Back-of-house extension drawings for Downham Old Town homes — the glazed kitchen-diner across the rear, drawn to Borough Council of King's Lynn and West Norfolk's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Borough Council of King's Lynn and West Norfolk granted 95% of the householder planning decisions it made in its latest published year — 8 points above the 87% England-wide householder average. Downham Old Town contains the DOWNHAM MARKET CONSERVATION AREA conservation area (DOWNHAM MARKET CONSERVATION AREA designated 1975), so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901) and Edwardian (1901–1910) housing stock sets the design brief on most streets.
Before permission is required, Class B allows 40m³ of added loft volume on a terrace and 50m³ on a semi or detached house, and Class A allows a 3m single-storey rear extension on a terrace or 4m on a detached house. Downham Old Town carries at least one Article 4 direction, and conservation areas including DOWNHAM MARKET CONSERVATION AREA remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Downham Old Town is determined against an 8-week statutory target.
DOWNHAM MARKET (conservation area designated in 1975) and Downham Market (civil parish within Downham Old Town) — these are the Downham Old Town pockets our drawings cover most. Heritage designations here include DOWNHAM MARKET CONSERVATION AREA. Borough Council of King's Lynn and West Norfolk weighs each proposal against the adopted Borough Council of King's Lynn and West Norfolk local plan and Borough Council of King's Lynn and West Norfolk's design guidance for householder work, where the 1,550 homes here are 14% 2000-2008, 13% 1900-1918, 12% pre-1900, which is what sets the realistic roof and rear-projection options. On roofs the borough is trussed-rafter roofs typical of 2000s building and pitched and hipped roofs with generous eaves typical of Edwardian building, over 2000s houses and apartments (14% of 1,550 homes), Edwardian houses (13%) and Victorian and earlier houses (12%).
What is permitted in Downham Old Town turns on designation first, so that is where we start: DOWNHAM MARKET (conservation area designated in 1975). Inside those boundaries permitted development is curtailed and Borough Council of King's Lynn and West Norfolk 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, Downham Old Town takes in Downham Market. Borough Council of King's Lynn and West Norfolk has 12 recorded Article 4 directions — check the address before assuming PD applies in Downham Old Town.
On stock, Downham Old Town is 2000s houses and apartments (14% of 1,550 homes), Edwardian houses (13%) and Victorian and earlier houses (12%) — which is why trussed-rafter roofs typical of 2000s building and pitched and hipped roofs with generous eaves typical of Edwardian building govern what a loft or rear projection can realistically be. Borough Council of King's Lynn and West Norfolk decided 521 householder applications in the latest published year and granted 95%, with 87% issued inside the eight-week target. We draw to that record rather than to a national average.
The full build-period split for Downham Old Town runs pre-1900 12% (180 homes), 1900-1918 13% (200 homes), 1919-1929 3% (50 homes), 1930-1939 3% (50 homes), 1945-1954 4% (60 homes), 1955-1964 8% (130 homes), 1965-1972 6% (90 homes), 1973-1982 6% (100 homes), 1983-1992 5% (70 homes), 1993-1999 5% (70 homes) and 2000-2008 14% (220 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.
Borough Council of King's Lynn and West Norfolk also decides for Airfield, Bircham with Rudhams, Brancaster, Dersingham, Feltwell, Heacham, Methwold and Terrington, so a decision in Downham Old Town 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.
The Article 4 directions recorded for this council include Coastal area Heacham, Coastal area Snettisham, Holme next the Sea and Kings Lynn Conservation Area. Each removes a specific permitted-development right inside its own boundary, which is why the check is done on the address rather than on the town.
