Side-return infill drawings for Upwell & Delph terraces — the glazed extension that fills the redundant side alley and opens up the kitchen, drawn to Borough Council of King's Lynn and West Norfolk's guidance, 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. Upwell & Delph contains NORDELPH CONSERVATION AREA, UPWELL CONSERVATION AREA, WIMBOTSHAM CONSERVATION AREA conservation areas (NORDELPH CONSERVATION AREA designated 1978), 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.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. Upwell & Delph carries at least one Article 4 direction, and conservation areas including NORDELPH CONSERVATION AREA, UPWELL CONSERVATION AREA and WIMBOTSHAM CONSERVATION AREA remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Upwell & Delph is determined against an 8-week statutory target.
NORDELPH (conservation area designated in 1978), UPWELL (conservation area designated in 1977), WIMBOTSHAM (conservation area designated in 1979), Nordelph (civil parish within Upwell & Delph), Stow Bardolph (civil parish within Upwell & Delph), Upwell (civil parish within Upwell & Delph), Welney (civil parish within Upwell & Delph), Wimbotsham (civil parish within Upwell & Delph) and Downham West (civil parish within Upwell & Delph) — these are the Upwell & Delph pockets our drawings cover most. Heritage designations here include NORDELPH CONSERVATION AREA, UPWELL CONSERVATION AREA and WIMBOTSHAM CONSERVATION AREA. Borough Council of King's Lynn and West Norfolk weighs each proposal against Borough Council of King's Lynn and West Norfolk's development plan and the design policies it applies to householder applications, where the 2,360 homes here are 17% pre-1900, 11% 2000-2008, 9% 1900-1918, which is what sets the realistic roof and rear-projection options. On roofs the borough is steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and trussed-rafter roofs typical of 2000s building, over Victorian and earlier houses (17% of 2,360 homes), 2000s houses and apartments (11%) and Edwardian houses (9%).
Before anything is drawn we check your address against the designations that apply in Upwell & Delph: NORDELPH (conservation area designated in 1978), UPWELL (conservation area designated in 1977) and WIMBOTSHAM (conservation area designated in 1979). 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, Upwell & Delph takes in Nordelph, Stow Bardolph, Upwell, Welney, Wimbotsham and Downham West. Borough Council of King's Lynn and West Norfolk has 12 recorded Article 4 directions — check the address before assuming PD applies in Upwell & Delph.
On stock, Upwell & Delph is Victorian and earlier houses (17% of 2,360 homes), 2000s houses and apartments (11%) and Edwardian houses (9%) — which is why steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and trussed-rafter roofs typical of 2000s 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. That decision record, not a national figure, is what we design to.
The full build-period split for Upwell & Delph runs pre-1900 17% (400 homes), 1900-1918 9% (220 homes), 1919-1929 4% (100 homes), 1930-1939 6% (150 homes), 1945-1954 8% (200 homes), 1955-1964 6% (150 homes), 1965-1972 4% (100 homes), 1973-1982 6% (130 homes), 1983-1992 5% (120 homes), 1993-1999 5% (120 homes) and 2000-2008 11% (260 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, Downham Old Town, Feltwell, Heacham and Methwold, so a decision in Upwell & Delph 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 Upwell & Delph 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 | Upwell & Delph |
|---|---|
| Dwellings recorded | 2,360 |
| Built pre-1900 | 400 (17%) |
| Built 1900-1918 | 220 (9%) |
| Built 1919-1929 | 100 (4%) |
| Built 1930-1939 | 150 (6%) |
| Built 1945-1954 | 200 (8%) |
| Built 1955-1964 | 150 (6%) |
| Built 1965-1972 | 100 (4%) |
| Built 1973-1982 | 130 (6%) |
| Built 1983-1992 | 120 (5%) |
| Built 1993-1999 | 120 (5%) |
| Built 2000-2008 | 260 (11%) |
| Built before 1919 | 26% |
| Built 1919–1939 | 11% |
| Built 1945–2008 | 46% |
| Conservation areas in Upwell & Delph | 3 (NORDELPH CONSERVATION AREA, UPWELL 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 side return is the classic terrace fix, and Upwell & Delph has the stock for it — the borough is built largely from Victorian and earlier houses (17% of 2,360 homes), 2000s houses and apartments (11%) and Edwardian houses (9%), and the Victorian and Edwardian versions almost all have an L-shaped back addition with a wasted alley beside it. Fill that alley and the dark galley kitchen becomes a bright, square room the full width of the house. Borough Council of King's Lynn and West Norfolk judges the infill against Borough Council of King's Lynn and West Norfolk's development plan and the design policies it applies to householder applications, and because it runs along the party boundary, the neighbour relationship is read before the design.
