London's most popular loft type — the full-width rear dormer. Planning or Permitted Development route assessed for your City of London property, building regulations, structural steelwork and Party Wall notices.
For City of London homeowners in Very limited residential — Barbican Estate (listed post-war), a rear dormer drawings package is the full measured-survey-to-submission drawing set City of London Corporation needs in order to determine an application: existing and proposed plans, elevations and sections at 1:100 and 1:50, a location and site plan, and the supporting statements the case officer asks for.
Prepared and reviewed by the chartered technologist team at Architectural Drawings London — MCIAT chartered, £2m PI insured.Last reviewed 2026-08-03.


London's most popular loft type — the full-width rear dormer. Planning or Permitted Development route assessed for your City of London property, building regulations, structural steelwork and Party Wall notices.
Housing stock in City of London: Very limited residential — Barbican Estate (listed post-war), Golden Lane Estate, modern luxury flats; overwhelmingly commercial.
Character: Overwhelmingly commercial; residential planning extremely constrained; listed building density the highest of any London borough.
Article 4: Multiple Article 4 Directions around office-to-residential, demolition, and shopfront changes.
We confirm whether your City of London rear dormer qualifies for Permitted Development — checking volume limits (40m³ terraced, 50m³ semi/detached), Article 4, conservation area and prior extension history.
If PD applies, we obtain a Lawful Development Certificate for certainty. If not, we submit full planning with Design & Access Statement to City of London Corporation.
Full-width flat-roof rear dormer with matching materials, set in from party walls, cheeks clad to match existing roof — the design that City of London Corporation approves most readily.
Part B fire escape (protected staircase, fire doors, smoke alarms), Part K staircase, Part L insulation, Part E acoustic separation.
Steel ridge beam, purlin supports, dormer framing, floor joist upgrade — chartered engineer sign-off for Building Control.
Most rear dormers in City of London's terraced streets trigger Section 6 Party Wall notices. We draft, serve and coordinate the process.

Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Move the controls for an indicative figure. It anchors your budget — it is not a quote. Every project is priced after a free survey.
Build costs are separate and quoted by your contractor. See our published fees.
Every City of London postcode district we draw in, the stock that dominates it and the authority that validates a rear dormer there. City of London fees below are the statutory England rates for 2026, not rear dormer estimates.
| Postcode | Area | Dominant stock | What it means for a rear dormer |
|---|---|---|---|
| EC1A | Smithfield | Mostly commercial, residential lofts | EC1A covers Smithfield only; City of London Corporation handles the rear dormer, and Smithfield case officers apply the EC1A conservation-area map. |
| EC2Y | Barbican | Listed Brutalist apartments (Barbican Estate) | EC2Y covers Barbican only; City of London Corporation handles the rear dormer, and Barbican case officers apply the EC2Y conservation-area map. |
| EC3N | Tower Hill / Aldgate | Very limited residential — Barbican Estate (listed post-war) | EC3N covers Tower Hill / Aldgate only; City of London Corporation handles the rear dormer, and Tower Hill / Aldgate case officers apply the EC3N conservation-area map. |
| EC4M | St Paul's | Mostly commercial, listed residential | St Paul's sits wholly inside EC4M, so City of London Corporation validates every rear dormer submitted from an EC4M address. |
| EC4V | Blackfriars | Very limited residential — Barbican Estate (listed post-war) | Blackfriars sits wholly inside EC4V, so City of London Corporation validates every rear dormer submitted from an EC4V address. |
| EC4Y | Temple | Very limited residential — Barbican Estate (listed post-war) | A rear dormer at an EC4Y address in Temple is determined by City of London Corporation under its own Local Plan policies for Temple. |
| EC2A | Shoreditch | Warehouse conversions, modern infill | EC2A straddles a boundary: Shoreditch addresses fall to Hackney Council or City of London Corporation, so confirm which authority validates the rear dormer before submitting EC2A drawings. |
Roof pitch, wall build-up and plot depth change every few City of London streets, and each one changes what a rear dormer can achieve at that address.
City of London conservation designations: there are 27 across City of London Corporation, Fleet Street, Whitefriars, St Paul's among them. Designation costs a City of London owner the permitted-development route: a rear dormer then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Fleet Street is the City of London designation that most often changes a rear dormer design.
City of London and Article 4: Multiple Article 4 Directions around office-to-residential, demolition, and shopfront changes. A rear dormer planned at a EC1A address is checked against that direction first; City of London Corporation publishes the City of London extent, and the EC1A line rarely follows the City of London boundary you would expect.
The building fabric around City of London: Very limited residential — Barbican Estate (listed post-war), Golden Lane Estate, modern luxury flats; overwhelmingly commercial. Overwhelmingly commercial; residential planning extremely constrained; one of the two highest listed-building densities in London. A rear dormer in City of London is scoped against that stock first, because it decides whether the scheme runs as permitted development, a £274 Lawful Development Certificate, or a full £548 application to City of London Corporation.
Sources for this City of London rear dormer page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
Direct answers to the questions City of London homeowners ask every week about rear dormer drawings.
Start a free quote →It depends on your exact address in City of London. 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 City of London 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. Full-width rear dormers are the most common PD loft type in City of London — provided the volume, materials and setback conditions are met. We check every condition before committing to a route.
A City of London rear dormer has two cost lines: our architectural package (drawings, building regulations and structural calculations, quoted as one fixed figure) and the build, which moves with access, floor area and specification — an en-suite adds plumbing runs and drainage. See our fees.
A full-width rear dormer in City of London typically adds 15–25 square metres of habitable floor area — enough for a double bedroom with en-suite, or two single bedrooms. The flat roof gives full standing height across the entire width of the house, unlike a rooflight-only conversion which is constrained by the roof pitch.
Rear dormers in City of London's conservation areas usually need full planning permission because PD rights are restricted. However, because they face the rear (not the street), City of London Corporation typically views them more favourably than front dormers or mansards. A well-designed rear dormer with matching materials and sensitive proportions has a strong approval record.
A standard rear dormer in City of London takes 8–12 weeks to build once on site. Our architectural package takes 3–5 weeks from instruction to submission. Building Control approval adds 2–4 weeks. Total timeline from survey to move-in: approximately 4–5 months.

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