South Cornwall · TR11
Mylor Harbour extension — feasibility first, drawings second
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. Anchor any Mylor Harbour extension in the local fabric and the rest follows — Mylor Harbour is a creekside settlement in the TR11 area, with waterside homes, wooded valleys and narrow-lane access shaping the brief, with a building stock that leans toward detached houses and waterside homes.
Mylor Harbour sits in South Cornwall — covering TR11 from Mylor Bridge, Truro, St Austell outward.
- Conservation Area
- Cornwall AONB
- Coastal exposure zone
- ✓ Plain-English feasibility before any drawings
- ✓ 30+ years of Cornwall Council approvals
- ✓ Conservation Area experience built into the fee
- ✓ Cornwall Council regulars across every sub-area
Who this is for
Mylor Harbour runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every extension enquiry from the use-class up.
Local watch-list
Mylor Harbour-specific issues we screen on the first visit.
Watch #1
Conservation Area material and fenestration controls in central Mylor Harbour
Watch #2
AONB landscape-impact scrutiny on visible elevations
Watch #3
Coastal exposure driving fixing, render and joinery spec
Local proof — Our South Cornwall workload means a Mylor Harbour extension project never has to wait for an out-of-county team to drive down.
Get a free feasibility viewFAQs
Mylor Harbour Extensions — local questions answered.
- 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. In Mylor Harbour specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- 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.
- 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 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.
- 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.
Local context
Why Mylor Harbour is its own job.
Locally, creekside ecology, flood risk, trees and views across the water often matter as much as the building form itself. For extension specifically, parts of Mylor Harbour sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; 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 Mylor Harbour drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure. Which is why we scope Mylor Harbour projects parish-up, not template-down — the TR11 context shapes the design from day one. Whether the project is on detached houses in the centre or further out toward Mylor Bridge, 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 Mylor Harbour.
01
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.
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
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
04
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
Our process
How a Mylor Harbour 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
Choosing a extension team that actually knows TR11.
Building stock
Across Mylor Harbour (TR11) we work on creekside cottages, detached houses, boat sheds, converted barns, waterside homes. Each stock type drives a different extension response — detached houses in particular needs careful detailing here.
Parish & policy
Mylor Harbour sits in the parish of Mylor Harbour, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR11 from our studio, with regular extension jobs also running in Mylor Bridge, Truro, St Austell. Most Mylor Harbour site visits get booked within the same week.
What does a first Mylor Harbour consultation cost?
Nothing. We come to the property, walk the site, talk through what works on a TR11 plot and follow up with a written feasibility note inside a week — no obligation either way.
Request a free visitMylor Harbour is part of Mylor Bridge
Mylor Harbour sits inside the Mylor Bridge catchment — we cover both as one extension territory.
See Extensions in Mylor Bridge →Other services in Mylor Harbour
Nearby places we cover
A extension in Mylor Harbour stands or falls on how well it reads the street — we treat that as the design brief, not an afterthought.