Two-storey extension drawings for Westbury-on-Trym homes — bedroom above, living space below, drawn against the 3-metre projection and 7-metre boundary rules and to Bristol City Council's design guidance, delivered in days and revised free until your decision.
Bristol City Council granted 85% of the householder planning decisions it made in its latest published year — 2 points below the 87% England-wide householder average. The Westbury on Trym conservation area protects the medieval village layout, the gatehouse setting and the older cottage frontages, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837), Edwardian (1901–1910), interwar (1918–1939) and postwar (1945–1970) housing stock sets the design brief on most streets.
Under Class B, a rear dormer stays permitted development up to 40m³ of added roof volume on a terrace or 50m³ on a semi-detached or detached house, while Class A allows a single-storey rear extension of 3m beyond the original rear wall on a terrace and 4m on a detached house before a full application is needed. Westbury-on-Trym carries at least one Article 4 direction, and conservation areas including Westbury on Trym, Kingsweston and Trym Valley and The Downs remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Westbury-on-Trym is determined against an 8-week statutory target.
Westbury village (historic cottages and Georgian houses around the old college gatehouse), Henleaze (Edwardian and interwar family houses on tree-lined avenues), Canford (interwar semis toward the Downs and cemetery), Trym Valley (houses along the wooded river corridor to Sea Mills) and Eastfield (1930s semi-detached suburbia on the Henleaze border) — these are the Westbury-on-Trym pockets our drawings cover most. Heritage designations here include Westbury on Trym, Kingsweston and Trym Valley and The Downs. Bristol City Council weighs each proposal against Bristol Local Plan / Core Strategy and the emerging Local Plan, where the Kingsweston and Trym Valley area guards the wooded river corridor and its landscape setting. Converted flats are uncommon here, but larger houses split into flats near the village centre carry no householder permitted-development rights.. On roofs the borough is pitched and gabled roofs on the village cottages and hipped roofs on the interwar semis, over historic village cottages and Georgian houses, interwar semi-detached suburbia and Edwardian and post-war detached houses.
Adding at first floor changes the question the case officer asks. A single-storey extension is judged mostly on daylight and garden loss; a two-storey extension is judged on overlooking, bulk against the neighbouring roofline, and whether it reads as part of the house or bolted onto it. Westbury-on-Trym is largely historic village cottages and Georgian houses, interwar semi-detached suburbia and Edwardian and post-war detached houses, and pitched and gabled roofs on the village cottages and hipped roofs on the interwar semis set what a matching roof actually means here.
The permitted-development route exists but is narrow: 3 metres of rear projection, a 7-metre stand-off from the rear boundary, eaves and ridge no higher than the original, and side-facing upper windows obscure-glazed and non-opening below 1.7 metres above floor level. Most two-storey schemes fail one of those, usually the 7-metre boundary rule on a shorter garden, and go in as a full application instead. We establish which route applies before designing, because it changes the drawing set.
The Westbury on Trym conservation area protects the medieval village layout, the gatehouse setting and the older cottage frontages. Westbury-on-Trym's historic village core is a conservation area and the district is also covered by Bristol's city-wide Article 4 HMO direction, so both alterations in the old village and shared-house conversions need planning permission.
Some two-storey rear extensions are permitted development. You will need a full application to Bristol City Council if any of these apply:
We set the projection and boundary distance on the site plan, prove the roof-pitch match on the elevations, and specify obscure glazing on the side windows — the three things Bristol City Council checks first — then submit a validation-complete pack.
Below is Bristol City Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Westbury-on-Trym approves most householder applications; the historic village conservation core and the Trym valley setting are what constrain the schemes that struggle. Two-storey schemes attract more neighbour comment than any other householder work, so the overlooking and daylight case has to be made on the drawings.
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 Westbury village, Henleaze and Canford, the schemes that succeed set the first floor back from the ground floor, keep the ridge below the original, and treat the flank wall as blank or obscure-glazed. On historic village cottages and georgian houses, matching the eaves line matters more than matching the brick: an extension that carries the existing eaves through reads as original even in a different material.
The Kingsweston and Trym Valley area guards the wooded river corridor and its landscape setting. We draw the 45-degree daylight test from the neighbour's nearest habitable window, show the window positions in section, and set out the steel and foundation implications early — a two-storey extension changes the load path, so the structural design and the planning design have to be developed together rather than in sequence.
We draw two-storey extensions across Westbury-on-Trym. A few of the areas where they come up most often:
Two storey extension drawings for Westbury village — historic cottages and Georgian houses around the old college gatehouse — dimensioned against the 3m and 7m limits and drawn to Bristol City Council's guidance.
