MCIAT chartered drawings · Fixed fees across all 33 London boroughs
Services
Areas
Guides
ProcessOur promiseFAQ
Free approval reportGet my free quote020 7864 7245
House extension plans in Mid Test — a glazed single-storey rear extension on a period home
Mid Test · House Extension Drawings & Planning

House extension plans in Mid Test

Single-storey, double-storey, rear and side extension drawings for Mid Test homes — measured to Test Valley Borough Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.

★★★★★ Rated 4.9/5 by London homeowners96% approval rate · 2,400+ drawings delivered
Share

Mid Test planning decisions and design rules

Test Valley Borough Council granted 96% of the householder planning decisions it made in its latest published year — 9 points above the 87% England-wide householder average. Mid Test contains Broughton, Houghton and Bossington, Kings Somborne conservation areas (Broughton designated 1971), 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.

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. In conservation areas such as Broughton, Houghton and Bossington and Kings Somborne those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Mid Test is determined against an 8-week statutory target.

Broughton (conservation area designated in 1971), Houghton and Bossington (conservation area designated in 1990), Kings Somborne (conservation area designated in 1969), Leckford (conservation area designated in 1989), Longstock (conservation area designated in 1989), Mottisfont (conservation area designated in 1987), Nether, Over and Middle Wallop (conservation area designated in 1980), Stockbridge (conservation area designated in 1971), WEST DEAN (conservation area designated in 1990), West Tytherley (conservation area designated in 1991), East Dean (civil parish within Mid Test), East Tytherley (civil parish within Mid Test), Frenchmoor (civil parish within Mid Test), Houghton (civil parish within Mid Test), Kings Somborne (civil parish within Mid Test) and Leckford (civil parish within Mid Test) — these are the Mid Test pockets our drawings cover most. Heritage designations here include Broughton, Houghton and Bossington, Kings Somborne, Leckford, Longstock, Mottisfont, Nether, Over and Middle Wallop, Stockbridge, WEST DEAN and West Tytherley. Test Valley Borough Council weighs each proposal against Test Valley Borough Council's adopted local plan and its householder design guidance, where the 3,950 homes here are 27% pre-1900, 11% 2000-2008, 7% 1955-1964, 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 (27% of 3,950 homes), 2000s houses and apartments (11%) and late-1950s and early-1960s houses (7%).

Why a Mid Test scheme is judged on Mid Test terms

What is permitted in Mid Test turns on designation first, so that is where we start: Broughton (conservation area designated in 1971), Houghton and Bossington (conservation area designated in 1990), Kings Somborne (conservation area designated in 1969), Leckford (conservation area designated in 1989), Longstock (conservation area designated in 1989), Mottisfont (conservation area designated in 1987), Nether, Over and Middle Wallop (conservation area designated in 1980), Stockbridge (conservation area designated in 1971), WEST DEAN (conservation area designated in 1990) and West Tytherley (conservation area designated in 1991). Inside those boundaries permitted development is curtailed and Test Valley 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.

Beyond the designated areas, Mid Test takes in East Dean, East Tytherley, Frenchmoor, Houghton, Kings Somborne and Leckford. No Article 4 direction is recorded for Test Valley Borough Council, but Mid Test's 10 conservation areas still limit permitted development on those streets.

On stock, Mid Test is Victorian and earlier houses (27% of 3,950 homes), 2000s houses and apartments (11%) and late-1950s and early-1960s houses (7%) — 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. Test Valley Borough Council decided 533 householder applications in the latest published year and granted 96%, with 76% issued inside the eight-week target. We draw to that record rather than to a national average.

The full build-period split for Mid Test runs pre-1900 27% (1,060 homes), 1900-1918 4% (160 homes), 1919-1929 3% (110 homes), 1930-1939 6% (230 homes), 1945-1954 7% (270 homes), 1955-1964 7% (280 homes), 1965-1972 7% (280 homes), 1973-1982 7% (270 homes), 1983-1992 6% (240 homes), 1993-1999 4% (140 homes) and 2000-2008 11% (430 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.

Test Valley Borough Council also decides for Blackwater, Harewood, Ampfield & Braishfield, Anna, Bellinger, Bourne Valley and Charlton & the Pentons, so a decision in Mid Test 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.

Mid Test by the published data

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

MeasureMid Test
Dwellings recorded3,950
Built pre-19001,060 (27%)
Built 1900-1918160 (4%)
Built 1919-1929110 (3%)
Built 1930-1939230 (6%)
Built 1945-1954270 (7%)
Built 1955-1964280 (7%)
Built 1965-1972280 (7%)
Built 1973-1982270 (7%)
Built 1983-1992240 (6%)
Built 1993-1999140 (4%)
Built 2000-2008430 (11%)
Built before 191931%
Built 1919–19399%
Built 1945–200848%
Conservation areas in Mid Test10 (Broughton, Houghton and Bossington…)
Conservation areas district-wide36
Article 4 directions recorded0
Householder applications decided533
Householder applications granted96%
Decided within 8 weeks76%

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 Test Valley Borough Council's own, from MHCLG live table PS2 for the year to 31 March 2026.

Extension plans built around Test Valley Borough Council's rules

Mid Test homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from Victorian and earlier houses (27% of 3,950 homes), 2000s houses and apartments (11%) and late-1950s and early-1960s houses (7%), 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. Test Valley Borough Council judges every one of them against Test Valley 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. Mid Test contains Broughton, Houghton and Bossington, Kings Somborne conservation areas (Broughton designated 1971), 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.

