Mansard Roof Extensions · BR2 Hayes
Fixed-fee mansard roof extensions for Hayes, Bromley Common, Keston, Bickley fringe in the BR2 postcode, drawn by an MCIAT-chartered architectural technologist and submitted to Bromley Council. Bromley protects the Hayes Village and Keston conservation areas and the surrounding metropolitan green belt and commons, alongside standard householder control across BR2.
MCIAT chartered drawings for planning, building regs, lofts and extensions — fixed fees 30% below typical London architects. Tell us what you need and we’ll reply the same working day.
A mansard roof extension adds a full storey behind a new sloping front face — a strong option on BR2's terraces in Hayes where a standard dormer is too small. Bromley Council scrutinises mansards on townscape and precedent, especially within Hayes Village, Keston; we design to the borough's roof guidance with a Heritage Statement where the setting requires it.
Hayes's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Hayes conservation areas — with heritage statements and planning officer negotiation built in.
Across Hayes, Bromley Common, Keston, Bickley fringe in BR2, the dominant property is inter-war and edwardian semis and detached houses around hayes and bromley common, with larger plots toward keston and the green belt. That stock shapes what mansard roof extensions looks like here: the right approach for a period terrace differs from a mansion-block flat or a new-build, and Bromley Council judges each on design quality and neighbour impact. We survey the specific Hayes property, confirm the planning route — Permitted Development, a Lawful Development Certificate, or full planning — and draw a council-ready set tailored to the BR2 streetscape.
Housing stock in BR2: Inter-war and Edwardian semis and detached houses around Hayes and Bromley Common, with larger plots toward Keston and the green belt.
Within the district: Hayes, Bromley Common, Keston, Bickley fringe.
Streets we know in BR2: the Hayes village streets, the roads around Hayes Common and the larger plots toward Keston. Each road has its own building line, boundary treatment and precedent that Bromley Council weighs when assessing a mansard roof extensions scheme.
Conservation areas: Hayes Village, Keston. Inside these, most external work needs full planning and a Heritage Statement.
Getting around BR2: Hayes (the Hayes line terminus) into Charing Cross and Cannon Street.
Property values: around £325,000 for a flat and £600,000-£1.1m for a house — a useful gauge of the build value an extension or loft adds in BR2.
Borough character: Largest London borough by area; substantial Green Belt; conservation areas in most town centres; generally permissive elsewhere.
We check against Bromley Council's mansard design guide and design to match the terrace.
Required for Hayes's conservation areas — demonstrates the mansard respects character and townscape.
Accurate photomontage showing how the mansard sits alongside neighbours — often decisive at Bromley Council committee.
Mansards invariably trigger Party Wall notices in Hayes's dense terraced streets. Structural package includes new ridge, tie beams, floor joists.
Full liaison with Bromley Council planning officer, committee representation if called in.
Part L thermal, Part B fire (critical on mansards), Part E acoustic separation.
Single planning or building-regs submission.
Planning + building regs + structural.
Listed, conservation or complex sites.
Because BR2 is a leafy family market of inter-war and Edwardian semis and detached houses on generous plots around Hayes and Keston — ideal for substantial rear, side and wrap-around extensions and loft conversions. Outside the conservation areas and green belt, much runs on the Permitted Development route, confirmed with a Lawful Development Certificate.
Properties on the edge of Hayes Common, Keston Common or the metropolitan green belt face tighter limits on extending the footprint, so we check whether your plot is washed over by green belt before designing. Within the built-up area, normal householder and PD rules apply, which we confirm at survey.
Usually yes on the semis and detached houses outside the conservation areas — a hip-to-gable plus rear dormer within the volume allowance, confirmed by a Lawful Development Certificate. The generous BR2 roofs often give good head height. We draw the scheme for Building Control too.
With BR2 houses around £600,000-£1.1m and a direct line to Charing Cross, a rear or loft extension adds family space worth above the build and drawing cost. BR2's green, village-edge setting is highly sought after, and our fixed fee keeps the cost predictable.
Our fixed fee for mansard roof extensions in Hayes starts at £1,575 — no hourly billing. With Hayes property at around £325,000 for a flat and £600,000-£1.1m for a house, the professional drawing fee is a small fraction of the value the work adds to BR2's inter-war and edwardian semis and detached houses. Bromley Council charges its own statutory application fee on top (currently £258 for a householder planning application, £578 for a full application). We quote the drawings as one fixed price and the free site survey covers every BR2 address.
