Harlow, Essex
Glazed rear extension in Harlow
Thinking about a glazed rear extension in Harlow? Full-height glass, slim frames and big rooflights for the most open rear room. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Harlow and its postcode districts CM17, CM18, CM19 and CM20 are part of our Essex coverage. 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 Harlow?
A glazed rear extension in Harlow is priced at £2,970–£5,090 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 Harlow?
Planning for a glazed rear extension in Harlow follows the English householder rules.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres 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 Harlow like to extend?
Post-war semis and newer estates are typical of Harlow, 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 Harlow 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.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Glazed rear extensions near Harlow
We also build glazed and glass-box rear extensions in nearby Hoddesdon (5.4 miles) and Epping (5.4 miles).
- Glazed rear extension in Hoddesdon
- Glazed rear extension in Epping
- Glazed rear extension in Broxbourne
- Glazed rear extension in Ware
- Glazed rear extension in Bishops Stortford
Other work in Harlow:
FAQ
Glazed rear extension questions in Harlow
Do I need planning permission for a rear extension in Harlow?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Will a glass extension be too hot?
Not if it is designed for its orientation, with solar-control glass, shading and ventilation.
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.
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.
How long does a rear extension take to build in Harlow?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.