Orangery and conservatory drawings for St Albans homes — checked against the Class A rear limits and the 30m² building-regulations exemption, drawn to St Albans City & District Council's guidance 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.
The difference is not marketing. A conservatory is predominantly glazed — at least three quarters of the roof and half of the walls — which is what earns it the building-regulations exemption. An orangery has a solid masonry perimeter with a glazed lantern set into a flat roof, so it usually reads as a conventional extension for building control and has to meet Part L thermal standards, Part A structure and Part B fire like any other room.
Both are judged the same way for planning: as rear extensions, against the Class A depth, height and eaves limits, and against the saved 1994 St Albans District Local Plan Review, with a new Local Plan to 2041 at examination. 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 the design question is usually whether the glazing reads as a lightweight addition to that stock or as a bolted-on conservatory kit. On period houses, an orangery with a properly proportioned lantern almost always sits better than a full-height glazed box.
In conservation areas such as St Albans city centre and Fishpool Street, rear glazing is assessed on visibility from the street and on the effect on the rear elevation's character. 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.
Many conservatories are permitted development. You will need an application to St Albans City & District Council where any of these apply:
We check the scheme against the Class A planning limits and against the building-regulations exemption at the same time, so you know before committing whether you are building an exempt conservatory or a fully regulated room.
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. Glazed rear additions are judged on depth, eaves height and how the glazing meets the existing elevation.
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 keep the eaves below the neighbour's ground-floor cill line, set the glazing back from the boundary, and use a solid parapet or brick perimeter to tie the addition into the house. On medieval, georgian and victorian stock in the historic city core, a lantern set in a flat roof usually reads better than a pitched glazed roof, and it avoids the summer overheating that makes full conservatories unusable for months a year.
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 decision worth making early is whether to keep the separating doors. Keeping them preserves the building-regulations exemption but leaves you with a room that is not part of the house; removing them creates one continuous space but brings the whole addition inside Part L, which changes the glazing specification and usually the heating design too. We set out both versions before you commit.
We draw glazed rear additions across St Albans. A few of the areas where they come up most often:
Orangery and conservatory drawings for St Albans city centre — the medieval and Georgian historic core around the cathedral and Fishpool Street — checked against the Class A limits and drawn to St Albans City & District Council's guidance.
Orangery and conservatory drawings for Harpenden — affluent commuter town of Edwardian and interwar semis and detached houses — checked against the Class A limits and drawn to St Albans City & District Council's guidance.
Orangery and conservatory drawings for Marshalswick — interwar and postwar St Albans suburb of detached houses and semis — checked against the Class A limits and drawn to St Albans City & District Council's guidance.
Orangery and conservatory drawings for Redbourn — historic village with a large common, period cottages and modern infill — checked against the Class A limits and drawn to St Albans City & District Council's guidance.
Orangery and conservatory drawings for Wheathampstead — historic village between St Albans and Harpenden — checked against the Class A limits and drawn to St Albans City & District Council's guidance.
Orangery and conservatory drawings for London Colney — large village with mixed twentieth-century estate housing — checked against the Class A limits and drawn to St Albans City & District Council's guidance.
The planning test is the same for both. The building-regulations test is not.
| Structure | Planning route | Building regulations | Practical effect |
|---|---|---|---|
| Conservatory under 30m², doors retained | Class A rear extension limits | Largely exempt | Cheaper build, unheated in winter |
| Conservatory, doors removed | Class A rear extension limits | Part L applies in full | Continuous space, higher spec glazing |
| Orangery with solid perimeter and lantern | Class A rear extension limits | Fully regulated | Usable year round, better on period houses |
| Any of the above beyond the depth limits | Full householder application | As above | 8-week determination |
| Any of the above on designated land | Full householder application | As above | Design and visibility assessed |
Planning limits from the GPDO 2015, Schedule 2, Part 1, Class A; exemption criteria from the Building Regulations 2010, Schedule 2, Class 7.
A fixed process covering both consents, because they pull in different directions.
Send us your St Albans postcode and house type. We confirm the Class A limits that apply, check designation status, and score your odds against live St Albans City & District Council decisions.
We measure the rear elevation, eaves and ground levels, and the neighbouring boundary — the numbers that decide both the projection limit and the 2-metre eaves rule.
Chartered designers develop the orangery or conservatory to your brief, and we set out clearly whether it stays inside the building-regulations exemption or becomes a fully regulated room.
We submit the certificate or application, manage validation and officer queries, and revise free until St Albans City & District Council decides.
Often not. A conservatory is treated as a rear extension, so it can be permitted development within the Class A limits — 3 metres of projection on a terrace or semi, 4 metres on a detached house, with eaves under 3 metres where it sits within 2 metres of a boundary. In St Albans you will need an application to St Albans City & District Council beyond those limits, and on designated land such as St Albans city centre and Fishpool Street.
A conservatory is largely exempt if it is under 30 square metres, at ground level, separated from the house by external-quality doors, and has at least 75% of its roof and 50% of its walls glazed. Glazing, electrics and any drainage work still have to comply. Remove the separating doors and the exemption falls away — the space becomes part of the house and Part L thermal standards apply. This applies to your St Albans address specifically. St Albans City & District Council is the decision-maker.
For planning, none — both are rear extensions assessed against the same Class A limits by St Albans City & District Council. The difference is in building control: an orangery's solid perimeter and flat roof with a lantern usually means it fails the glazing test for exemption, so it is fully regulated. That is why an orangery costs more to build but is comfortable in January.
Usually yes at the rear, though permitted-development rights are narrower on designated land and an Article 4 direction can remove them entirely. The assessment turns on whether the addition is visible from the street and how it meets the original rear elevation. A restrained orangery in matching brick with a lantern is consistently easier to get through than a proprietary glazed conservatory. This applies to your St Albans address specifically. St Albans City & District Council is the decision-maker.
A fully glazed roof will, unless it is specified for it. That is the practical reason most of our clients end up building an orangery instead: a solid insulated roof perimeter with a lantern gives daylight without the greenhouse effect, and keeps the space usable across the year. We raise it at design stage because it is much cheaper to solve on paper than after the build. This applies to your St Albans address specifically. St Albans City & District Council is the decision-maker.
If you excavate foundations within 3 metres of a neighbouring structure and deeper than its foundations, or build on the boundary itself, the Party Wall etc. Act 1996 applies and notice must be served. That is separate from St Albans City & District Council's planning decision. We flag it at design stage so the notice period does not delay the start on site.
We quote each St Albans orangery or conservatory individually, because the structure and the roof form change the work considerably, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until St Albans City & District Council approves. Call 020 7864 7245 to start.
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