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Side return extension plans in Glen — a glazed side-return infill opening up a period kitchen
Glen · Side Return Extension Drawings & Planning

Side return extension plans in Glen

Side-return infill drawings for Glen terraces — the glazed extension that fills the redundant side alley and opens up the kitchen, drawn to Harborough District Council's guidance, delivered in days and revised free until your decision, with a free approval-odds check first.

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What the data says about planning in Glen

Harborough District Council granted 92% of the householder planning decisions it made in its latest published year — 5 points above the 87% England-wide householder average. Glen contains Gaulby, Illston on the Hill, Kings Norton conservation areas (Gaulby designated 1994), 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 postwar (1945–1970) 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 Harborough District Council needs a full application. In conservation areas such as Gaulby, Illston on the Hill and Kings Norton those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Glen is determined against an 8-week statutory target.

Gaulby (conservation area designated in 1994), Illston on the Hill (conservation area designated in 1994), Kings Norton (conservation area designated in 1994), Burton Overy (civil parish within Glen), Gaulby (civil parish within Glen), Great Glen (civil parish within Glen), Illston on the Hill (civil parish within Glen), King's Norton (civil parish within Glen) and Little Stretton (civil parish within Glen) — these are the Glen pockets our drawings cover most. Heritage designations here include Gaulby, Illston on the Hill and Kings Norton. Harborough District Council weighs each proposal against Harborough District Council's development plan and the design policies it applies to householder applications, where the 2,430 homes here are 16% 1965-1972, 12% pre-1900, 9% 1955-1964, 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 steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building, over late-1960s and early-1970s houses (16% of 2,430 homes), Victorian and earlier houses (12%) and late-1950s and early-1960s houses (9%).

Designations, stock and decisions in Glen

Heritage designation is the single biggest variable in Glen, and it is address-specific: Gaulby (conservation area designated in 1994), Illston on the Hill (conservation area designated in 1994) and Kings Norton (conservation area designated in 1994). Inside those boundaries permitted development is curtailed and Harborough District 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, Glen takes in Burton Overy, Gaulby, Great Glen, Illston on the Hill, King's Norton and Little Stretton. No Article 4 direction is recorded for Harborough District Council, but Glen's 3 conservation areas still limit permitted development on those streets.

On stock, Glen is late-1960s and early-1970s houses (16% of 2,430 homes), Victorian and earlier houses (12%) and late-1950s and early-1960s houses (9%) — which is why shallow-pitched roofs and integral garages typical of that period's building and steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building govern what a loft or rear projection can realistically be. Harborough District Council decided 439 householder applications in the latest published year and granted 92%, with 51% issued inside the eight-week target. We work from the council's own published record.

The full build-period split for Glen runs pre-1900 12% (290 homes), 1900-1918 2% (50 homes), 1919-1929 1% (30 homes), 1930-1939 1% (30 homes), 1945-1954 4% (90 homes), 1955-1964 9% (230 homes), 1965-1972 16% (400 homes), 1973-1982 8% (190 homes), 1983-1992 8% (190 homes), 1993-1999 5% (110 homes) and 2000-2008 8% (200 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.

Harborough District Council also decides for Billesdon & Tilton, Bosworth, Dunton, Fleckney, Kibworths, Lubenham, Misterton and Nevill, so a decision in Glen 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 published numbers behind a Glen application

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

MeasureGlen
Dwellings recorded2,430
Built pre-1900290 (12%)
Built 1900-191850 (2%)
Built 1919-192930 (1%)
Built 1930-193930 (1%)
Built 1945-195490 (4%)
Built 1955-1964230 (9%)
Built 1965-1972400 (16%)
Built 1973-1982190 (8%)
Built 1983-1992190 (8%)
Built 1993-1999110 (5%)
Built 2000-2008200 (8%)
Built before 191914%
Built 1919–19392%
Built 1945–200858%
Conservation areas in Glen3 (Gaulby, Illston on the Hill…)
Conservation areas district-wide50
Article 4 directions recorded0
Householder applications decided439
Householder applications granted92%
Decided within 8 weeks51%

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 Harborough District Council's own, from MHCLG live table PS2 for the year to 31 March 2026.

Side returns drawn for Glen's period terraces

The side return is the classic terrace fix, and Glen has the stock for it — the borough is built largely from late-1960s and early-1970s houses (16% of 2,430 homes), Victorian and earlier houses (12%) and late-1950s and early-1960s 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. Harborough District Council judges the infill against Harborough District Council'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. Glen contains Gaulby, Illston on the Hill, Kings Norton conservation areas (Gaulby designated 1994), 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 Glen's terraces sit in conservation areas — Gaulby, Illston on the Hill and Kings Norton among them — where a side extension is no longer permitted development. No Article 4 direction is recorded for Harborough District Council, but Glen's 3 conservation areas still limit permitted development on those streets. We confirm the designation before a line is drawn.

