East Cornwall · PL18 · Cornwall Council East
Extensions for Calstock (PL18)
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 Calstock starts with a measured walk-round — Calstock is a creekside settlement in the PL18 area, with waterside homes, wooded valleys and narrow-lane access shaping the brief, with a building stock that leans toward creekside cottages and boat sheds.
Calstock sits in East Cornwall — just off the A38; covering PL18 from Callington, Stoke Climsland, Linkinhorne outward.
- Conservation Area
- Cornish Mining World Heritage Site
- ✓Same team on paper as on site
- ✓Fixed-fee planning packages, no surprise invoices
- ✓Local to East Cornwall — not a national franchise
- ✓One studio — design, planning and build under one roof
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Free Calstock feasibility call
Tell us about your extension. We reply within 1 working day — no obligation.
Page purpose
Drawings only, or drawings through to handover in Calstock?
Both routes are open on a PL18 project, and the honest answer depends on whether you already have a builder you trust. Plenty of Calstock clients take the drawings, tender them locally, then come back to us for the build if the numbers do not stack up.
- Route one: feasibility, planning and a tender-ready technical pack
- Route two: the same pack, then the build under one contract
- Either way the survey and feasibility work is identical, so the decision can wait
- Fees quoted per stage against the PL18 scope, not as one opaque figure
Scope
Scope options for Calstock clients
Not every project needs every stage. On a Calstock job we scope to what the site and the consent route actually require.
Planning application drawings
Existing and proposed plans, elevations, site and block plans drawn to validation standard.
Measured survey
An accurate record of what is actually there, which is where most avoidable cost is removed.
Heritage and design statements
Written justification where designation makes the design case as important as the drawing.
Structural coordination
Calculations coordinated with the drawings so building control sees one consistent story.
Full design and build
One contract from first sketch to handover, with the same team on paper and on site.
Local watch-list
The PL18 constraints that shape a extension brief.
Watch #1
Conservation Area controls on materials, window proportions and roof form through central Calstock
Watch #2
World Heritage Site heritage assessment where changes are visible in the mining landscape
Watch #3
Party Wall notices and shallow roof voids typical of creekside cottages in the PL18 district
Who this is for
Straight facts about working with us here
- Applications for Calstock are handled through Cornwall Council, with Liskeard the nearest planning office we deal with regularly.
- Designated-area work is routine here, so heritage and landscape statements are produced alongside the drawings rather than outsourced.
- Drawings, planning and building regulations are all produced in-house, so a extension enquiry does not get passed between firms.
Planning rules change and every site is different. For the final position on your address, check with Cornwall Council as the local planning authority or the Planning Portal.
What we focus on
Extensions considerations specific to Calstock.
01
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
02
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
03
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
04
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.
Quick check
Want a straight answer on whether your Calstock project is worth pursuing?
Send a few details — we'll come back within 1 working day with a plain-English view on planning risk, likely cost band and whether it's a project we'd take on.
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Get a free feasibility view
For projects in Calstock and the PL18 area.
Local context
Why Calstock is its own job.
In Calstock the planning picture is specific: creekside ecology, flood risk, trees and views across the water often matter as much as the building form itself. For extension specifically, parts of Calstock 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. That local reading is what makes a Calstock (PL18) project different from a generic Cornwall scheme — and is the whole reason we work this way. On creekside cottages in particular — the kind you'll also find toward Gunnislake — 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.
Our process
How a Calstock 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
Calstock Extensions — local questions answered.
- 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 Calstock specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- We live in the house. Can a extension in Calstock be done while we stay put?
- Usually yes for single-storey and rear work, with a temporary kitchen or bathroom arrangement agreed before the start. Whole-house remodels and roof work in Calstock are often easier if you move out for a few weeks. We set that expectation at feasibility stage rather than halfway through.
- 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.
- 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.
Calstock is part of Callington
Calstock sits inside the Callington catchment — we cover both as one extension territory.
See Extensions in Callington →Keep reading
Where to go next from Calstock
Calstock is covered from our Callington run. Being a smaller place, the local detail matters more than the headline policy: lane access, neighbour proximity and what the immediate street already looks like.
Other services in Calstock
Nearby places we cover
A Calstock extension can be bought in stages, and most clients decide the build route after feasibility. Applications are dealt with through Cornwall Council, with Liskeard the office we deal with most for PL18.
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