Back-of-house extension drawings for Millbay homes — the glazed kitchen-diner across the rear, drawn to Plymouth City Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Plymouth City Council granted 93% of the householder planning decisions it made in its latest published year — 6 points above the 87% England-wide householder average. Millbay is a major regeneration area, so new waterfront development is weighed against the surviving Union Street Victorian frontages and the two conservation areas that flank it, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901) housing stock sets the design brief on most streets.
Class A and Class B set the thresholds — a rear dormer to 40m³ on a terrace or 50m³ on a semi or detached, and a single-storey rear extension to 3m on a terrace or 4m on a detached house — beyond which Plymouth City Council needs a full application. Millbay carries at least one Article 4 direction, and conservation areas including Union Street, Stonehouse Peninsula and The Hoe remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Millbay is determined against an 8-week statutory target.
Union Street (the Victorian boulevard laid out to link Plymouth and Devonport, now a conservation area), Millbay Docks (the working ferry port fringed by regeneration-era apartments), West Hoe (Victorian terraces on the limestone slope between Millbay and the Hoe), Bath Street (surviving Victorian streets behind the dock frontage), Rendle Street (close-grained terraces off Union Street) and Stonehouse fringe (the western edge running into the Stonehouse Peninsula) — these are the Millbay pockets our drawings cover most. Heritage designations here include Union Street, Stonehouse Peninsula and The Hoe. Plymouth City Council weighs each proposal against the Plymouth and South West Devon Joint Local Plan (2019), where Union Street's historic role as the ceremonial link between Plymouth and Devonport gives its terraced and commercial frontages protected townscape value. Much of Millbay is already flats — both converted period stock and new-build apartments — which hold no householder permitted-development rights of their own.. On roofs the borough is pitched and parapet roofs on the Victorian terraces and flat and mansard roofs on the newer apartment blocks, over Victorian commercial and terraced frontages along Union Street, new-build waterfront apartment blocks around the docks and converted flats in the surviving period stock.
The rear extension is the workhorse of Millbay home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from Victorian commercial and terraced frontages along Union Street, new-build waterfront apartment blocks around the docks and converted flats in the surviving period stock, most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Plymouth City Council scrutinises. The council reads the proposal against the Plymouth and South West Devon Joint Local Plan (2019), and the first line an officer draws is the 45-degree splay from the neighbour's nearest window.
So the drawings live or die on geometry. We set the depth against the exact permitted-development figure, hold the eaves and the flat-roof or lantern build-up under the 4-metre height ceiling, and show the projection tested against both the 45-degree plan angle and the 25-degree section angle to the neighbouring windows. Millbay is a major regeneration area, so new waterfront development is weighed against the surviving Union Street Victorian frontages and the two conservation areas that flank it, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — Union Street, Stonehouse Peninsula and The Hoe among Millbay's — the larger-home extension route is switched off and even a modest rear addition needs consent. Millbay adjoins the city-centre streets within Plymouth's HMO Article 4 direction (in force 14 September 2012), which removed the permitted-development right to form a small house in multiple occupation, so a shared-house conversion on this edge needs planning permission. We confirm the designation before the survey.
Many single-storey rear extensions in Millbay are permitted development and need no application. You will normally need to apply to Plymouth City Council, or use the larger-home prior-approval route, if any of these apply:
We draw the depth, the roof build-up and the daylight splays to each neighbour on the page — the tests Plymouth City Council's officers apply first — and submit a validation-complete pack, whether that is a lawful development certificate, a larger-home prior-approval notice or a full householder application.
Below is Plymouth City Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Plymouth consents the large majority of householder applications around Millbay, where the regeneration context and the Union Street, Stonehouse Peninsula and Hoe conservation areas make townscape and waterfront-setting impact the deciding factors. Rear extensions turn most often on neighbour daylight and depth, so a drawing pack that proves those tests upfront is decided faster and refused less often than a DIY submission.
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 Union Street, Millbay Docks and West Hoe, the approved rear extension is typically a single-storey glazed box within the depth limit, roofed either flat with a lantern or in a shallow mono-pitch, and finished in brick or render to match the host wall. On the borough's victorian commercial and terraced frontages along union street, keeping the projection to the permitted-development figure often avoids an application entirely; where owners want the full 6 metres, the larger-home route succeeds when the neighbour-consultation period passes without a sustained objection.
Union Street's historic role as the ceremonial link between Plymouth and Devonport gives its terraced and commercial frontages protected townscape value. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Plymouth City Council expects — so the back elevation answers the amenity case before a neighbour can lodge one. Two-storey rear extensions we draw with the 7-metre boundary gap and privacy screening resolved on the plan.
