West Cornwall · TR20 · Cornwall Council West
House Extensions in Goldsithney
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. A Goldsithney brief starts on the street, not the screen — Goldsithney is a small linear village on the B3280 inland from Marazion — and home to the Trademark Designs studio, so we know its lanes, water table and planning history personally, with a building stock that leans toward Victorian semis and modern infill and barn conversions.
Goldsithney sits in West Cornwall — just off the A30; covering TR20 from Marazion, Perranuthnoe outward.
- Rural / open-countryside policy area
- ✓Fixed-fee planning packages, no surprise invoices
- ✓Measured-survey accuracy from day one
- ✓One studio — design, planning and build under one roof
- ✓Local to West Cornwall — not a national franchise
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Free Goldsithney feasibility call
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Local watch-list
What usually catches extension projects out in Goldsithney.
Watch #1
Local Plan tests on isolated dwellings, plus lane access for plant and deliveries around Goldsithney
Watch #2
Party Wall notices and shallow roof voids typical of traditional granite cottages in the TR20 district
Who this is for
In Goldsithney the extension brief is almost always a private homeowner improving a forever home — so we lead with feasibility and long-term value, not show-home rhetoric.
Scope
The parts of the job we can take on in Goldsithney
Clients in Goldsithney take different slices of this list, and that is deliberate.
Full design and build
One contract from first sketch to handover, with the same team on paper and on site.
Building regulation drawings
Full Plans sets with sections, construction notes and coordinated structural information.
Planning application drawings
Existing and proposed plans, elevations, site and block plans drawn to validation standard.
Construction and technical drawings
1:10 and 1:20 details for the parts of the job builders normally have to guess at.
Structural coordination
Calculations coordinated with the drawings so building control sees one consistent story.
Who this is for
What we can genuinely back up in Goldsithney
- Drawings, planning and building regulations are all produced in-house, so a extension enquiry does not get passed between firms.
- Design and build are offered from the same studio, which means the person answering your Goldsithney questions has seen the detail built.
- Applications for Goldsithney are handled through Cornwall Council, with Truro the nearest planning office we deal with regularly.
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.
Keep reading
Other work we do around Goldsithney
Goldsithney is covered from our Marazion 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.
Page purpose
Drawings only, or drawings through to handover in Goldsithney?
Both routes are open on a TR20 project, and the honest answer depends on whether you already have a builder you trust. Plenty of Goldsithney 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 TR20 scope, not as one opaque figure
Local context
Why Goldsithney is its own job.
Outside the Conservation Area but the village fringes border the AONB; Perranuthnoe parish policy applies. Infill and barn conversion proposals dominate the parish planning workload. For extension specifically, 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. So every Goldsithney job runs as a TR20-specific piece of work — local policy, local fabric, local builders. Most of our extension work in Goldsithney lands on Victorian semis, with detailing that has to nod to the wider Perranuthnoe streetscape.
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 Goldsithney.
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
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.
03
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
04
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
Quick check
Want a straight answer on whether your Goldsithney 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 Goldsithney and the TR20 area.
Our process
How a Goldsithney 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
Goldsithney Extensions — local questions answered.
- 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. In Goldsithney specifically, we'd start by checking the latest parish-level planning history before committing to a direction.
- 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.
- 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 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.
- We live in the house. Can a extension in Goldsithney 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 Goldsithney are often easier if you move out for a few weeks. We set that expectation at feasibility stage rather than halfway through.
Goldsithney is part of Marazion
Goldsithney sits inside the Marazion catchment — we cover both as one extension territory.
See Extensions in Marazion →Local proof — Most Goldsithney extension clients we work with are second-time builders — they've seen the templated approach fail once already.
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Nearby places we cover
In short: take the drawings and run your own build in Goldsithney, or keep it under one contract. Both routes start the same way. Lane access and rural policy tests shape what is realistic on an isolated plot.
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