Longfield, Kent
Glazed rear extension in Longfield
Full-height glass, slim frames and big rooflights for the most open rear room. If you live in Longfield and want to know what a glazed rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Longfield sits in Kent, with postcode districts including DA3, DA4 and DA13. 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 Longfield?
Guide prices for a glazed rear extension in Longfield start from our South East England rate of £3,140–£5,380 per square metre, including VAT. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £37,500–£64,500 |
| 4 m wide × 6 m deep (24 m²) | £75,500–£129,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a glazed rear extension in Longfield?
The planning route for a glazed rear extension in Longfield is set by England's householder rules and your council.
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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Longfield like to extend?
Longfield has a mix of Victorian terraces near the centre and larger Edwardian and inter-war houses further out. Clay soils across much of the South East mean deeper foundations near trees, which we plan for at the survey.
How a glazed rear extension in Longfield comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
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 Longfield
Close by, we work in Hartley, about 0.7 miles away, and Swanscombe, about 3.5 miles away.
- Glazed rear extension in Hartley
- Glazed rear extension in Swanscombe
- Glazed rear extension in Gravesend
- Glazed rear extension in Dartford
- Glazed rear extension in Tilbury
Other work in Longfield:
FAQ
Glazed rear extension questions in Longfield
What postcode areas do you cover around Longfield?
Including DA3, DA4 and DA13, and the surrounding Kent area.
How long does a rear extension take to build in Longfield?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Is a glass box a conservatory?
No. It is built to Building Regulations as part of the house, with insulated floor and roof, so it is usable all year.
Can you match the brick or stone on my Longfield house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How much does a glazed rear extension cost in Longfield?
As a guide, £3,140–£5,380 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £37,500–£64,500 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.