Two storey extension drawings for Henleaze — Edwardian and interwar family houses on tree-lined avenues — dimensioned against the 3m and 7m limits and drawn to Bristol City Council's guidance.
Two storey extension drawings for Canford — interwar semis toward the Downs and cemetery — dimensioned against the 3m and 7m limits and drawn to Bristol City Council's guidance.
Two storey extension drawings for Trym Valley — houses along the wooded river corridor to Sea Mills — dimensioned against the 3m and 7m limits and drawn to Bristol City Council's guidance.
Two storey extension drawings for Eastfield — 1930s semi-detached suburbia on the Henleaze border — dimensioned against the 3m and 7m limits and drawn to Bristol City Council's guidance.
The first-floor limits are tighter than the ground-floor ones. This is how the common cases compare.
| Scheme | Permitted development? | Deciding limit | What Bristol City Council checks |
|---|---|---|---|
| Two-storey rear, 3m projection, 7m+ to boundary | Often yes | 3m projection / 7m boundary | Roof match, side-window glazing |
| Two-storey rear, under 7m to boundary | No — full application | Rear-boundary distance | Overlooking, daylight, garden loss |
| Two-storey side extension | No — full application | Side elevation | Gap to boundary, street rhythm |
| Two-storey wraparound | No — full application | Combined footprint | Bulk, massing, neighbour amenity |
| Any two-storey on designated land | No — full application | Designation | Character and appearance |
Limits from the GPDO 2015, Schedule 2, Part 1, Class A — two-storey rear extension conditions.
A fixed process built around how Bristol City Council validates and decides two-storey applications.
Send us your Westbury-on-Trym postcode and garden depth. We measure the 7-metre boundary rule against your plot, confirm designation status, and score your odds against live Bristol City Council decisions.
We measure the original rear wall, eaves and ridge heights, garden depth and every neighbouring window that faces the site — the inputs the daylight and overlooking case is built from.
Chartered designers develop the two-storey addition to your brief with the roof and eaves resolved, and we coordinate the load path so the structural scheme and the planning scheme are the same building.
We submit the application, manage validation and case-officer queries, and revise the drawings free until Bristol City Council issues its decision.
Often, but not always. A two-storey rear extension can be permitted development if it projects no more than 3 metres, sits at least 7 metres from the rear boundary, does not exceed the existing eaves and ridge, and has obscure-glazed non-opening side windows below 1.7 metres. In Westbury-on-Trym, the 7-metre rule is what most commonly forces a full application to Bristol City Council.
No part of a permitted-development two-storey rear extension may come within 7 metres of the boundary opposite the rear wall of the house. It exists to protect the neighbour behind you from being overlooked at first floor. On shorter Westbury-on-Trym gardens this is decisive, and we measure it on survey before any design work rather than discovering it at validation. Bristol City Council is the decision-maker.
Not under permitted development — two-storey side extensions always need a full application to Bristol City Council. They are assessed on the gap to the boundary, whether the street's rhythm of spaces between houses survives, and whether the extension is subordinate to the original. Setting the first floor back from the front building line and down from the ridge is what usually makes the difference. This applies to your Westbury-on-Trym address specifically.
Overlooking is the most common objection, and it is answerable on the drawings. We position habitable-room windows away from neighbouring gardens, obscure-glaze and fix shut anything on the flank below 1.7 metres, and show the sight lines in section. Where the geometry is tight, a rooflight or a high-level window gives the same daylight without the mutual overlooking that draws objections. This applies to your Westbury-on-Trym address specifically. Bristol City Council is the decision-maker.
Almost certainly. Excavating within 3 metres of a neighbouring structure and building on or up to the boundary both trigger the Party Wall etc. Act 1996, and a two-storey extension usually does both. It is entirely separate from Bristol City Council's planning decision, so we flag the notice period early and detail the junction on the drawings. This applies to your Westbury-on-Trym address specifically.
Yes. Adding a floor changes the load path from roof to foundation, so beams, padstones and foundation depths all need designing and calculating for building control. Planning and building regulations are separate consents, and the structural set is what building control assesses — we prepare both so the approved scheme is the buildable one. This applies to your Westbury-on-Trym address specifically. Bristol City Council is the decision-maker.
We quote each Westbury-on-Trym two-storey extension individually, because plot depth, roof form and structural complexity vary house to house, and send a fixed, no-obligation quote within one working day. It covers the drawing pack with free revisions until Bristol City Council approves. Call 020 7864 7245 to start.
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