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.
Westminster's grand Georgian and Regency terraces in Belgravia and Pimlico stock lends itself to rear dormers (most common), hip-to-gable (semi-detached), and mansard (period terraces and conservation contexts). Velux-only conversions are possible where ridge height allows. We recommend the best structural and planning route at survey.
We cover all Westminster postcodes — {postcodes} — with surveyors based locally. Survey appointments within 3 working days. Our structural engineer is London-based and attends site when required.
Most Westminster loft conversions require Party Wall notices to adjoining neighbours — typically for steel beam installation and/or raising the party wall. We can co-ordinate the notice process; our in-house engineer handles the structural element. The Act gives neighbours 14 days to respond.
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. Westminster's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards ...
From £995. Turn your unused Westminster garage into a bedroom, home office or open-plan kitchen-diner. Planning route assessment, f...
From £1,950. Full architectural technology service for basement digs and cellar conversions in Westminster — structural underpinning ...
From £350. Chartered structural engineer calculations for every residential intervention in Westminster — steel beams, lintels, pad...
From £540. Fixed-fee measured surveys across Westminster from £540 — floor plans, elevations and sections to ±3mm accuracy. Leica D...
From £450. End-to-end Party Wall Act 1996 service for Westminster — Section 1, 3 and 6 notices, schedule of condition surveys, part...
From £1,225. London's most popular loft type — the full-width rear dormer. Planning or Permitted Development route assessed for your ...
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