SLSelf Lofts
World's End, London
Areas · Kensington & Chelsea · West London
World's End · SW3 · SW5 · SW7

House extensions in World's End

World's End sits in Kensington & Chelsea, where the streets are dominated by long Victorian terraces with steep pitched roofs well suited to a rear dormer. The build that pays back most reliably here is a full mansard that adds a bedroom and en-suite in place of the whole rear roof slope.

Typical all-in (inc VAT)
£178k–£298k
Build rate per m²
£3300–£5050
On-site programme
12–20 weeks
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What we build in World's End

Most World's End projects we scope fall into three buckets: a side-return or rear infill that fixes a dark galley kitchen, a full-width rear extension that opens the ground floor to the garden, and a rear-plus-loft package that adds a bedroom while the scaffold is already up. Stucco terraces, mansion blocks, Georgian and early-Victorian townhouses — mostly Grade II.

Mansard loft conversionRear dormer loftHip-to-gable conversion

Extension costs in World's End

A mid-spec 25 m² extension in World's End typically lands between £178,000 and £298,000 all-in — that figure includes professional fees, planning and Building Control, party wall, a 12% contingency and VAT at 20%. Ex-VAT build rates run £3300–£5050 per m² depending on glazing, structural spans and kitchen spend.

ProjectSizeWorld's End all-in
Rooflight conversion15–20 m²£98k – £164k
Rear dormer kit20–28 m²£178k – £298k
L-shaped dormer kit28–36 m²£240k – £402k
Hip-to-gable + dormer30–40 m²£267k – £447k

Planning permission in World's End

RBKC is the strictest planning authority in London for extensions. Mansard and dormer policy is tight, Article 4 removes PD in most zones, and heritage officers scrutinise everything.

Before you assume permitted development applies to your street, check whether your street falls inside a conservation area or an Article 4 direction — both are common in Kensington & Chelsea and both remove PD rights for rear and side extensions. Our London planning guide walks through the tests in order.

Party wall and neighbours

Mansard and dormer loft work almost always triggers major Party Wall Awards on both flanks — plan for surveyors on all sides.

Serve notice at least two months before you break ground. Budget £1,200–£2,400 per adjoining owner if they dissent and appoint their own surveyor — see the Party Wall Act guide.

Access, logistics and site set-up

Narrow roads limit lorry size, so materials arrive in smaller loads; a good programme allows for it.

Every quote we issue for World's End prices skip permits, parking suspensions, protection and welfare explicitly in the preliminaries — so the number you sign is the number you pay.

Value added in World's End

Buyers in this area consistently pay a premium for open-plan kitchen-diners with direct garden access.

Typical programme

  1. Weeks 0–4Measured survey, design and structural calcs
  2. Weeks 4–12Planning or lawful development certificate, party wall notices
  3. Weeks 12–16Tender, builder selection and contract signing
  4. Weeks 16–34On site: groundworks, shell, watertight, first and second fix
  5. Week 35Building Control sign-off, snagging and handover

Full detail in the London extension timeline guide.

Why homeowners in World's End use us

  • KYB-verified builders only
  • Live Kensington & Chelsea project experience
  • Itemised fixed-price specifications
  • Insurance, warranty and accreditation checks
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