Single-storey, double-storey, rear and side extension drawings for Roby homes — measured to Knowsley Metropolitan Borough Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
Knowsley Metropolitan Borough Council granted 95% of the householder planning decisions it made in its latest published year — 8 points above the 87% England-wide householder average. Roby contains Roby, St Michaels Church, The Orchard conservation areas (Roby designated 2015), so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant interwar (1918–1939) and 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 Roby, St Michaels Church and The Orchard those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Roby is determined against an 8-week statutory target.
Roby (conservation area designated in 2015), St Michaels Church (conservation area designated in 2019) and The Orchard (conservation area designated in 2014) — these are the Roby pockets our drawings cover most. Heritage designations here include Roby, St Michaels Church and The Orchard. Knowsley Metropolitan Borough Council weighs each proposal against Knowsley Metropolitan Borough Council's adopted local plan and its householder design guidance, where the 4,110 homes here are 24% 1955-1964, 22% 1930-1939, 12% 1983-1992, which is what sets the realistic roof and rear-projection options. On roofs the borough is shallow gabled roofs typical of that period's building and hipped roofs with shallow pitches typical of 1930s building, over late-1950s and early-1960s houses (24% of 4,110 homes), 1930s semi-detached and detached houses (22%) and 1980s estate houses (12%).
Roby's designated heritage is specific, and it is the first thing we check against your address: Roby (conservation area designated in 2015), St Michaels Church (conservation area designated in 2019) and The Orchard (conservation area designated in 2014). Inside those boundaries permitted development is curtailed and Knowsley 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.
No Article 4 direction is recorded for Knowsley Metropolitan Borough Council, but Roby's 3 conservation areas still limit permitted development on those streets.
On stock, Roby is late-1950s and early-1960s houses (24% of 4,110 homes), 1930s semi-detached and detached houses (22%) and 1980s estate houses (12%) — which is why shallow gabled roofs typical of that period's building and hipped roofs with shallow pitches typical of 1930s building govern what a loft or rear projection can realistically be. Knowsley Metropolitan Borough Council decided 167 householder applications in the latest published year and granted 95%, with 60% issued inside the eight-week target. Those are the numbers our drawings are prepared against.
The full build-period split for Roby runs pre-1900 3% (130 homes), 1900-1918 0% (20 homes), 1919-1929 1% (30 homes), 1930-1939 22% (910 homes), 1945-1954 8% (340 homes), 1955-1964 24% (980 homes), 1965-1972 2% (90 homes), 1973-1982 3% (110 homes), 1983-1992 12% (500 homes), 1993-1999 8% (330 homes) and 2000-2008 3% (130 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.
Knowsley Metropolitan Borough Council also decides for Cherryfield, Halewood North, Prescot North, Whiston and Cronton and Whitefield, so a decision in Roby 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.
Published figures for Roby and Knowsley 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.
| Measure | Roby |
|---|---|
| Dwellings recorded | 4,110 |
| Built pre-1900 | 130 (3%) |
| Built 1900-1918 | 20 (0%) |
| Built 1919-1929 | 30 (1%) |
| Built 1930-1939 | 910 (22%) |
| Built 1945-1954 | 340 (8%) |
| Built 1955-1964 | 980 (24%) |
| Built 1965-1972 | 90 (2%) |
| Built 1973-1982 | 110 (3%) |
| Built 1983-1992 | 500 (12%) |
| Built 1993-1999 | 330 (8%) |
| Built 2000-2008 | 130 (3%) |
| Built before 1919 | 4% |
| Built 1919–1939 | 23% |
| Built 1945–2008 | 60% |
| Conservation areas in Roby | 3 (Roby, St Michaels Church…) |
| Conservation areas district-wide | 15 |
| Article 4 directions recorded | 0 |
| Householder applications decided | 167 |
| Householder applications granted | 95% |
| Decided within 8 weeks | 60% |
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 Knowsley Metropolitan Borough Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
Roby homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from late-1950s and early-1960s houses (24% of 4,110 homes), 1930s semi-detached and detached houses (22%) and 1980s estate houses (12%), 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. Knowsley Metropolitan Borough Council judges every one of them against Knowsley 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. Roby contains Roby, St Michaels Church, The Orchard conservation areas (Roby designated 2015), 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.
Roby also protects whole streets — Roby, St Michaels Church and The Orchard among them. No Article 4 direction is recorded for Knowsley Metropolitan Borough Council, but Roby's 3 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.
Plenty of Roby 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 Knowsley Metropolitan Borough Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Knowsley Metropolitan Borough Council's officers weigh first — and submit a validation-complete pack, whether that is a lawful development certificate, a prior-approval notification or a full householder application.
Below is Knowsley Metropolitan Borough Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Knowsley Metropolitan Borough Council granted 95% of its householder applications in the year to 31 March 2026, and Roby 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.
Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
Across Roby, St Michaels Church and The Orchard, 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-1950s and early-1960s houses (24% of 4,110 homes), a side-return infill frequently pairs with it to square off the plan; on wider 1980s estate houses (12%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.
The 4,110 homes here are 24% 1955-1964, 22% 1930-1939, 12% 1983-1992, 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 Knowsley 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.
We draw extensions on every street in the borough. A few of the neighbourhoods where Roby projects come up most often:
Extension drawings for Roby's conservation area designated in 2015 — footprint-checked, daylight-tested and drawn to Knowsley Metropolitan Borough Council's guidance.
Extension drawings for St Michaels Church's conservation area designated in 2019 — footprint-checked, daylight-tested and drawn to Knowsley Metropolitan Borough Council's guidance.
Extension drawings for The Orchard's conservation area designated in 2014 — footprint-checked, daylight-tested and drawn to Knowsley Metropolitan Borough Council's guidance.
The right extension in Roby 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 type | Permitted development? | What it adds | What Knowsley Metropolitan Borough Council checks |
|---|---|---|---|
| Single-storey rear | Often, within 3m/4m depth (6m/8m via prior approval) | Bigger kitchen-diner across the back | Depth, height, neighbour daylight (45°) |
| Side-return infill | Sometimes, if within width and height limits | Squares off an L-shaped ground floor | Width vs the original house, glazing to boundary |
| Two-storey rear/side | No — full application | Extra bedroom or bathroom above | Bulk, overlooking, 7m rear-boundary gap |
| Wraparound (rear + side) | No — full application | Whole-width open-plan ground floor | Combined footprint and garden retained |
Route depends on your street — conservation areas such as Roby and St Michaels Church and Article 4 directions can remove permitted-development rights.
A fixed process built around how Knowsley Metropolitan Borough Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Roby 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 Knowsley Metropolitan Borough Council decisions.
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.
Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Knowsley Metropolitan Borough Council's extension design guidance.
We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Knowsley Metropolitan Borough Council issues its decision.
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 Roby you will need to apply to Knowsley 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 Roby and St Michaels Church.
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 Knowsley Metropolitan Borough Council and a neighbour-consultation period, and it does not apply on designated land such as Roby's conservation areas. We confirm which route your property qualifies for before drawing.
Two-storey and double-storey extensions almost always need a full householder application to Knowsley 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 Roby address specifically.
A householder planning application in Roby 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. Knowsley Metropolitan Borough Council is the decision-maker.
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 Knowsley Metropolitan Borough Council's building control or an approved inspector can sign the work off. This applies to your Roby address specifically.
Every house and brief is different, so we price each Roby extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Knowsley 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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