St Albans, Hertfordshire
Glazed rear extension in St Albans
We plan and build glazed and glass-box rear extensions for homeowners in St Albans. Full-height glass, slim frames and big rooflights for the most open rear room. Start with a free site visit, then a written price once the design is agreed.
St Albans is covered from our Hertfordshire round, including AL1 and AL2. A wide sliding door with one long rooflight, rather than a fully glazed roof, keeps a glass-led extension usable in summer.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a glazed rear extension cost in St Albans?
In St Albans, our guide for a glazed rear extension is £2,970–£5,090 per square metre including VAT for a standard specification. East of England prices run slightly above our West Midlands baseline; clay soils near trees are the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £35,500–£61,000 |
| 4 m wide × 6 m deep (24 m²) | £71,000–£122,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a glazed rear extension in St Albans?
Here is how the rules in England apply to a glazed rear extension in St Albans.
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in St Albans like to extend?
Post-war semis and newer estates are typical of St Albans, and many have room for a full-width extension. Shrinkable clay is common in the East of England, so foundations near trees and hedges are designed to NHBC-style depth guidance.
How a glazed rear extension in St Albans comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Glazed rear extensions near St Albans
From St Albans, the nearest places we also cover are Abbots Langley (4.7 miles) and Harpenden (4.7 miles).
- Glazed rear extension in Abbots Langley
- Glazed rear extension in Harpenden
- Glazed rear extension in Hatfield
- Glazed rear extension in Hemel Hempstead
- Glazed rear extension in North Watford
Other work in St Albans:
FAQ
Glazed rear extension questions in St Albans
How much does a glazed rear extension cost in St Albans?
As a guide, £2,970–£5,090 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £35,500–£61,000 at that rate. Your written price follows the survey.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Sliding or bifold doors?
Sliders give bigger panes and slimmer sightlines; bifolds open the whole width. Our guide compares them.
Is the site visit in St Albans free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Can you match the brick or stone on my St Albans house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.