For a BR2 project across Hayes, Bromley Common, Keston, Bickley fringe, expect roughly 3–4 weeks from instruction to submission: week 1 the measured survey, weeks 2–3 the drawings and your revisions, then validation and the statutory determination by Bromley Council (8 weeks for a householder application). We carry the Hayes application through every officer query to the decision.
Hayes (BR2) sits primarily in Bromley, so applications are decided by Bromley Council. Article 4 in force in the borough: No. Conservation areas within BR2 include Hayes Village, Keston, where full planning and a Heritage Statement are required. We confirm the planning route for your exact address before quoting.
Almost always. Any structural work behind mansard roof extensions in Hayes — new openings, steel beams, loft floors, foundations — needs Building Regulations approval covering structure (Part A), fire escape (Part B) and insulation (Part L), submitted to Bromley Council Building Control or an approved inspector. On BR2's typically terraced and semi-detached stock, a Party Wall notice to adjoining neighbours is normally required before the steelwork. We coordinate both as part of the Complete package.
In value terms, yes. With Hayes (BR2) property at around £325,000 for a flat and £600,000-£1.1m for a house, a well-designed extension or loft typically returns more than it costs in added floor area and sale value, while our fixed drawing fee from £1,575 keeps the professional cost predictable. The bigger risk is an unapproved or non-compliant scheme — which is why council-ready drawings and a clean Building Control sign-off matter on BR2 homes.
From £840.
From £840.
From £1,225.
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From £995.
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Pick a slot that suits you. No obligation and no sales pressure — just straight answers on your planning route, fixed fee and timescale.
Every BR2 postcode district we draw in, the stock that dominates it and the authority that validates a mansard roof extension there. BR2 fees below are the statutory England rates for 2026, not mansard roof extension estimates.
| Postcode | Area | Dominant stock | What it means for a mansard roof extension |
|---|---|---|---|
| BR2 | Hayes / Keston | Victorian terraces, Edwardian villas, post-war flats | A mansard roof extension at an BR2 address in Hayes / Keston is determined by Bromley Council under its own Local Plan policies for Hayes / Keston. |
| BR2 | Bromley | Victorian terraces, Edwardian villas, post-war flats | Bromley sits inside BR2; mansard roof extension proposals here are determined by Bromley Council. |
| BR2 | Keston | Edwardian villas, 1930s semi-detached | Keston sits inside BR2; mansard roof extension proposals here are determined by Bromley Council. |
| SE20 | Anerley / Penge | Victorian and Edwardian terraces | Adjoining district to BR2, also inside Bromley for mansard roof extension purposes. |
| BR1 | Bromley / Bickley | Victorian terraces, Edwardian villas, post-war flats | Adjoining district to BR2, also inside Bromley for mansard roof extension purposes. |
| BR3 | Beckenham | Edwardian villas, 1930s semi-detached | Adjoining district to BR2, also inside Bromley for mansard roof extension purposes. |
Roof pitch, wall build-up and plot depth change every few BR2 streets, and each one changes what a mansard roof extension can achieve at that address.
BR2 (Hayes / Keston) conservation designations: there are 48 across Bromley Council, Keston, Bickley, Bromley Town among them. Designation costs a BR2 (Hayes / Keston) owner the permitted-development route: a mansard roof extension then needs a £258 householder application over 8 weeks, in place of the £120 prior approval route that takes 6 weeks. Bromley Town is the BR2 (Hayes / Keston) designation that most often changes a mansard roof extension design.
Article 4 and your BR2 (Hayes / Keston) mansard roof extension: Bromley Council has made no borough-wide direction, so permitted development for a mansard roof extension in BR2 (Hayes / Keston) generally survives outside BR2 (Hayes / Keston) conservation areas and listed curtilages. A Lawful Development Certificate at £129 is how a BR2 owner records that a mansard roof extension was lawful.
What BR2 (Hayes / Keston) is built from: Large 1930s detached and semi-detached in Chislehurst and Bickley; Edwardian in Beckenham; Victorian in Bromley town; Metropolitan Green Belt covers significant rural-fringe land. Largest London borough by area; substantial Green Belt; conservation areas in most town centres; generally permissive elsewhere. That mix decides the mansard roof extension route in BR2 (Hayes / Keston) more than the postcode does. Our fixed fee for mansard roof extensions in BR2 (Hayes / Keston) starts at £1,575, against £1,750 for the Complete package that carries a BR2 (Hayes / Keston) scheme through Bromley Council planning and building regulations together.
Sources for this BR2 mansard roof extension 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.
Free fixed quote in 60 seconds. From £1,575. MCIAT chartered.
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