Rear extension drawings for a Rainham RM13 semi-detached house, London Borough of Havering

Rainham · RM13 · Havering

Mansard Loft Conversion Drawings in Rainham RM13

Fixed-fee, MCIAT-chartered mansard loft conversion drawings for Rainham (RM13) homeowners — London Borough of Havering validation and local constraints handled from the start.

Rainham is an outer-east Havering neighbourhood in RM13 where a small historic village core sits within broad interwar and post-war housing estates stretching toward the marshes. The bulk of our work here is rear and side-return extensions, loft conversions and garden-facing kitchen extensions on family semis and terraces that generally fall within permitted development.

Around the Rainham Village conservation area near Rainham Hall and the church, permitted development rights are trimmed and materials matter, so we detail those schemes to the standard London Borough of Havering expects while keeping the everyday suburban streets efficient and fully compliant.

Proposed floor plan

Rainham RM13

Rainham (RM13) — planning at a glance

Council: London Borough of Havering
Postcode district: RM13
Planning portal: View the Havering planning portal
Housing stock: Rainham pairs a tight historic core near Rainham Hall and the medieval church with wide belts of 1930s and post-war semi-detached and terraced housing running out toward the marshes. Most homes are unlisted family houses with generous rear gardens, well suited to rear extensions, side infills and loft conversions.
Article 4: London Borough of Havering does not publish its Article 4 directions to the national planning register, so permitted development rights in Rainham (RM13) can’t be confirmed from open data alone — we check the direction schedule with the council before recommending a route, as part of the fixed fee. No published householder Article 4 direction; the main control is the Rainham Village conservation area around the historic core.
Conservation: Rainham Village
Sample streets: Upminster Road North · Lambs Lane South · Brookway · Elizabeth Road
Local constraints: Rainham Village conservation area tightens design and materials in the historic corepredominantly interwar and post-war suburban stock where permitted development often applies away from the coreproximity to the Rainham marshes and Thames floodplain raises surface-water and flood-risk considerations on lower-lying plotsmature street trees on the residential avenues can carry TPO or root-protection implications

Planning in Rainham (RM13): what to know before you apply

No published householder Article 4 direction applies in Rainham; the principal constraint is the Rainham Village conservation area, and lower-lying plots near the marshes can attract flood-risk scrutiny. Most surrounding interwar and post-war houses retain normal permitted development rights.

Typical Rainham housing stock

Rainham pairs a tight historic core near Rainham Hall and the medieval church with wide belts of 1930s and post-war semi-detached and terraced housing running out toward the marshes. Most homes are unlisted family houses with generous rear gardens, well suited to rear extensions, side infills and loft conversions.

Streets we regularly draw for in Rainham

Upminster Road North · Lambs Lane South · Brookway · Elizabeth Road

What RM13 is actually built of

Measured from 361 classified residential buildings in RM13, not from a description of the area.

Rainham RM13 housing mix

Residential building form across the RM13 postcode district, from 361 classified buildings.

Attached on more than one side	36%
Attached on one side	49%
Detached	15%
Median building footprint	61 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate	1.46
Buildings classified	361

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-08-17.

Mansard Loft Conversion Drawings for Rainham (RM13) homes: the package and the process

A mansard is a rebuild of the roof, so the drawings carry more structure than a dormer scheme: the new front and rear slopes with their pitch angles set out, the upstand and party wall junctions, the parapet and gutter detail, and a street-scene elevation showing the new roof against its neighbours.

That street scene usually decides the application. Where a terrace already has approved mansards, the drawing shows the new roof matching their line, pitch and window rhythm; where it would be the first, the case is made on the roof form itself. Either way the argument is drawn, not written.

Mansards belong to terraces and to parapeted stock. The form works because a near-vertical rear wall can rise off the party walls and sit behind a parapet, which is why it is the usual answer in tightly controlled streets and rarely the right answer on a detached house.

What is a mansard loft conversion?

A mansard replaces the rear roof slope — or, less commonly, the front and rear slopes together — with a new near-vertical wall rising from the party walls to a shallow flat roof at the ridge, with small dormer windows set into it. Unlike a dormer, which sits within the existing roof, a mansard changes the shape of the roof itself, which is why it is usually reserved for terraces where the extra headroom and floor area are worth the more involved planning and construction process. Because the new wall runs almost the full width of the house between the party walls, a mansard typically delivers noticeably more usable floor area than a single dormer of any kind, which is why it remains the preferred option on period terraces where every square metre of loft counts.

Does a mansard loft conversion need planning permission in London?

