Timber frame extensions across St Albans
From the first sketch to final sign-off, we plan and build timber frame extensions in St Albans and the surrounding Hertfordshire area.
- Guide price in St AlbansFrom £22,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsAL1, AL2, AL3, AL4

Will the council need to approve it?
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.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does a timber frame extension cost in St Albans?
Prices below are for St Albans, using the East of England factor of ×1.06. They are guide ranges including VAT for the build only, not a quote.
Typical rates in St Albans: £1,860 to £3,600 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £22,000 – £27,000 | £26,000 – £34,000 | £33,000 – £43,500 |
| 4 m × 5 m 20 m² | £37,000 – £45,000 | £43,000 – £56,500 | £55,000 – £72,500 |
| 5 m × 6 m 30 m² | £55,500 – £67,000 | £65,000 – £84,500 | £82,500 – £108,500 |
Try the guide-price tool to see a range for your own size and finish.
Working in St Albans
We cover St Albans and the postcode districts AL1, AL2, AL3, AL4. The same team covers Harpenden (5 miles), Hatfield (5 miles), Hemel Hempstead (5 miles), Welwyn Garden City (6 miles), all within easy reach.
Just over the Greater London border, Barnet is about 9 miles away. Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
Is a timber frame extension right for your house?
- Sites where weight or speed matters
- Homeowners who want strong energy performance
- Contemporary designs with timber or board cladding
Our process, step by step
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
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
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Timber frame extension questions answered
Will my neighbours in St Albans 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.
How long does a timber frame extension take to build in St Albans?
On site, typically 8 to 14 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Do I need building regulations approval in St Albans?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Is timber frame cheaper than brick?
It is similar overall. The frame can save time on site, but the cladding choice has a big effect on cost. Our guide range is about £1,860 to £3,600 per m² including VAT.
Does a timber frame extension need planning permission?
The same planning rules apply as for any extension. If the cladding looks different from the house, permitted development’s matching-materials condition may mean an application is needed.
Book a free site visit in St Albans
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.