We draw rear extensions on every street in the borough. A few of the neighbourhoods where Millbay back-of-house projects come up most often:
Rear extension drawings for Union Street's the Victorian boulevard laid out to link Plymouth and Devonport, now a conservation area — depth-checked, daylight-tested and drawn to Plymouth City Council's guidance.
Rear extension drawings for Millbay Docks's the working ferry port fringed by regeneration-era apartments — depth-checked, daylight-tested and drawn to Plymouth City Council's guidance.
Rear extension drawings for West Hoe's Victorian terraces on the limestone slope between Millbay and the Hoe — depth-checked, daylight-tested and drawn to Plymouth City Council's guidance.
Rear extension drawings for Bath Street's surviving Victorian streets behind the dock frontage — depth-checked, daylight-tested and drawn to Plymouth City Council's guidance.
Rear extension drawings for Rendle Street's close-grained terraces off Union Street — depth-checked, daylight-tested and drawn to Plymouth City Council's guidance.
Rear extension drawings for Stonehouse fringe's the western edge running into the Stonehouse Peninsula — depth-checked, daylight-tested and drawn to Plymouth City Council's guidance.
How far you can extend at the back in Millbay depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Plymouth City Council checks |
|---|---|---|---|
| Standard permitted development | 3m terrace/semi · 4m detached | Lawful development certificate (optional) | Depth, 4m height, materials |
| Larger-home prior approval | 6m terrace/semi · 8m detached | Prior-approval notice + neighbour consultation | Neighbour objections on amenity |
| Full householder application | Beyond the above, or two-storey | Full planning permission | Daylight (45°/25°), bulk, garden retained |
| Conservation area | Case by case | Full planning permission | Character, roof form, boundary treatment |
The larger-home route is switched off on designated land — conservation areas such as Union Street and Stonehouse Peninsula and Article 4 streets need a full application.
A fixed process built around how Plymouth City Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Millbay postcode and house type. We confirm your conservation and Article 4 status, how much rear-extension depth you have under permitted development, and score your odds against live Plymouth City Council decisions.
We measure the original rear wall, floor and eaves levels, side and rear boundary distances and the neighbours' window positions — the numbers the depth limit and daylight splays depend on.
Chartered designers develop the single or two-storey rear extension to your brief, drawn inside the permitted-development limits or to Plymouth City Council's extension design guidance, with the daylight angles shown.
We submit the certificate, prior-approval notice or application, handle validation and case-officer queries, and revise the drawings free until Plymouth City Council issues its decision.
Often not. 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 Millbay. You will need to involve Plymouth City Council for anything deeper via the larger-home route, for two-storey rear extensions, and for any rear extension in a conservation area such as Union Street and Stonehouse Peninsula, where those permitted-development rights fall away.
The larger-home extension scheme lets a single-storey rear extension reach 6 metres on a terrace or semi, or 8 metres on a detached house — double the standard allowance. It is not automatic: you submit a prior-approval notification to Plymouth City Council, neighbours are consulted, and if one objects on amenity grounds the council rules on it. It also does not apply on designated land such as Millbay's conservation areas.
It is the daylight test Plymouth City Council applies to protect neighbours. Drawn on plan, a line at 45 degrees from the midpoint of the neighbour's nearest ground-floor window should not be crossed by your extension; a companion 25-degree line is checked in section. If the projection breaches it, the extension is likely to be shortened or refused, so we test and prove it on the drawings before submission. This applies to your Millbay address specifically.
A two-storey rear extension almost always needs a full householder application to Plymouth City Council, as it sits outside permitted development on most homes. The council checks that it stays at least 7 metres from the rear boundary, does not overbear the neighbours and avoids new overlooking. We resolve the boundary gap, privacy and daylight on the plans so the application is decided on its merits. This applies to your Millbay address specifically.
Frequently, yes. If the rear extension involves work to a shared wall, building up to the boundary, or excavating foundations near a neighbour's structure, the Party Wall etc. Act applies and you must serve notice — this is separate from Plymouth City Council's planning decision. We flag it early and can prepare the drawings a party-wall surveyor needs alongside the planning set. This applies to your Millbay address specifically.
We price each Millbay rear extension on its own footprint and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Plymouth City Council approves, and we confirm at the outset whether your extension is permitted development, needs prior approval, or a full application. Call 020 7864 7245 to begin.
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