West Cornwall · TR26
House Extensions in Carbis Bay
Extensions are the bread and butter of Cornish homes — adding the kitchen-diner the original layout never had, the bedroom for a growing family, or the light and views the back of the house should always have had. In Carbis Bay, that work is shaped by the place itself — Carbis Bay is the residential coastal suburb of St Ives, climbing up the cliffs above one of the calmest beaches on the north coast and built largely between 1900 and 1970, with a building stock that leans toward Edwardian and 1930s detached villas and post-war bungalows.
- Cornwall AONB
- Coastal exposure zone
Local context
Why Carbis Bay is its own job.
AONB designation covers the whole village; coastal views and cumulative cliffside development are weighed in most applications. Carbis Bay sits inside St Ives parish's principal residence policy area. For extension specifically, the surrounding landscape falls inside the Cornwall Area of Outstanding Natural Beauty, so massing, height and landscape impact carry extra weight in any planning decision; coastal salt-laden air around Carbis Bay drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure. That's why we treat every Carbis Bay project as a TR26-area job first — not a generic Cornwall job with a postcode bolted on.
Planning note
Most extensions in Cornwall are either permitted development or a straightforward householder application — but Conservation Area and AONB sites need a more careful design conversation upfront.
What we focus on
Extensions considerations specific to Carbis Bay.
01
Permitted development for rear extensions runs to four metres on a detached house, three on a semi or terrace — but Article 4 areas remove this in some parishes.
02
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
03
Extensions over a certain proportion of the original house trigger full Part L upgrade obligations to the existing building — worth knowing before brief is set.
Our process
How a Carbis Bay extension project runs.
Step 1
Brief
We meet on site, talk through how you live now and what's missing from the current layout.
Step 2
Design
Two or three sketch directions with rough budgets, then refinement of the chosen route.
Step 3
Approvals
Planning or Cert of Lawfulness, then a full building regs package.
Step 4
Build
Either through your own builder with our drawings, or as a full build by our team.
Step 5
Handover
Snag, certify, hand over the keys to your new space.
Typical single-storey rear extensions run twelve to twenty weeks on site; two-storey and wraparound projects sixteen to thirty weeks.
FAQs
Carbis Bay Extensions — common questions.
- Will my house be liveable during the build?
- For most rear and side extensions, yes — we sequence the works so the kitchen and one bathroom stay functional until the new build is watertight and connected. In Carbis Bay specifically, we'd start by checking AONB landscape sensitivity before committing to a direction.
- How long does the whole process take?
- Allow roughly three months for design and approvals, then twelve to twenty weeks on site for a typical single-storey extension. Wraparounds and two-storey add-ons take longer, mostly through approval and groundworks.
- Do I need planning permission for an extension?
- Often no — single-storey rear extensions, side extensions and modest two-storey additions can sit inside permitted development on a typical detached house. Conservation Areas, AONB and Article 4 zones remove some of those rights, so we always check the address first.
- How much does an extension cost in Cornwall?
- Build costs in Cornwall typically run from around £2,200 to £3,200 per square metre for a good-quality single-storey extension, more for kitchen-grade fit-out or complex glazing. We give a realistic budget before drawings start, not after.
Other services in Carbis Bay
Nearby places we cover