Published figures for Downham Old Town and Borough Council of King's Lynn and West Norfolk. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Downham Old Town |
|---|---|
| Dwellings recorded | 1,550 |
| Built pre-1900 | 180 (12%) |
| Built 1900-1918 | 200 (13%) |
| Built 1919-1929 | 50 (3%) |
| Built 1930-1939 | 50 (3%) |
| Built 1945-1954 | 60 (4%) |
| Built 1955-1964 | 130 (8%) |
| Built 1965-1972 | 90 (6%) |
| Built 1973-1982 | 100 (6%) |
| Built 1983-1992 | 70 (5%) |
| Built 1993-1999 | 70 (5%) |
| Built 2000-2008 | 220 (14%) |
| Built before 1919 | 25% |
| Built 1919–1939 | 6% |
| Built 1945–2008 | 48% |
| Conservation areas in Downham Old Town | 1 (DOWNHAM MARKET CONSERVATION AREA) |
| Conservation areas district-wide | 44 |
| Article 4 directions recorded | 12 |
| Householder applications decided | 521 |
| Householder applications granted | 95% |
| Decided within 8 weeks | 87% |
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 Borough Council of King's Lynn and West Norfolk's own, from MHCLG live table PS2 for the year to 31 March 2026.
The rear extension is the workhorse of Downham Old Town home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from 2000s houses and apartments (14% of 1,550 homes), Edwardian houses (13%) and Victorian and earlier houses (12%), most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Borough Council of King's Lynn and West Norfolk scrutinises. The council reads the proposal against the adopted Borough Council of King's Lynn and West Norfolk local plan and Borough Council of King's Lynn and West Norfolk's design guidance for householder work, 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. Downham Old Town contains the DOWNHAM MARKET CONSERVATION AREA conservation area (DOWNHAM MARKET CONSERVATION AREA designated 1975), so materials, fenestration and roof form are assessed against the appraisal, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — DOWNHAM MARKET CONSERVATION AREA among Downham Old Town's — the larger-home extension route is switched off and even a modest rear addition needs consent. Borough Council of King's Lynn and West Norfolk has 12 recorded Article 4 directions — check the address before assuming PD applies in Downham Old Town. We confirm the designation before the survey.
Many single-storey rear extensions in Downham Old Town are permitted development and need no application. You will normally need to apply to Borough Council of King's Lynn and West Norfolk, 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 Borough Council of King's Lynn and West Norfolk'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 Borough Council of King's Lynn and West Norfolk's real householder decision record, taken from official planning statistics and refreshed as new data lands. Borough Council of King's Lynn and West Norfolk granted 95% of its householder applications in the year to 31 March 2026, and DOWNHAM MARKET CONSERVATION AREA shapes what is approved here. 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 DOWNHAM MARKET and Downham Market, 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 2000s houses and apartments (14% of 1,550 homes), 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.
The 1,550 homes here are 14% 2000-2008, 13% 1900-1918, 12% pre-1900, which is what sets the realistic roof and rear-projection options. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Borough Council of King's Lynn and West Norfolk 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 Downham Old Town back-of-house projects come up most often:
Rear extension drawings for DOWNHAM MARKET's conservation area designated in 1975 — depth-checked, daylight-tested and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Rear extension drawings for Downham Market's civil parish within Downham Old Town — depth-checked, daylight-tested and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
How far you can extend at the back in Downham Old Town depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Borough Council of King's Lynn and West Norfolk 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 DOWNHAM MARKET CONSERVATION AREA and Article 4 streets need a full application.
A fixed process built around how Borough Council of King's Lynn and West Norfolk validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Downham Old Town 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 Borough Council of King's Lynn and West Norfolk 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 Borough Council of King's Lynn and West Norfolk'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 Borough Council of King's Lynn and West Norfolk 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 Downham Old Town. You will need to involve Borough Council of King's Lynn and West Norfolk for anything deeper via the larger-home route, for two-storey rear extensions, and for any rear extension in a conservation area such as DOWNHAM MARKET CONSERVATION AREA, 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 Borough Council of King's Lynn and West Norfolk, 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 Downham Old Town's conservation areas.
It is the daylight test Borough Council of King's Lynn and West Norfolk 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 Downham Old Town address specifically.
A two-storey rear extension almost always needs a full householder application to Borough Council of King's Lynn and West Norfolk, 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 Downham Old Town 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 Borough Council of King's Lynn and West Norfolk'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 Downham Old Town address specifically.
We price each Downham Old Town 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 Borough Council of King's Lynn and West Norfolk 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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