Mid Test also protects whole streets — Broughton, Houghton and Bossington, Kings Somborne, Leckford, Longstock, Mottisfont, Nether, Over and Middle Wallop, Stockbridge, WEST DEAN and West Tytherley among them. No Article 4 direction is recorded for Test Valley Borough Council, but Mid Test's 10 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.

Isometric house extension drawing for a Mid Test home

Do I need planning permission to extend my house in Mid Test?

Plenty of Mid Test 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 Test Valley Borough Council if any of these apply:

  • The single-storey rear extension is deeper than 3 metres on a terrace or semi, or 4 metres on a detached house (6m/8m needs prior approval under the larger-home scheme)
  • It is a two-storey or double-storey extension, or the rear extension is higher than 4 metres
  • A side extension is wider than half the original house, or more than one storey
  • Any part projects forward of the principal (front) elevation, or the extension covers more than half the garden
  • Your home is in a conservation area such as Broughton and Houghton and Bossington, where the larger-home route and side extensions are not permitted development

Mid Test extension approval rates — live from council data

Below is Test Valley Borough Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Test Valley Borough Council granted 96% of its householder applications in the year to 31 March 2026, and Broughton 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.

96%householder applications approved in Test Valley
87%national average — Test Valley is 9 points above the national average

Ready for drawings your council will approve?

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.

Get your free fixed quote

60 seconds now. A fixed, no-obligation quote back within one working day — and we'll tell you if you don't even need planning.

No obligation · No spam · Reply within 1 working day

Which extensions get approved in Mid Test

Across Broughton, Houghton and Bossington and Kings Somborne, 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 victorian and earlier houses (27% of 3,950 homes), a side-return infill frequently pairs with it to square off the plan; on wider late-1950s and early-1960s houses (7%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.

The 3,950 homes here are 27% pre-1900, 11% 2000-2008, 7% 1955-1964, 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 Test Valley 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.

Single-storey rear extension opening onto the garden of a Mid Test house

House extensions across Mid Test

We draw extensions on every street in the borough. A few of the neighbourhoods where Mid Test projects come up most often:

Broughton

Extension drawings for Broughton's conservation area designated in 1971 — footprint-checked, daylight-tested and drawn to Test Valley Borough Council's guidance.

Houghton and Bossington

Extension drawings for Houghton and Bossington's conservation area designated in 1990 — footprint-checked, daylight-tested and drawn to Test Valley Borough Council's guidance.

Kings Somborne

Extension drawings for Kings Somborne's conservation area designated in 1969 — footprint-checked, daylight-tested and drawn to Test Valley Borough Council's guidance.

Leckford

Extension drawings for Leckford's conservation area designated in 1989 — footprint-checked, daylight-tested and drawn to Test Valley Borough Council's guidance.

Longstock

Extension drawings for Longstock's conservation area designated in 1989 — footprint-checked, daylight-tested and drawn to Test Valley Borough Council's guidance.

Mottisfont

Extension drawings for Mottisfont's conservation area designated in 1987 — footprint-checked, daylight-tested and drawn to Test Valley Borough Council's guidance.

Which extension suits your Mid Test home?

The right extension in Mid Test 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 typePermitted development?What it addsWhat Test Valley Borough Council checks
Single-storey rearOften, within 3m/4m depth (6m/8m via prior approval)Bigger kitchen-diner across the backDepth, height, neighbour daylight (45°)
Side-return infillSometimes, if within width and height limitsSquares off an L-shaped ground floorWidth vs the original house, glazing to boundary
Two-storey rear/sideNo — full applicationExtra bedroom or bathroom aboveBulk, overlooking, 7m rear-boundary gap
Wraparound (rear + side)No — full applicationWhole-width open-plan ground floorCombined footprint and garden retained

Route depends on your street — conservation areas such as Broughton and Houghton and Bossington and Article 4 directions can remove permitted-development rights.

Four steps to an approved Mid Test extension

A fixed process built around how Test Valley Borough Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.

  1. 1

    Free approval check

    Tell us your Mid Test 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 Test Valley Borough Council decisions.

  2. 2

    Measured survey

    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.

  3. 3

    Extension design & drawings

    Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Test Valley Borough Council's extension design guidance.

  4. 4

    Submission & follow-through

    We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Test Valley Borough Council issues its decision.

Frequently asked questions

Do I need planning permission to extend my house in Mid Test?

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 Mid Test you will need to apply to Test Valley 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 Broughton and Houghton and Bossington.

How deep can a single-storey rear extension go in Mid Test without planning permission?

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 Test Valley Borough Council and a neighbour-consultation period, and it does not apply on designated land such as Mid Test's conservation areas. We confirm which route your property qualifies for before drawing.

Can I build a double-storey extension in Mid Test?

Two-storey and double-storey extensions almost always need a full householder application to Test Valley 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 Mid Test address specifically.

How long does Test Valley Borough Council take to decide an extension application?

A householder planning application in Mid Test 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. Test Valley Borough Council is the decision-maker.

Will my extension in Mid Test need building regulations approval as well as planning?

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 Test Valley Borough Council's building control or an approved inspector can sign the work off. This applies to your Mid Test address specifically.

How much do extension plans in Mid Test cost?

Every house and brief is different, so we price each Mid Test extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Test Valley Borough Council approves, and we tell you upfront whether your extension qualifies as permitted development. Call 020 7864 7245 to get started.

Planning approval report

Know your approval odds before you spend a penny on drawings

Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.

House extension plans across Test Valley

Same fixed quotes, same fast drawings — wherever your project is.

Other planning services in Mid Test