Baldock, Hertfordshire
Semi-detached rear extension in Baldock
Thinking about a semi-detached rear extension in Baldock? Single or two-storey extensions for semi-detached houses, with side access and one party wall. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Baldock is covered from our Hertfordshire round, including SG6 and SG7. Where a Baldock semi already has a small lean-to at the back, we usually replace it rather than extend it.
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 semi-detached rear extension cost in Baldock?
A semi-detached rear extension in Baldock is priced at £2,010–£3,290 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 |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £24,000–£39,500 |
| 4 m wide × 5 m deep (20 m²) | £40,500–£65,500 |
| 4 m wide × 6 m deep (24 m²) | £48,500–£79,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a semi-detached rear extension in Baldock?
Here is how the rules in England apply to a semi-detached rear extension in Baldock.
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.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
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 Baldock like to extend?
Baldock mixes Victorian terraces with 1930s semis, so both side returns and full-width kitchen extensions suit houses here.
How a semi-detached rear extension in Baldock 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.
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.
Semi-detached rear extensions near Baldock
From Baldock, the nearest places we also cover are Letchworth Garden City (1.7 miles) and Hitchin (4.9 miles).
- Semi-detached rear extension in Letchworth Garden City
- Semi-detached rear extension in Hitchin
- Semi-detached rear extension in Henlow
- Semi-detached rear extension in Stevenage
- Semi-detached rear extension in Biggleswade
Other work in Baldock:
FAQ
Semi-detached rear extension questions in Baldock
Do I need planning permission for a rear extension in Baldock?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Can you match the brick or stone on my Baldock house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How long does a semi extension take?
10 to 16 weeks on site for a single-storey extension.
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 Baldock free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
What postcode areas do you cover around Baldock?
Including SG6 and SG7, and the surrounding Hertfordshire area.