Every loft type across every Westminster roof line — dormer, mansard, hip-to-gable, L-shape, Velux. LDC or full planning route, building regulations, structural calculations and party wall notices, all fixed price.
Every loft type across every Westminster roof line — dormer, mansard, hip-to-gable, L-shape, Velux. LDC or full planning route, building regulations, structural calculations and party wall notices, all fixed price.
Housing stock in Westminster: Grand Georgian and Regency terraces in Belgravia and Pimlico; Victorian and Edwardian mansion blocks; heritage-rich townhouses throughout; very high listed building density.
Character: Heritage-first planning approach; listed buildings on almost every street; basement and rear extension policies particularly strict.
Article 4: Multiple Article 4 Directions — office-to-residential restrictions, HMO conversions, retail to residential in shopping zones.
Basement policy: Westminster basement policy restricts to single-storey, typically under 50% of rear garden footprint; lightwells and rooflights strictly controlled in conservation areas.
We confirm before quoting whether your Westminster loft has the head height and structural capacity.
Most Westminster loft conversions qualify for a Lawful Development Certificate. We check Article 4 and conservation constraints first.
Option studies including massing, internal layout and roof geometry.
Staircase Part K compliance, Part B fire escape, Part L insulation, Part E acoustic separation.
Ridge beam, purlins, steelwork, floor joist upgrade, dormer framing — chartered engineer sign-off.
Almost every Westminster loft triggers Party Wall notices. We draft notices and coordinate with surveyors.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Direct answers to the questions Westminster homeowners ask every week about loft conversion drawings.
Start a free quote →It depends on your exact address in Westminster. Most standard loft conversions qualify as Permitted Development (no planning permission needed) if under 40m³ for terraced or 50m³ for semi-detached, with matching materials and 20cm eaves setback. However Westminster has Article 4 Directions that may remove these rights — and flats, conservation areas and listed buildings always require full planning. We confirm permitted development eligibility at the free feasibility visit.
Our architectural technology fees for a Westminster loft conversion start at £1,225 (planning + building regs + structural). Typical construction build-cost in Westminster is £45,000–£80,000 for a standard dormer and £65,000–£110,000 for a mansard.
Mansards in Westminster are more heavily scrutinised than in outer boroughs. Westminster City Council prioritises heritage and townscape — approvals require exceptional design quality, clear precedents on the street, and a full Heritage Statement. We've delivered mansard approvals in the borough; each application is bespoke.
2.3m measured from existing ceiling joist to existing ridge is the practical minimum for a standard conversion in Westminster. Below 2.2m usually requires dropping the ceiling below (reducing rooms on the floor beneath) or redesigning as a mansard.
Most Westminster loft conversions trigger Party Wall Act notices — legal notices to all adjoining owners. Rear dormers can also prompt right-to-light considerations in dense terraced streets, particularly in Mayfair. We handle both processes.
We cover every London borough with the same fixed-fee approach. If your property sits on a boundary, here are the neighbouring options.
We cover every architectural technology service in Westminster with one chartered team.
From £840. A fixed-fee, end-to-end service — measured survey, scaled drawings, Design & Access Statement where required, Planning P...
From £840. A construction-ready drawing package compliant with every Approved Document — Part A structure, Part B fire, Part L ther...
From £1,225. The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with ...
From £1,575. {location}'s most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards t...
From £995. Turn your unused {location} garage into a bedroom, home office or open-plan kitchen-diner. Planning route assessment, fu...
From £1,950. Full architectural technology service for basement digs and cellar conversions in {location} — structural underpinning d...
From £350. Chartered structural engineer calculations for every residential intervention in {location} — steel beams, lintels, pad ...
From £450. End-to-end Party Wall Act 1996 service for {location} — Section 1, 3 and 6 notices, schedule of condition surveys, party...
From £1,225. London's most popular loft type — the full-width rear dormer. Planning or Permitted Development route assessed for your ...
Free quote in 60 seconds. Fixed fee from £1,225. MCIAT chartered.
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