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House extension plans in Wales — a glazed single-storey rear extension on a period home
Wales · House Extension Drawings & Planning

House extension plans in Wales

Single-storey, double-storey, rear and side extension drawings for Wales homes — measured to Rotherham Metropolitan Borough Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.

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Wales householder planning by the numbers

Rotherham Metropolitan Borough Council granted 71% of the householder planning decisions it made in its latest published year — 16 points below the 87% England-wide householder average. Wales contains Harthill, Wales conservation areas (Harthill designated 1976), so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant postwar (1945–1970) housing stock sets the design brief on most streets.

Under Class B, a rear dormer stays permitted development up to 40m³ of added roof volume on a terrace or 50m³ on a semi-detached or detached house, while Class A allows a single-storey rear extension of 3m beyond the original rear wall on a terrace and 4m on a detached house before a full application is needed. In conservation areas such as Harthill and Wales those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Wales is determined against an 8-week statutory target.

Harthill (conservation area designated in 1976), Wales (conservation area designated in 1976) and Harthill with Woodall (civil parish within Wales) — these are the Wales pockets our drawings cover most. Heritage designations here include Harthill and Wales. Rotherham Metropolitan Borough Council weighs each proposal against Rotherham Metropolitan Borough Council's adopted local plan and its householder design guidance, where the 4,600 homes here are 15% 1965-1972, 11% 2000-2008, 10% 1993-1999, which is what sets the realistic roof and rear-projection options. On roofs the borough is shallow-pitched roofs and integral garages typical of that period's building and trussed-rafter roofs typical of 2000s building, over late-1960s and early-1970s houses (15% of 4,600 homes), 2000s houses and apartments (11%) and 1990s estate houses (10%).

What actually constrains a project in Wales

Wales's designated heritage is specific, and it is the first thing we check against your address: Harthill (conservation area designated in 1976) and Wales (conservation area designated in 1976). Inside those boundaries permitted development is curtailed and Rotherham Metropolitan Borough Council assesses materials, window detail and roof form against the area's own appraisal, so a scheme that would be waved through two streets away can need a full application here.

Beyond the designated areas, Wales takes in Harthill with Woodall. No Article 4 direction is recorded for Rotherham Metropolitan Borough Council, but Wales's 2 conservation areas still limit permitted development on those streets.

On stock, Wales is late-1960s and early-1970s houses (15% of 4,600 homes), 2000s houses and apartments (11%) and 1990s estate houses (10%) — which is why shallow-pitched roofs and integral garages typical of that period's building and trussed-rafter roofs typical of 2000s building govern what a loft or rear projection can realistically be. Rotherham Metropolitan Borough Council decided 402 householder applications in the latest published year and granted 71%, with 72% issued inside the eight-week target. Those are the numbers our drawings are prepared against.

The full build-period split for Wales runs pre-1900 6% (290 homes), 1900-1918 8% (370 homes), 1919-1929 9% (400 homes), 1930-1939 4% (180 homes), 1945-1954 9% (430 homes), 1955-1964 7% (310 homes), 1965-1972 15% (670 homes), 1973-1982 4% (170 homes), 1983-1992 8% (370 homes), 1993-1999 10% (440 homes) and 2000-2008 11% (500 homes). That distribution is why pre-1900 detailing dominates the drawings here, and it is measured from council-tax records rather than assumed from the street name.

Rotherham Metropolitan Borough Council also decides for Anston & Woodsetts, Aston & Todwick, Aughton & Swallownest, Boston Castle, Bramley & Ravenfield, Dalton & Thrybergh, Dinnington and Hoober, so a decision in Wales sits inside a wider pattern of decisions we track across the same authority — useful when an officer cites a precedent from the next area over.

Wales in numbers — housing stock and planning decisions

Published figures for Wales and Rotherham Metropolitan Borough Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.

MeasureWales
Dwellings recorded4,600
Built pre-1900290 (6%)
Built 1900-1918370 (8%)
Built 1919-1929400 (9%)
Built 1930-1939180 (4%)
Built 1945-1954430 (9%)
Built 1955-1964310 (7%)
Built 1965-1972670 (15%)
Built 1973-1982170 (4%)
Built 1983-1992370 (8%)
Built 1993-1999440 (10%)
Built 2000-2008500 (11%)
Built before 191914%
Built 1919–193913%
Built 1945–200863%
Conservation areas in Wales2 (Harthill, Wales)
Conservation areas district-wide28
Article 4 directions recorded0
Householder applications decided402
Householder applications granted71%
Decided within 8 weeks72%

Dwelling stock from VOA council-tax data at 31 March 2025; conservation-area and Article 4 counts from planning.data.gov.uk (MHCLG); decision figures are Rotherham Metropolitan Borough Council's own, from MHCLG live table PS2 for the year to 31 March 2026.

