2%
Postcodes covered
KT1 · KT2 · KT3 · KT5

Housing stock in Kingston upon Thames

Edwardian and 1930s semis, some Victorian villas in Surbiton and Coombe.

Hip-to-gableMansard loftRear dormer

Planning in Kingston upon Thames

Kingston is one of the more design-conscious outer boroughs. Surbiton and Coombe conservation areas add scrutiny.

Party Wall Act — what to expect

Mostly semi-detached — one party wall neighbour.

Read the Party Wall etc. Act 1996 guide for full detail on notices, timelines and surveyor costs.

Typical costs in Kingston upon Thames

For a mid-spec 25 m² rear dormer loft conversion, all-in (structural design, building control, party wall, VAT and 12% contingency), expect roughly £100,000 to £155,000. A mansard, a hip-to-gable with high-spec en-suite joinery or a conservation-area application will push above the top of this range; a self-built rooflight conversion comes in well under the bottom.

Cost tier
Outer London · +2% vs London average

Our calculator applies a 1.02× multiplier automatically for Kingston upon Thames projects. Get an itemised breakdown in 60 seconds.

Get your Kingston upon Thames estimate

Areas we cover in Kingston upon Thames

KT1KT2KT3KT5KT6KT9

Why homeowners in Kingston upon Thames pick us

  • KYB-verified builders only
  • Local Kingston upon Thames project experience
  • Fixed, itemised written quotes
  • Full insurance & warranty checks
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