Yes, almost always. Permitted development rights for roof alterations are volume- and shape-limited, and a mansard goes well beyond what those limits allow because it materially alters the roof's profile rather than adding to it. Every mansard we draw is prepared as a full householder planning application, with a design and access statement where the borough requires one, so the council can properly assess the change to the roofline and its impact on neighbours and the street scene.

Why do conservation areas favour mansards?

Many London conservation areas already contain mansard roofs as part of the original streetscape — grand Georgian and Victorian terraces were frequently built with a mansard attic storey behind a parapet, so a matching modern mansard often reads as a restoration of the intended roofline rather than an alteration. Getting that read right depends on matching the existing slate or tile colour, the proportion and spacing of the dormer windows, and the eaves and parapet detailing of the host terrace — details we design in from the first drawing rather than treating as an afterthought.

Slate or tile colour and coursing matched to the existing roof and neighbouring properties
Dormer window proportions and spacing aligned to the terrace's existing rhythm
Eaves, parapet and party wall junctions detailed to sit flush with neighbouring roofs

Typical mansard loft conversion drawing packages
Package	Scope	Planning route	Fee from
Rear mansard, planning only	Design, planning drawings and supporting statement	Householder planning	£1,600
Rear mansard, planning and building regs	Planning drawings plus structural and Part L detailing	Householder planning	£2,200
Front and rear mansard	Full roof rebuild on both slopes, with structural	Householder planning	£2,400

Sheet from a mansard loft conversion drawings package drawn for a Rainham property in RM13, showing the existing and proposed arrangement at scale — A sheet from the mansard loft conversion drawings package we submit to London Borough of Havering for Rainham (RM13) properties.

Also in Rainham RM13

Planning Permission Planning Drawings Architectural Drawings Building Regulations Drawings Loft Conversion Drawings Mansard Loft Conversion Drawings across Havering Mansard Loft Conversion Drawings across London

FAQ

Mansard Loft Conversion Drawings in Rainham RM13 — FAQs

How much do mansard loft conversion drawings cost in London?+

Planning drawings for a rear mansard typically start around £1,600. A combined planning and building regulations package, or a front-and-rear mansard, usually runs to around £2,200–£2,400 once structural calculations are included.

Can a mansard ever be permitted development?+

Rarely — because it changes the shape of the roof rather than adding within it, a mansard almost always exceeds permitted development tolerances. If you want to avoid a full application, ask us whether a dormer or hip-to-gable conversion would meet your space needs instead.

How long do mansard drawings take?+

A full planning drawing set is typically ready within about 10–14 days of survey, reflecting the extra design and consultation work a full roof rebuild involves. The statutory 8-week householder determination period then runs from validation.

Will a mansard need scaffolding and affect the whole roof?+

Yes — because the existing rear roof slope is removed and rebuilt, a mansard is a larger construction project than a dormer, and we design the sequencing and structural tie-ins with that in mind so your builder can programme the work efficiently.

Do you handle the party wall process as well as the drawings?+

We identify which neighbours require notice under the Party Wall etc. Act 1996 and provide the drawings needed to support the notice, so the party wall and planning processes can run in parallel rather than one waiting on the other.

Do I need planning permission for an extension in Havering?+

Havering has no borough-wide Article 4 direction affecting typical householder permitted development, so its detached and semi-detached homes often keep fuller rights than inner-London terraces — larger rear and single-storey extensions can qualify. Green-belt land toward the east and conservation areas such as Upminster and Emerson Park restrict this. We check your address first and can confirm permitted development with a Lawful Development Certificate.

How does green-belt land affect my Havering project?+

On green-belt properties toward the borough's eastern and northern edges, extensions are assessed against strict limits on disproportionate additions to the original dwelling. It does not rule out an extension, but scale and siting matter and the case must be evidenced carefully. We confirm whether your property is green belt and design a scheme that stays within policy.

Can I build a bigger extension because Havering plots are larger?+

Often, yes. The generous interwar and detached plots across Hornchurch, Emerson Park and Upminster make substantial rear and double-storey extensions viable where a tight terrace could not. The limit is usually policy rather than space. We design to use the plot fully within permitted-development allowances or a well-evidenced full application.

How long does Havering Council take to decide?+

Havering determines most householder applications within the statutory eight-week period once validated; green-belt and conservation cases can involve additional consultation. A complete, correctly scaled submission is the best way to avoid a validation query — we prepare Havering drawings to the council's checklist to keep the application on track.

How much do planning drawings cost in Havering?+

We quote a fixed fee upfront, typically around 30% below an architect's charge for the same council-accepted drawings, with free redraws until Havering approves. Because plots here allow larger schemes, the fee tracks complexity — a single-storey rear differs from a double-storey or a green-belt case — and we confirm it once we understand your plans.

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