Single-storey, double-storey, rear and side extension drawings for Hounslow homes — measured to Hounslow Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
Hounslow Council granted 86% of the householder planning decisions it made in its latest published year — 1 point below the 87% England-wide householder average. Side-return and mansard schemes dominate in Chiswick, where officers weigh roof bulk against a strongly uniform terrace roofscape, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837), Victorian (1837–1901), Edwardian (1901–1910), interwar (1918–1939) and postwar (1945–1970) 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. Hounslow carries at least one Article 4 direction, and conservation areas including Bedford Park, Old Chiswick and Strand-on-the-Green remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Hounslow is determined against an 8-week statutory target.
Chiswick (Victorian and Edwardian terraces wrapped around the Bedford Park garden suburb), Brentford (older riverside terraces alongside recent waterfront redevelopment), Isleworth (the Old Isleworth riverside conservation area and Georgian frontages), Osterley (interwar semis on the fringe of Osterley Park), Feltham (postwar and interwar suburban estates to the south-west) and Hounslow (the town centre with mixed terraces and converted flats) — these are the Hounslow pockets our drawings cover most. Heritage designations here include Bedford Park, Old Chiswick, Strand-on-the-Green, Wellesley Road and Old Isleworth. Hounslow Council weighs each proposal against Hounslow Local Plan and the Residential Extension Guidelines SPD, where the borough's western edge sits under Heathrow flight paths, so glazing, ventilation and noise mitigation surface on larger schemes. Converted terraces are common through central Chiswick and Brentford, and flats and maisonettes carry no householder permitted-development rights.. On roofs the borough is London butterfly and valley roofs on the Chiswick terraces and hipped roofs on the interwar semis, over Victorian and Edwardian terraces across Chiswick, interwar semi-detached houses around Osterley and Hounslow and converted period flats and maisonettes.
Hounslow homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from Victorian and Edwardian terraces across Chiswick, interwar semi-detached houses around Osterley and Hounslow and converted period flats and maisonettes, 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. Hounslow Council judges every one of them against Hounslow Local Plan and the Residential Extension Guidelines SPD, 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. Side-return and mansard schemes dominate in Chiswick, where officers weigh roof bulk against a strongly uniform terrace roofscape, so we design around it from the first sketch rather than discover it at validation.
Hounslow also protects whole streets — Bedford Park, Old Chiswick, Strand-on-the-Green, Wellesley Road and Old Isleworth among them. Bedford Park — the pioneering garden suburb shared with Ealing — carries a long-standing Article 4 direction, and the Chiswick and Old Isleworth conservation areas remove permitted-development rights on many of their period 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.
Plenty of Hounslow 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 Hounslow Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Hounslow Council's officers weigh first — and submit a validation-complete pack, whether that is a lawful development certificate, a prior-approval notification or a full householder application.
Below is Hounslow Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Hounslow grants a fair share of householder applications, with terrace roofscape in the Chiswick conservation areas the dominant constraint on loft and rear schemes. 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, rolling year). 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 Chiswick, Brentford and Isleworth, 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 edwardian terraces across chiswick, a side-return infill frequently pairs with it to square off the plan; on wider converted period flats and maisonettes, a two-storey side or rear extension can add a bedroom above without swallowing the garden.
The borough's western edge sits under Heathrow flight paths, so glazing, ventilation and noise mitigation surface on larger schemes. 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 Hounslow 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.
We draw extensions on every street in the borough. A few of the neighbourhoods where Hounslow projects come up most often:
Extension drawings for Chiswick's Victorian and Edwardian terraces wrapped around the Bedford Park garden suburb — footprint-checked, daylight-tested and drawn to Hounslow Council's guidance.
Extension drawings for Brentford's older riverside terraces alongside recent waterfront redevelopment — footprint-checked, daylight-tested and drawn to Hounslow Council's guidance.
Extension drawings for Isleworth's the Old Isleworth riverside conservation area and Georgian frontages — footprint-checked, daylight-tested and drawn to Hounslow Council's guidance.
Extension drawings for Osterley's interwar semis on the fringe of Osterley Park — footprint-checked, daylight-tested and drawn to Hounslow Council's guidance.
Extension drawings for Feltham's postwar and interwar suburban estates to the south-west — footprint-checked, daylight-tested and drawn to Hounslow Council's guidance.
Extension drawings for Hounslow's the town centre with mixed terraces and converted flats — footprint-checked, daylight-tested and drawn to Hounslow Council's guidance.
The right extension in Hounslow 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 type | Permitted development? | What it adds | What Hounslow Council checks |
|---|---|---|---|
| Single-storey rear | Often, within 3m/4m depth (6m/8m via prior approval) | Bigger kitchen-diner across the back | Depth, height, neighbour daylight (45°) |
| Side-return infill | Sometimes, if within width and height limits | Squares off an L-shaped ground floor | Width vs the original house, glazing to boundary |
| Two-storey rear/side | No — full application | Extra bedroom or bathroom above | Bulk, overlooking, 7m rear-boundary gap |
| Wraparound (rear + side) | No — full application | Whole-width open-plan ground floor | Combined footprint and garden retained |
Route depends on your street — conservation areas such as Bedford Park and Old Chiswick and Article 4 directions can remove permitted-development rights.
A fixed process built around how Hounslow Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Hounslow 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 Hounslow Council decisions.
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.
Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Hounslow Council's extension design guidance.
We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Hounslow Council issues its decision.
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 Hounslow you will need to apply to Hounslow 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 Bedford Park and Old Chiswick.
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 Hounslow Council and a neighbour-consultation period, and it does not apply on designated land such as Hounslow's conservation areas. We confirm which route your property qualifies for before drawing.
Two-storey and double-storey extensions almost always need a full householder application to Hounslow 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.
A householder planning application in Hounslow 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. Hounslow Council is the decision-maker.
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 Hounslow Council's building control or an approved inspector can sign the work off.
Every house and brief is different, so we price each Hounslow extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Hounslow Council approves, and we tell you upfront whether your extension qualifies as permitted development. Call 020 7864 7245 to get started.
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.
Same fixed quotes, same fast drawings — wherever your project is.