Timber frame extensions in St Austell: design, approvals and build
Planning a timber frame extension in St Austell? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in St AustellFrom £21,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsPL25

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.
The planning position for a specific St Austell address depends on its history and any designations, which is why we check it at the first visit.
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.
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).
Guide prices for St Austell
For St Austell we adjust our national guide rates by ×1.02, the factor we use for South West England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in St Austell: £1,780 to £3,470 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £21,000 – £26,000 | £25,000 – £32,500 | £31,500 – £42,000 |
| 4 m × 5 m 20 m² | £35,500 – £43,000 | £41,500 – £54,500 | £53,000 – £69,500 |
| 5 m × 6 m 30 m² | £53,500 – £64,500 | £62,500 – £81,500 | £79,500 – £104,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Covering St Austell
We cover St Austell and the postcode districts PL25. Nearby, we also take on projects in Bodmin (9 miles), Truro (13 miles), Newquay (14 miles), Falmouth (18 miles).
Plymouth, in Devon, is roughly 28 miles from St Austell and also on our list. South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
What we take care of
- Frame design and structural calculations
- Breathable wall build-up with insulation
- Fire and acoustic details where needed
- Cladding, render or brick slip finish
- Foundations, often lighter than masonry
Moisture is the enemy of any timber building. We design ventilated cladding cavities, breather membranes and a proper damp-proof course height, and keep the frame dry during construction.
From first visit to completion
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
We visit your St Austell home, measure up, talk through what you want and check the planning position.
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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
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
Who do I contract with for a timber frame extension in St Austell?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
How long does a timber frame extension take to build in St Austell?
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 Austell?
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 £1,780 to £3,470 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 Austell
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.