That boundary is where the drawings earn their keep. We set the infill wall on or up to the line, keep the roof — usually a glazed lantern or a shallow pitch tying into the existing back-addition slope — below the neighbour's first-floor windows, and detail the rainwater and party-wall junction so the build is watertight and the Party Wall Act is satisfied. Upwell & Delph contains NORDELPH CONSERVATION AREA, UPWELL CONSERVATION AREA, WIMBOTSHAM CONSERVATION AREA conservation areas (NORDELPH CONSERVATION AREA designated 1978), so materials, fenestration and roof form are assessed against the appraisal, so we resolve it on the section rather than leave it to the case officer.
Many of Upwell & Delph's terraces sit in conservation areas — NORDELPH CONSERVATION AREA, UPWELL CONSERVATION AREA and WIMBOTSHAM CONSERVATION AREA among them — where a side extension is no longer permitted development. Borough Council of King's Lynn and West Norfolk has 12 recorded Article 4 directions — check the address before assuming PD applies in Upwell & Delph. We confirm the designation before a line is drawn.
Some single-storey side returns in Upwell & Delph are permitted development, but the width and boundary make an application more likely than for a straight rear extension. You will normally need to apply to Borough Council of King's Lynn and West Norfolk if any of these apply:
We draw the infill wall on the boundary, the glazed roof below the neighbour's windows and the party-wall junction on the page — the details Borough Council of King's Lynn and West Norfolk's officers and your neighbour both check — and submit a validation-complete pack, whether that is a lawful development certificate or a full householder application.
Below is Borough Council of King's Lynn and West Norfolk's real householder decision record, drawn 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 NORDELPH CONSERVATION AREA shapes what is approved here. Side returns hinge on width, roof glazing and the party boundary, so a pack that resolves those details 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 NORDELPH, UPWELL and WIMBOTSHAM, the approved side return is a single-storey infill roofed with a glazed lantern or roof light to pull daylight deep into the plan, its flank wall built on the boundary and finished to match the host brick. On the borough's victorian and earlier houses (17% of 2,360 homes), this is frequently the single biggest gain in usable ground-floor space, and where it stays within the width and height limits it can proceed under permitted development or a lawful development certificate.
The 2,360 homes here are 17% pre-1900, 11% 2000-2008, 9% 1900-1918, which is what sets the realistic roof and rear-projection options. We keep the glazed roof below the neighbour's cill line, set the gutter and the party-wall flashing so water and maintenance are designed in, and — where owners want the full open-plan room — pair the infill with a rear extension as a single wraparound application. That way Borough Council of King's Lynn and West Norfolk sees one coherent scheme rather than two overlapping ones.
We draw side-return infills on every terraced street in the borough. A few of the neighbourhoods where Upwell & Delph side returns come up most often:
Side return extension drawings for NORDELPH's conservation area designated in 1978 — width-checked, party-wall detailed and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Side return extension drawings for UPWELL's conservation area designated in 1977 — width-checked, party-wall detailed and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Side return extension drawings for WIMBOTSHAM's conservation area designated in 1979 — width-checked, party-wall detailed and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Side return extension drawings for Nordelph's civil parish within Upwell & Delph — width-checked, party-wall detailed and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Side return extension drawings for Stow Bardolph's civil parish within Upwell & Delph — width-checked, party-wall detailed and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Side return extension drawings for Upwell's civil parish within Upwell & Delph — width-checked, party-wall detailed and drawn to Borough Council of King's Lynn and West Norfolk's guidance.
