Hertfordshire
Side return extensions in Hertfordshire
Infilling the narrow passage beside a Victorian or Edwardian back addition. Across Hertfordshire we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Watford, Hemel Hempstead and Stevenage.

Side return projects in Watford usually start with a drainage survey of the side passage. Post-war semis and newer estates are typical of Hertfordshire, 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 much does a side return extension cost in Hertfordshire?
A side return extension in Hertfordshire is priced at £2,440–£4,030 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 |
|---|---|
| 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 in Hertfordshire?
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.
Where in Hertfordshire do we work?
- Watford
- Hemel Hempstead
- Stevenage
- St Albans
- Welwyn Garden City
- Cheshunt
- Hatfield
- Bishops Stortford
- Borehamwood
- Hitchin
- Hoddesdon
- Letchworth Garden City
- North Watford
- Harpenden
- Bushey
- Hertford
- Rickmansworth
- Potters Bar
- Berkhamsted
- Ware
- Enfield Lock
- Royston
- Croxley Green
- Broxbourne
- West Watford
- Batchworth
- Tring
- Chorleywood
- Codicote
- Baldock
- Abbots Langley
- Waltham Cross
FAQ
Questions people ask
How much space does a side return add?
Typically 8 to 18 square metres, enough to turn a galley kitchen into a kitchen-diner with an island.
Do I need my neighbour's permission?
Not their permission, but in England and Wales you must serve party wall notices, and a neighbour can consent in writing or ask for a surveyor's award.
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.
Do you cover all of Hertfordshire?
We cover 32 towns and districts in Hertfordshire, including Watford, Hemel Hempstead and Stevenage.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.