Forest Hill, Greater London
Side return extension in Forest Hill
Side return extension in Forest Hill: infilling the narrow passage beside a Victorian or Edwardian back addition. We measure the house, show you what the rules allow, price it in writing and build it.
We cover Forest Hill (SE4, SE6 and SE23) as part of our Greater London work. In Forest Hill we check the boundary line and the neighbour's gutter before drawing a side return, because a few centimetres decide whether the wall goes on or beside the boundary.
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 side return extension cost in Forest Hill?
A side return extension in Forest Hill is priced at £2,990–£4,940 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 |
|---|---|
| 2 m wide × 6 m deep (12 m²) | £36,000–£59,500 |
| 2.5 m wide × 7 m deep (17.5 m²) | £52,500–£86,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a side return extension in Forest Hill?
Planning for a side return extension in Forest Hill follows the English householder rules.
Side return infills and the side leg of a wraparound are treated as side extensions in England: single-storey, no more than 4 metres high and no wider than half the original house. They are not permitted development in conservation areas, National Parks or National Landscapes, and a joined wraparound often needs a planning application because the side and rear rules apply together.
The Party Wall etc. Act 1996 applies in England: you serve notice two months before work to a shared wall, and one month before digging foundations within 3 metres (or 6 metres for deeper foundations) of a neighbour's building. Neighbours can agree in writing; if they dissent, surveyors agree an award.
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 side return extension in Forest Hill comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
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.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Side return extensions near Forest Hill
Neighbouring places we cover include Crofton Park (0.5 miles) and Perry Vale (0.7 miles).
- Side return extension in Crofton Park
- Side return extension in Perry Vale
- Side return extension in Catford
- Side return extension in Ladywell
- Side return extension in Brockley
Other work in Forest Hill:
FAQ
Side return extension questions in Forest Hill
How long does a rear extension take to build in Forest Hill?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
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.
Glass roof or solid roof with rooflights?
A glass roof gives the most light; a solid roof with long rooflights is warmer and quieter in rain. Both work.
Is the site visit in Forest Hill free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How much does a side return extension cost in Forest Hill?
As a guide, £2,990–£4,940 per square metre including VAT for a standard specification. For example, 2 m wide × 6 m deep (12 m²): about £36,000–£59,500 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.