Whether a side return in Upwell & Delph needs permission comes down to width, storeys and whether the street is designated. This is how the cases compare.
| Side return type | Permitted development? | What it gains | What Borough Council of King's Lynn and West Norfolk checks |
|---|---|---|---|
| Single-storey infill, within limits | Often yes, if under half the house width | Full-width kitchen-diner | Width, 4m height, roof glazing |
| Single-storey, over half width | No — full application | Wider room, more light | Boundary treatment, neighbour amenity |
| Two-storey side return | No — full application | Room above as well as below | Bulk, overlooking, terrace rhythm |
| Wraparound (side + rear) | No — full application | L-shaped open-plan ground floor | Combined footprint, garden retained |
In conservation areas such as NORDELPH CONSERVATION AREA and UPWELL CONSERVATION AREA, side extensions are not permitted development and always need a full application.
A fixed process built around how Borough Council of King's Lynn and West Norfolk validates and decides side-return applications — most drawings are submission-ready within seven days of survey.
Send us your Upwell & Delph postcode and terrace type. We confirm your conservation and Article 4 status, whether the infill stays within the side-extension width limit, and score your odds against live Borough Council of King's Lynn and West Norfolk decisions.
We measure the side alley, the back-addition wall, floor and eaves levels and the neighbour's window heights — the numbers the width limit, roof pitch and party-wall detailing depend on.
Chartered designers develop the infill and its glazed roof to your brief, drawn inside the permitted-development limits or to Borough Council of King's Lynn and West Norfolk's extension guidance, with the boundary and party-wall junction detailed.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Borough Council of King's Lynn and West Norfolk issues its decision.
Sometimes not. A single-storey side-return infill can be permitted development if it is no wider than half the original house, no higher than 4 metres, and the property is not on designated land. In Upwell & Delph you will need a full application to Borough Council of King's Lynn and West Norfolk for anything wider or taller, for a two-storey side return, and for any side extension in a conservation area such as NORDELPH CONSERVATION AREA and UPWELL CONSERVATION AREA, where those rights are removed.
It is an infill that fills the narrow open alley running alongside the rear back-addition of a Victorian or Edwardian terrace — the strip of ground that is usually too small to use. Building over it squares off the ground floor, so a cramped galley kitchen becomes a full-width room. Upwell & Delph's period terraces are ideally suited to it, which is why the side return is one of the borough's most common extensions. Borough Council of King's Lynn and West Norfolk is the decision-maker.
Almost always. A side return is built on or up to the boundary with your neighbour, so the Party Wall etc. Act applies and you must serve notice before work starts — this is entirely separate from Borough Council of King's Lynn and West Norfolk's planning decision. We detail the party-wall junction on the drawings and flag the notice early so a surveyor can be appointed without delaying the build. This applies to your Upwell & Delph address specifically.
Yes, and it is common — the combined L-shape is a wraparound extension. Once the side infill joins a rear projection beyond the permitted-development depth, the whole thing needs a full householder application to Borough Council of King's Lynn and West Norfolk rather than qualifying as permitted development. We draw it as one coherent scheme so the council assesses a single footprint, which reads more clearly than two overlapping proposals. This applies to your Upwell & Delph address specifically.
A householder planning application in Upwell & Delph runs to a statutory eight-week target, and a lawful development certificate to eight weeks as well, though an incomplete pack can stall at validation. Because a side return involves the boundary and roof glazing, a complete, well-detailed submission matters — we prepare it validation-complete and manage officer queries to keep the decision on track. Borough Council of King's Lynn and West Norfolk is the decision-maker.
We price each Upwell & Delph side return individually, because alley width and roof form vary house to house, 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 infill is permitted development or needs an application. Call 020 7864 7245 to start.
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