Builders in Kensington and Chelsea: Conservation Area & Basement Specialists in SW3, SW7, W8 & W11

Very likely, yes. The Royal Borough has 38 conservation areas covering nearly three quarters of its area and around 3,800 listed buildings, so a full planning application is usually required even for modest external works. We check your specific address before any design work starts.

The Royal Borough protects 38 conservation areas, covering nearly three quarters of the borough. Article 4 Directions apply within many of these, controlling small-scale external changes that would otherwise harm the area's historic character.

Only with full planning permission. A borough-wide Article 4 Direction, in force since 28 April 2016, removes all permitted development rights for basement extensions, so there is no permitted development route anywhere in the borough. Local Plan Policy CL7 limits new basements to a single storey and no more than 50 percent of the garden, and requires a full basement impact assessment.

The Thames itself presents little direct flood risk here, but the borough suffered flooding in 2007 along the route of the lost Counters Creek, which once flowed from Kensal Green through North Kensington to the Thames at Sands End. The council has worked with Thames Water since on drainage improvements and anti-flooding devices, and surface water and sewer flooding remain the real risks to plan around.

A single-storey rear extension typically costs £4,000 to £5,500 per square metre or more at a mid specification, among the highest rates of any London borough. Basement space typically runs £6,000 to £8,000 per square metre under a garden, or £8,000 to £12,000 or more under the house itself.

The Royal Borough's average processing time across all applications runs to 8.6 weeks, close to the statutory target, and the council approves a genuinely high share of what it decides, 94.3 percent of householder applications over the year to Q1 2026, one of the highest approval rates in London despite the borough's heritage density.

Almost certainly, in the more terraced parts of the borough. Chelsea, South Kensington and Notting Hill's terraces sit close enough together that a rear extension, loft conversion or basement can fall within 3 metres of a neighbouring property, triggering the Party Wall etc. Act 1996. Notices need serving at least two months before work starts, and we handle this as part of the project.

We cover the whole Royal Borough, including Notting Hill, North Kensington, Holland Park, South Kensington, Earls Court, Chelsea and Brompton, across postcodes SW3, SW5, SW7, SW10, W8, W10 and W11.

Both boroughs protect a huge share of their area through conservation status and hold thousands of listed buildings, but Kensington and Chelsea's householder approval rate of 94.3 percent runs well above Westminster's 81.3 percent. The exact reasons aren't published by either council, but well-prepared, heritage-aware applications matter in both boroughs regardless of the headline approval rate.

In practice, no. Local Plan Policy CL7 and the 2016 Basements SPD limit new basements to a single storey below the lowest original floor, and neighbouring Westminster applies a similarly strict policy. Both boroughs have effectively prohibited new two-level basements as a result.

Notting Hill Carnival closes much of North Kensington to non-resident vehicles for a full bank holiday weekend every August, Europe's largest street festival. Any project in this part of the borough needs deliveries, skip placement and scaffolding work scheduled around the Carnival calendar rather than risk a clash.

The 2007 flooding followed the route of the lost Counters Creek, which once flowed from Kensal Green through North Kensington to the Thames at Sands End in Fulham, and is now a culverted sewer. Heavy rainfall overwhelmed the sewer system along the old creek route, and the council has since worked with Thames Water on sustainable drainage and anti-flooding devices.

Often, yes, but the design needs to respect the conservation area's character, and roof-level changes are one of the most common Article 4-controlled alterations across the borough's 38 conservation areas. We check the specific conservation area guidance for your street before finalising any loft design.