Forest Hill, Greater London
Glazed rear extension in Forest Hill
Glazed rear extension in Forest Hill: full-height glass, slim frames and big rooflights for the most open rear room. We measure the house, show you what the rules allow, price it in writing and build it.
Forest Hill is covered from our Greater London round, including SE4, SE6 and SE23. If your garden in Forest Hill faces south, expect us to talk about overhangs and solar-control glass before frame colours.
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 Forest Hill?
In Forest Hill, our guide for a glazed rear extension is £3,640–£6,240 per square metre including VAT for a standard specification. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £43,500–£75,000 |
| 4 m wide × 6 m deep (24 m²) | £87,500–£150,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a glazed rear extension in Forest Hill?
Here is how the rules in England apply to a glazed rear extension in Forest Hill.
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 Forest Hill like to extend?
Period terraces in Forest Hill sit alongside flats, and the difference matters: houses usually keep permitted development rights, while flats and maisonettes need planning permission for any rear extension.
How a glazed rear extension in Forest Hill 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.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
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 Forest Hill
Neighbouring places we cover include Crofton Park (0.5 miles) and Perry Vale (0.7 miles).
- Glazed rear extension in Crofton Park
- Glazed rear extension in Perry Vale
- Glazed rear extension in Catford
- Glazed rear extension in Ladywell
- Glazed rear extension in Brockley
Other work in Forest Hill:
FAQ
Glazed rear extension questions in Forest Hill
Can you match the brick or stone on my Forest Hill 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 Forest Hill?
As a guide, £3,640–£6,240 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £43,500–£75,000 at that rate. Your written price follows the survey.
Does glass need planning permission?
The same rules apply as any rear extension; glass does not change the depth or height limits.
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.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Is the site visit in Forest Hill free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.