Isometric side return extension drawing for a Glen terrace

Does a side return extension need planning permission in Glen?

Some single-storey side returns in Glen 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 Harborough District Council if any of these apply:

  • The side extension is wider than half the width of the original house
  • It is more than one storey, or higher than 4 metres (or higher than the eaves along the side)
  • The property is on designated land — side extensions are not permitted development in conservation areas
  • You are combining the side return with a rear extension beyond 3 metres, which reads as a wraparound
  • Your terrace is in a conservation area such as Gaulby and Illston on the Hill, where side-extension rights are removed

Glen side return approval rates — live from council data

Below is Harborough District Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Harborough District Council granted 92% of its householder applications in the year to 31 March 2026, and Gaulby 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.

92%householder applications approved in Harborough
87%national average — Harborough is 5 points above the national average

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What side return extensions get approved in Glen

Across Gaulby, Illston on the Hill and Kings Norton, 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 late-1960s and early-1970s houses (16% of 2,430 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 2,430 homes here are 16% 1965-1972, 12% pre-1900, 9% 1955-1964, 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 Harborough District Council sees one coherent scheme rather than two overlapping ones.

Side return extension squaring off the ground floor of a Glen terrace

Side return extensions across Glen

We draw side-return infills on every terraced street in the borough. A few of the neighbourhoods where Glen side returns come up most often:

Gaulby

Side return extension drawings for Gaulby's conservation area designated in 1994 — width-checked, party-wall detailed and drawn to Harborough District Council's guidance.

Illston on the Hill

Side return extension drawings for Illston on the Hill's conservation area designated in 1994 — width-checked, party-wall detailed and drawn to Harborough District Council's guidance.

Kings Norton

Side return extension drawings for Kings Norton's conservation area designated in 1994 — width-checked, party-wall detailed and drawn to Harborough District Council's guidance.

Burton Overy

Side return extension drawings for Burton Overy's civil parish within Glen — width-checked, party-wall detailed and drawn to Harborough District Council's guidance.

Gaulby

Side return extension drawings for Gaulby's civil parish within Glen — width-checked, party-wall detailed and drawn to Harborough District Council's guidance.

Great Glen

Side return extension drawings for Great Glen's civil parish within Glen — width-checked, party-wall detailed and drawn to Harborough District Council's guidance.

Is your Glen side return permitted development or a full application?

Whether a side return in Glen needs permission comes down to width, storeys and whether the street is designated. This is how the cases compare.

Side return typePermitted development?What it gainsWhat Harborough District Council checks
Single-storey infill, within limitsOften yes, if under half the house widthFull-width kitchen-dinerWidth, 4m height, roof glazing
Single-storey, over half widthNo — full applicationWider room, more lightBoundary treatment, neighbour amenity
Two-storey side returnNo — full applicationRoom above as well as belowBulk, overlooking, terrace rhythm
Wraparound (side + rear)No — full applicationL-shaped open-plan ground floorCombined footprint, garden retained

In conservation areas such as Gaulby and Illston on the Hill, side extensions are not permitted development and always need a full application.

Four steps to an approved Glen side return

A fixed process built around how Harborough District Council validates and decides side-return applications — most drawings are submission-ready within seven days of survey.

  1. 1

    Free approval check

    Send us your Glen 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 Harborough District Council decisions.

  2. 2

    Measured survey

    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.

  3. 3

    Side return design & drawings

    Chartered designers develop the infill and its glazed roof to your brief, drawn inside the permitted-development limits or to Harborough District Council's extension guidance, with the boundary and party-wall junction detailed.

  4. 4

    Submission & follow-through

    We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Harborough District Council issues its decision.

Frequently asked questions

Does a side return extension need planning permission in Glen?

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 Glen you will need a full application to Harborough District Council for anything wider or taller, for a two-storey side return, and for any side extension in a conservation area such as Gaulby and Illston on the Hill, where those rights are removed.

What is a side return extension on a Glen terrace?

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. Glen's period terraces are ideally suited to it, which is why the side return is one of the borough's most common extensions. Harborough District Council is the decision-maker.

Do I need a party wall agreement for a side return in Glen?

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 Harborough District Council'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 Glen address specifically.

Can I combine a side return with a rear extension in Glen?

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 Harborough District Council 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 Glen address specifically.

How long does Harborough District Council take to decide a side return application?

A householder planning application in Glen 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. Harborough District Council is the decision-maker.

How much do side return extension plans in Glen cost?

We price each Glen 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 Harborough District Council 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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