Harpenden, Hertfordshire
Side return extension in Harpenden
Side return extension in Harpenden: 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 Harpenden (AL5) as part of our Hertfordshire work. Side return projects in Harpenden usually start with a drainage survey of the side passage.
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 Harpenden?
For Harpenden we work from the East of England rate: £2,440–£4,030 per square metre of new floor, including VAT, 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 |
|---|---|
| 2 m wide × 6 m deep (12 m²) | £29,500–£48,500 |
| 2.5 m wide × 7 m deep (17.5 m²) | £42,500–£70,500 |
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 Harpenden?
Here is how the rules in England apply to a side return extension in Harpenden.
In England the side part of a side return or wraparound must meet the side-extension rules (one storey, under 4 metres high, no more than half the width of the original house), and those rights do not apply on designated land. Because a wraparound combines a side and a rear extension, many need householder planning permission.
Because rear extensions often sit on or near the boundary, the Party Wall etc. Act 1996 usually applies in England. Notices go out one or two months before work depending on the type of work, and a surveyor's award is only needed if a neighbour does not consent.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Harpenden like to extend?
Post-war semis and newer estates are typical of Harpenden, 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 side return extension in Harpenden 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.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
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 Harpenden
From Harpenden, the nearest places we also cover are St Albans (4.7 miles) and Luton (5.0 miles).
- Side return extension in St Albans
- Side return extension in Luton
- Side return extension in Codicote
- Side return extension in Hemel Hempstead
- Side return extension in Welwyn Garden City
Other work in Harpenden:
FAQ
Side return extension questions in Harpenden
Is the site visit in Harpenden 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 I combine a side return with a rear extension?
Yes; that is a wraparound extension, and it gives the biggest open-plan room a terrace can have.
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.
What postcode areas do you cover around Harpenden?
Including AL5, and the surrounding Hertfordshire area.
How much does a side return extension cost in Harpenden?
As a guide, £2,440–£4,030 per square metre including VAT for a standard specification. For example, 2 m wide × 6 m deep (12 m²): about £29,500–£48,500 at that rate. Your written price follows the survey.