Extension plans built around Rotherham Metropolitan Borough Council's rules

Wales homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from late-1960s and early-1970s houses (15% of 4,600 homes), 2000s houses and apartments (11%) and 1990s estate houses (10%), so a Victorian terrace usually wants a rear or side-return infill, while an interwar semi has room for a wider single-storey wrap or a two-storey side addition. Rotherham Metropolitan Borough Council judges every one of them against Rotherham Metropolitan Borough Council's adopted local plan and its householder design guidance, weighing footprint, height and the impact on the house next door before it looks at the elevations.

That is why the drawings decide the outcome. We set the extension depth against the permitted-development limits precisely, keep the eaves and ridge within the allowances, and plot the 45-degree daylight lines to the neighbours' windows so the case officer can see the amenity test is passed. Wales contains Harthill, Wales conservation areas (Harthill designated 1976), so materials, fenestration and roof form are assessed against the appraisal, so we design around it from the first sketch rather than discover it at validation.

Wales also protects whole streets — Harthill and Wales among them. No Article 4 direction is recorded for Rotherham Metropolitan Borough Council, but Wales's 2 conservation areas still limit permitted development on those streets. On designated land the larger-home extension route and most side extensions stop being permitted development, so we confirm your address against those layers before drawing a line.

Isometric house extension drawing for a Wales home

Do I need planning permission to extend my house in Wales?

Plenty of Wales extensions are permitted development and need no planning application — a single-storey rear extension within the depth and height limits is the common case. You will normally need to apply to Rotherham Metropolitan Borough Council if any of these apply:

  • The single-storey rear extension is deeper than 3 metres on a terrace or semi, or 4 metres on a detached house (6m/8m needs prior approval under the larger-home scheme)
  • It is a two-storey or double-storey extension, or the rear extension is higher than 4 metres
  • A side extension is wider than half the original house, or more than one storey
  • Any part projects forward of the principal (front) elevation, or the extension covers more than half the garden
  • Your home is in a conservation area such as Harthill and Wales, where the larger-home route and side extensions are not permitted development

Wales extension approval rates — live from council data

Below is Rotherham Metropolitan Borough Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Rotherham Metropolitan Borough Council granted 71% of its householder applications in the year to 31 March 2026, and Harthill shapes what is approved here. A complete, policy-literate extension pack anticipates those pressure points before submission, which is why professionally drawn applications are decided faster and refused less often than DIY ones.

Source: MHCLG planning application statistics (householder decisions, England, 1 April 2025 - 31 March 2026). Compare every borough on our London approval-rate league table.

71%householder applications approved in Rotherham
87%national average — Rotherham is 16 points below the national average

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Which extensions get approved in Wales

Across Harthill, Wales and Harthill with Woodall, the extension that lands most often is the single-storey rear addition — a glazed kitchen-diner across the back of the house, kept within the permitted-development depth or taken to a full application where the ground floor wants more. On the borough's late-1960s and early-1970s houses (15% of 4,600 homes), a side-return infill frequently pairs with it to square off the plan; on wider 1990s estate houses (10%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.

The 4,600 homes here are 15% 1965-1972, 11% 2000-2008, 10% 1993-1999, which is what sets the realistic roof and rear-projection options. We size the extension to the amenity and daylight tests, match the roof and materials to the host house, and keep enough garden to satisfy Rotherham Metropolitan Borough Council's space standards — so the scheme answers the borough's questions before an objection can raise them. Where permitted-development rights are used up or removed, we prepare the householder application to the council's extension design guidance instead.

Single-storey rear extension opening onto the garden of a Wales house

House extensions across Wales

We draw extensions on every street in the borough. A few of the neighbourhoods where Wales projects come up most often:

Harthill

Extension drawings for Harthill's conservation area designated in 1976 — footprint-checked, daylight-tested and drawn to Rotherham Metropolitan Borough Council's guidance.

