Two-storey extension drawings for St Albans homes — bedroom above, living space below, drawn against the 3-metre projection and 7-metre boundary rules and to St Albans City & District Council's design guidance, delivered in days and revised free until your decision.
St Albans City & District Council granted 88% of the householder planning decisions it made in its latest published year — 1 point above the 87% England-wide householder average. Over 80 per cent of the district is Metropolitan Green Belt, the dominant constraint and the reason the emerging plan must justify green-belt release, 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.
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. St Albans carries at least one Article 4 direction, and conservation areas including St Albans city centre, Fishpool Street and St Michael's Village remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in St Albans is determined against an 8-week statutory target.
St Albans city centre (the medieval and Georgian historic core around the cathedral and Fishpool Street), Harpenden (affluent commuter town of Edwardian and interwar semis and detached houses), Marshalswick (interwar and postwar St Albans suburb of detached houses and semis), Redbourn (historic village with a large common, period cottages and modern infill), Wheathampstead (historic village between St Albans and Harpenden) and London Colney (large village with mixed twentieth-century estate housing) — these are the St Albans pockets our drawings cover most. Heritage designations here include St Albans city centre, Fishpool Street, St Michael's Village, Verulamium, Harpenden and Redbourn. St Albans City & District Council weighs each proposal against the saved 1994 St Albans District Local Plan Review, with a new Local Plan to 2041 at examination, where the historic city core carries dense conservation coverage layered over the scheduled Roman remains at Verulamium. Converted flats concentrate in the city centre and along the commuter-rail corridors, and carry no householder permitted-development rights.. On roofs the borough is pitched plain-clay-tile roofs on the historic core and hipped roofs on the interwar suburban semis, over medieval, Georgian and Victorian stock in the historic city core, Victorian and Edwardian commuter terraces, interwar and postwar suburban semis and detached houses in Marshalswick, Harpenden and the larger villages and period cottages in the green-belt villages.
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. St Albans is largely medieval, Georgian and Victorian stock in the historic city core, Victorian and Edwardian commuter terraces, interwar and postwar suburban semis and detached houses in Marshalswick, Harpenden and the larger villages and period cottages in the green-belt villages, and pitched plain-clay-tile roofs on the historic core and hipped roofs on the interwar suburban 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.
Over 80 per cent of the district is Metropolitan Green Belt, the dominant constraint and the reason the emerging plan must justify green-belt release. The Verulam and Fishpool Street Article 4 direction, covering the historic core around Fishpool Street and St Michael's, removes permitted-development rights so even minor external changes to these medieval and Georgian frontages need consent.
Some two-storey rear extensions are permitted development. You will need a full application to St Albans City & District 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 St Albans City & District Council checks first — then submit a validation-complete pack.
Below is St Albans City & District Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. St Albans grants a fair share of householder applications, with near-total green-belt coverage and the sensitivity of the historic city core the constraints behind most refusals. 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 St Albans city centre, Harpenden and Marshalswick, 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 medieval, georgian and victorian stock in the historic city core, 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 historic city core carries dense conservation coverage layered over the scheduled Roman remains at Verulamium. 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 St Albans. A few of the areas where they come up most often:
Two storey extension drawings for St Albans city centre — the medieval and Georgian historic core around the cathedral and Fishpool Street — dimensioned against the 3m and 7m limits and drawn to St Albans City & District Council's guidance.
Two storey extension drawings for Harpenden — affluent commuter town of Edwardian and interwar semis and detached houses — dimensioned against the 3m and 7m limits and drawn to St Albans City & District Council's guidance.
Two storey extension drawings for Marshalswick — interwar and postwar St Albans suburb of detached houses and semis — dimensioned against the 3m and 7m limits and drawn to St Albans City & District Council's guidance.
Two storey extension drawings for Redbourn — historic village with a large common, period cottages and modern infill — dimensioned against the 3m and 7m limits and drawn to St Albans City & District Council's guidance.
Two storey extension drawings for Wheathampstead — historic village between St Albans and Harpenden — dimensioned against the 3m and 7m limits and drawn to St Albans City & District Council's guidance.
Two storey extension drawings for London Colney — large village with mixed twentieth-century estate housing — dimensioned against the 3m and 7m limits and drawn to St Albans City & District 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 St Albans City & District 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 St Albans City & District Council validates and decides two-storey applications.
Send us your St Albans postcode and garden depth. We measure the 7-metre boundary rule against your plot, confirm designation status, and score your odds against live St Albans City & District 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 St Albans City & District 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 St Albans, the 7-metre rule is what most commonly forces a full application to St Albans City & District 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 St Albans gardens this is decisive, and we measure it on survey before any design work rather than discovering it at validation. St Albans City & District Council is the decision-maker.
Not under permitted development — two-storey side extensions always need a full application to St Albans City & District 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.
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 St Albans address specifically. St Albans City & District 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 St Albans City & District Council's planning decision, so we flag the notice period early and detail the junction on the drawings.
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 St Albans address specifically. St Albans City & District Council is the decision-maker.
We quote each St Albans 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 St Albans City & District Council approves. Call 020 7864 7245 to start.
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