North Cornwall · TR5
Extensions for Goonbell (TR5)
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. Goonbell sits in North Cornwall, and that geography ends up in the drawings — Goonbell is a former mining settlement in the TR5 area, with granite terraces, chapel buildings and industrial landscape character still visible, with a building stock that leans toward post-war estates and granite terraces.
Goonbell sits in North Cornwall — covering TR5 from St Agnes, Mount Hawke, Trevellas outward.
- Cornish Mining World Heritage Site
- Rural / open-countryside policy area
- ✓ One studio — design, planning and build under one roof
- ✓ Local to North Cornwall — not a national franchise
- ✓ Measured-survey accuracy from day one
- ✓ Free first site visit, no obligation
Our process
How a Goonbell 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 proof — We typically have one or two extension jobs live in the TR5 area at any time, so the local planning officers know our drawings on sight.
Get a free feasibility viewWhat we focus on
Extensions considerations specific to Goonbell.
01
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
02
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.
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.
04
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
Local context
Why Goonbell is its own job.
In Goonbell the planning picture is specific: mining heritage, old plot widths and traditional materials make proportion and detailing more important than generic extension templates. For extension specifically, the wider area forms part of the Cornish Mining World Heritage Site, which adds a heritage assessment layer to most material changes; Cornwall Council's Local Plan applies tighter tests to isolated rural dwellings here, so design rationale and policy fit need to be set out clearly from the outset. That local reading is what makes a Goonbell (TR5) project different from a generic Cornwall scheme — and is the whole reason we work this way. On post-war estates in particular — the kind you'll also find toward Mithian — the extension brief always has to read the existing fabric first.
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.
Local watch-list
Goonbell-specific issues we screen on the first visit.
Watch #1
World Heritage Site assessment on changes visible in the mining landscape
Watch #2
Tighter Local Plan tests on isolated rural dwellings
Goonbell is part of St Agnes
Goonbell sits inside the St Agnes catchment — we cover both as one extension territory.
See Extensions in St Agnes →Local fabric
One TR5 studio, one extension job — start to finish.
Building stock
Across Goonbell (TR5) we work on miners cottages, granite terraces, chapel conversions, workers cottages, post-war estates. Each stock type drives a different extension response — post-war estates in particular needs careful detailing here.
Parish & policy
Goonbell sits in the parish of Goonbell, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR5 from our studio, with regular extension jobs also running in St Agnes, Mount Hawke, Trevellas. Most Goonbell site visits get booked within the same week.
Can you handle both planning and build in Goonbell?
Yes — design, planning, building regs and full construction run under one roof. For clients with an existing Goonbell builder we can stop at a tender-ready Full Plans pack instead.
Request a free visitWho this is for
Goonbell runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every extension enquiry from the use-class up.
FAQs
Goonbell Extensions — local questions answered.
- How much does an extension cost in Goonbell?
- 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. In Goonbell specifically, we'd start by checking the latest parish-level planning history before committing to a direction.
- Can you handle the build as well as the design?
- Yes — that's the whole point of the studio. One contract, one point of contact, no finger-pointing between architect and builder when something needs a decision on site.
- What about the Party Wall Act?
- If you share a wall with a neighbour or build close to a boundary, the Act applies. We flag it early, recommend a surveyor and keep the programme aligned with the notice period.
- 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.
Other services in Goonbell
Nearby places we cover
Every Goonbell extension we work on is treated as a TR5 job in its own right — local fabric, local policy, local builders.