Kensington · West London
Kensington homes are worth a lot of money, which means getting the architecture right matters more than it does almost anywhere else. A good extension or basement here does not just improve your life - it adds serious value to the property. We design and build these projects properly.
Talk to Us About Your Home
Working in Kensington
The typical Kensington project starts with a Victorian or Edwardian townhouse that needs more space, more light, or both. Basement conversions are common here - many properties already have cellars that can be opened up into proper living areas. Rear extensions into gardens are another staple, especially at lower-ground level where the kitchen usually sits.
Loft conversions work well where the roof structure allows it, adding a bedroom and bathroom without changing the footprint. And full house renovations - stripping everything back and rethinking the layout from scratch - are something we do regularly on the larger Kensington townhouses.
RBKC expects high design quality, and so do the homeowners. The standard of specification in this part of London is as high as it gets. That suits us - we care about the details and we have the construction team to deliver them. As experienced residential architectural designers in London, we know how to work at this level.
Services in Kensington
Our design-and-build approach works particularly well in Kensington, where the gap between design ambition and construction delivery needs to be zero. One team handles architecture, planning, interior design and construction under a single contract. No separate builder to find, no miscommunication between design and build.
We also have experience with listed building consent, which many Kensington properties require. Any alterations to a listed building need separate consent in addition to planning permission, and the application process requires heritage impact assessments and detailed justification for each proposed change.
Planning in Kensington
RBKC is one of the most architecturally scrutinised boroughs in London. Conservation areas cover almost the entire borough, and the planning team takes design quality seriously. If you submit something that feels generic or poorly considered, it will not get through.
But they do approve good design. RBKC responds well to projects that show genuine thought about materials, proportions and how the new work relates to the existing building. They want to see that you have studied the character of the street and designed something that belongs there. Contemporary rear additions that sit clearly as new elements tend to fare better than pastiche.
For basement conversions, RBKC's Policy CL7 limits excavation to a single storey below the existing lowest floor. Applications require a Construction Management Plan, a structural methodology statement and assessments covering hydrology and impact on neighbouring properties. Party wall agreements with adjoining owners are also required before work can begin.
Cost Guide
Construction costs in Kensington typically run between £3,500 and £5,000 per square metre, reflecting the quality of finishes expected, the complexity of period properties and the logistical challenges of working on Kensington's residential streets.
A rear extension on a Kensington townhouse usually costs between £100,000 and £250,000 depending on size and specification. Loft conversions range from £70,000 to £130,000 for a rear mansard. Basement conversions typically start at £200,000 and can reach £500,000 or more for a full excavation with high-end finishes. Whole-house renovations on larger townhouses usually run from £300,000 to £700,000.
Professional fees for architecture, structural engineering and building regulations usually add 10 to 15 percent on top of the construction cost. For broader London pricing, see our house extension cost guide.
Cost Calculator
Tell us the size, location and finish level. Our calculator returns a realistic range for your extension or loft conversion, with a detailed breakdown available.
Property Types
Kensington's properties are among the most valuable in London. The area has substantial Victorian and Edwardian townhouses, white stucco terraces around South Kensington, and the grand detached houses of Holland Park. Many are set over four or five floors with existing lower-ground levels that lend themselves to basement conversion.
The colourful streets of Notting Hill have their own character with smaller Victorian terraces and mews houses. North Kensington has a more varied housing stock including mansion blocks and some post-war developments. Each neighbourhood brings different constraints and opportunities - what works for a large Holland Park house may not suit a Notting Hill terrace.
Nearby Areas
Alongside Kensington, we regularly take on projects in Chelsea, Holland Park, Notting Hill, Earls Court, Shepherd's Bush, Hammersmith and Fulham. Chelsea and Kensington share the same local authority (RBKC), so the planning framework is identical.
Outside West London, we work across all of Greater London and within a 30-mile radius, including Hampstead, Islington, Hackney, Wandsworth, Wimbledon, Richmond, Camden and Surrey.
Common Questions