Wales

Extension drawings for Wales's conservation area designated in 1976 — footprint-checked, daylight-tested and drawn to Rotherham Metropolitan Borough Council's guidance.

Harthill with Woodall

Extension drawings for Harthill with Woodall's civil parish within Wales — footprint-checked, daylight-tested and drawn to Rotherham Metropolitan Borough Council's guidance.

Which extension suits your Wales home?

The right extension in Wales depends on your house type and how much garden you can give up. This is how the main options compare on planning route and what they add.

Extension typePermitted development?What it addsWhat Rotherham Metropolitan Borough Council checks
Single-storey rearOften, within 3m/4m depth (6m/8m via prior approval)Bigger kitchen-diner across the backDepth, height, neighbour daylight (45°)
Side-return infillSometimes, if within width and height limitsSquares off an L-shaped ground floorWidth vs the original house, glazing to boundary
Two-storey rear/sideNo — full applicationExtra bedroom or bathroom aboveBulk, overlooking, 7m rear-boundary gap
Wraparound (rear + side)No — full applicationWhole-width open-plan ground floorCombined footprint and garden retained

Route depends on your street — conservation areas such as Harthill and Wales and Article 4 directions can remove permitted-development rights.

Four steps to an approved Wales extension

A fixed process built around how Rotherham Metropolitan Borough Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.

  1. 1

    Free approval check

    Tell us your Wales postcode and house type. We confirm your conservation and Article 4 status, how much permitted-development depth you have left, and score your odds against live Rotherham Metropolitan Borough Council decisions.

  2. 2

    Measured survey

    We measure the existing footprint, floor and eaves levels, boundary distances and the neighbours' window positions — the numbers the depth limits and daylight tests depend on.

  3. 3

    Extension design & drawings

    Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Rotherham Metropolitan Borough Council's extension design guidance.

  4. 4

    Submission & follow-through

    We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Rotherham Metropolitan Borough Council issues its decision.

Frequently asked questions

Do I need planning permission to extend my house in Wales?

Not always. A single-storey rear extension up to 3 metres deep on a terrace or semi, or 4 metres on a detached house, and no higher than 4 metres, is usually permitted development. In Wales you will need to apply to Rotherham Metropolitan Borough Council for two-storey extensions, side extensions wider than half the house, anything forward of the front wall, deeper rear extensions under the larger-home prior-approval route, and any extension in a conservation area such as Harthill and Wales.

How deep can a single-storey rear extension go in Wales without planning permission?

Standard permitted development allows 3 metres on a terraced or semi-detached house and 4 metres on a detached one. The larger-home extension scheme can double that to 6 or 8 metres, but it needs a prior-approval notification to Rotherham Metropolitan Borough Council and a neighbour-consultation period, and it does not apply on designated land such as Wales's conservation areas. We confirm which route your property qualifies for before drawing.

Can I build a double-storey extension in Wales?

Two-storey and double-storey extensions almost always need a full householder application to Rotherham Metropolitan Borough Council, because they fall outside permitted development on most homes. The council looks closely at bulk, overlooking of neighbours and the 7-metre gap a two-storey rear extension must keep from the rear boundary. We design to those tests and show the daylight and privacy angles on the drawings. This applies to your Wales address specifically.

How long does Rotherham Metropolitan Borough Council take to decide an extension application?

A householder planning application in Wales runs to a statutory eight-week target, a larger-home prior-approval notification to around six weeks including the neighbour-consultation period, and a lawful development certificate to eight weeks. Incomplete submissions stall at validation, so we submit a complete pack and manage officer queries to keep the decision on schedule. Rotherham Metropolitan Borough Council is the decision-maker.

Will my extension in Wales need building regulations approval as well as planning?

Yes — planning permission and building regulations are separate consents, and almost every extension needs both. Planning governs whether you can build it; building control governs how it is built, covering structure, insulation, drainage and fire safety. We prepare the building-regulations drawings alongside the planning set so Rotherham Metropolitan Borough Council's building control or an approved inspector can sign the work off. This applies to your Wales address specifically.

How much do extension plans in Wales cost?

Every house and brief is different, so we price each Wales extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Rotherham Metropolitan Borough Council approves, and we tell you upfront whether your extension qualifies as permitted development. Call 020 7864 7245 to get started.

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House extension plans across Rotherham

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