East Cornwall · PL12
Granny annexes in Saltash — self-contained living, done well
A granny annexe in Saltash 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. The way we approach extension in Saltash starts with a measured walk-round — Saltash is the gateway town to Cornwall over the Tamar, with the Royal Albert Bridge, a steep medieval main street and a strong Plymouth commuter demand for housing, with a building stock that leans toward post-war estates at Latchbrook and Pillmere and medieval Fore Street terraces.
Saltash sits in East Cornwall — covering PL12 from Torpoint, Landrake, St Mellion outward.
- Conservation Area
- Coastal exposure zone
- ✓ Attached annexe: £75k–£110k built
- ✓ Detached garden annexe: £95k–£140k
- ✓ Ancillary use planning included
- ✓ Self-contained services throughout
Local watch-list
The PL12 constraints that shape a extension brief.
Watch #1
Conservation Area material and fenestration controls in central Saltash
Watch #2
Coastal exposure driving fixing, render and joinery spec
Who this is for
Saltash 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 context
Why Saltash is its own job.
In Saltash the planning picture is specific: conservation Area covers the historic Fore Street and waterfront. Tamar Bridge crossing and proximity to Plymouth shape edge-of-town residential growth significantly. For extension specifically, parts of Saltash sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; coastal salt-laden air around Saltash drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure. That local reading is what makes a Saltash (PL12) project different from a generic Cornwall scheme — and is the whole reason we work this way. On post-war estates at Latchbrook and Pillmere in particular — the kind you'll also find toward Callington — 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.
What we focus on
Extensions considerations specific to Saltash.
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.
Our process
How a Saltash 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
Saltash Extensions — local questions answered.
- Do I need planning permission for a granny annexe in Saltash?
- 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 Saltash?
- £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.
- 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. In Saltash specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- 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.
Saltash is the hub for these neighbourhoods
We run extensions across Saltash and the surrounding PL12 neighbourhoods — same studio, same site team.
- Hatt
PL12
- Landrake
PL12
- Tideford
PL12
- St Germans
PL12
- Pillaton
PL12
- Cargreen
PL12
- St Mellion
PL12
Local proof — Most Saltash homeowners come to us after a extension quote elsewhere felt vague on planning — we lead with feasibility instead.
Get a free feasibility viewOther services in Saltash
Nearby places we cover
Local neighbourhoods in Saltash
A Saltash granny annexe is 50% design, 50% planning wording — get the ancillary-use case right and everything downstream is straightforward.
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