West Cornwall · TR27 · Cornwall Council West
Granny annexes in Hayle — self-contained living, done well
A granny annexe in Hayle is either an attached extension with a separate entrance, a garden building with independent services, or a garage conversion. Cornwall Council treats all three under the "ancillary residential" test — meaning they must remain connected to the main dwelling's planning use. Get the planning wording right and the design opens up. 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. On a Hayle site, the brief always meets the place — Hayle is a former industrial port and Cornish Mining World Heritage town spread along the Hayle estuary, with the three-mile dunes of Hayle Towans on its northern shore, with a building stock that leans toward dune-edge bungalows and industrial workers' terraces.
Hayle sits in West Cornwall — just off the A30; with Truro the closest city; 3 miles from St Ives.
- Conservation Area
- Cornish Mining World Heritage Site
- Coastal exposure zone
- ✓ Attached annexe: £75k–£110k built
- ✓ Detached garden annexe: £95k–£140k
- ✓ Ancillary use planning included
- ✓ Self-contained services throughout
Local proof — Our West Cornwall workload means a Hayle extension project never has to wait for an out-of-county team to drive down.
Get a free feasibility viewLocal context
Why Hayle is its own job.
The planning backdrop in West Cornwall is real, not abstract: hayle's World Heritage Site status applies to the harbour, foundry and Copperhouse areas — alterations and infill within those zones face heritage assessment. North Quay and Carnsew development pressure has shaped a strong local design code on materials and massing. For extension specifically, parts of Hayle sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; the wider area forms part of the Cornish Mining World Heritage Site, which adds a heritage assessment layer to most material changes; coastal salt-laden air around Hayle drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure. Treat the TR27 parish brief as the design brief and the Hayle application has somewhere to land. Whether the project is on dune-edge bungalows in the centre or further out toward Lelant, the extension response is locally tuned.
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 Hayle.
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
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
04
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
Our process
How a Hayle 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.
Local fabric
Why Hayle homeowners pick a local studio for extension.
Building stock
Across Hayle (TR27) we work on industrial workers' terraces, Foundry-era cottages, Victorian semis, modern estates at Loggans, dune-edge bungalows. Each stock type drives a different extension response — dune-edge bungalows in particular needs careful detailing here.
Parish & policy
Hayle is its own town in West Cornwall, with planning history that's specific to the TR27 catchment.
Coverage
We cover TR27 from our studio, with regular extension jobs also running in St Ives, Lelant, Connor Downs. Most Hayle site visits get booked within the same week.
What does a first Hayle consultation cost?
Nothing. We come to the property, walk the site, talk through what works on a TR27 plot and follow up with a written feasibility note inside a week — no obligation either way.
Request a free visitRecent work nearby
Foundry Square shop-to-flat we ran kept industrial brick on the long elevation.
See more recent West Cornwall work →FAQs
Hayle Extensions — local questions answered.
- Do I need planning permission for a granny annexe in Hayle?
- Yes — annexes always need planning consent to establish ancillary residential use. Attached annexes go through householder; detached garden annexes need full planning.
- How much does a granny annexe cost in Hayle?
- £75k–£140k for a 30–55m² annexe with kitchenette, bedroom, bathroom and living area. Detached garden annexes cost 10–20% more than attached (utility runs and separate roof).
- Can we let out the annexe as a holiday let later?
- Only with a further change-of-use application. Ancillary consent explicitly ties the annexe to the main dwelling — subletting breaches that condition.
- 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 Hayle specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- 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 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.
Hayle is the hub for these neighbourhoods
We run extensions across Hayle and the surrounding TR27 neighbourhoods — same studio, same site team.
- Angarrack
TR27
- Phillack
TR27
- Connor Downs
TR27
- Gwinear
TR27
- Gwithian
TR27
- Godrevy
TR27
- Canonstown
TR27
- Leedstown
TR27
- Townshend
TR27
Other services in Hayle
Nearby places we cover
Local neighbourhoods in Hayle
A Hayle granny annexe is 50% design, 50% planning wording — get the ancillary-use case right and everything downstream is straightforward.
Design a granny annexe on your Hayle plot
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