Home office extensions for homes in Hertfordshire
Our design and build teams take on home office extensions in Hertfordshire, from the first measured survey through planning and building control to the finished room.
- Guide priceFrom £16,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Towns covered18
- Site visitFree, no obligation

Towns in Hertfordshire
Covering Hertfordshire
Towns we cover in Hertfordshire include Watford, Hemel Hempstead, Stevenage, St Albans, Welwyn Garden City, Cheshunt, Hatfield, Bishop's Stortford. The East of England mixes market-town terraces, inter-war semis and modern estates. Clay soils are common in parts of the region, which can affect foundation design.
Do I need planning permission in Hertfordshire?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
When a home office extension makes sense
- Households that need a second quiet room
- People who work from home most of the week
- Homes where a loft or garden room is not practical
North-facing glass and rooflights give steadier light for screen work. Where the office faces south, we use deeper reveals or external shading to keep glare and heat down.
What should I budget for a home office extension in Hertfordshire?
For Hertfordshire we adjust our national guide rates by ×1.06, the factor we use for East of England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Hertfordshire: £1,960 to £3,600 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 3.2 m 8 m² | £16,500 – £20,500 | £18,000 – £23,000 | £22,500 – £29,000 |
| 3 m × 3.6 m 11 m² | £21,500 – £26,000 | £25,000 – £31,500 | £31,000 – £40,000 |
| 3 m × 5 m 15 m² | £29,000 – £35,000 | £34,000 – £43,000 | £42,500 – £54,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions people ask about home office extensions
How long does a home office extension take to build in Hertfordshire?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
Will my neighbours in Hertfordshire be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Hertfordshire, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How much does a home office extension cost?
Our guide range is about £1,960 to £3,600 per m² including VAT. An 11 m² standard-spec office is typically £25,000 to £31,500 in Hertfordshire.
Is an attached office better than a garden office?
An attached office shares the house heating and broadband, adds floor area to the home, and needs no garden path in the rain. A garden building can be cheaper and quicker but is a separate structure.
Book a free site visit in Hertfordshire
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.