Lizard Peninsula · TR12 · Cornwall Council West
Garage conversions in Mullion — habitable space from an underused garage
Most Mullion garages haven't taken a car in a decade — they're storage boxes with poor insulation and a big-up-and-over door. Converting to a proper habitable room gives 12–18m² of new floor space at £18k–£32k, which is the cheapest extra floor you'll ever add in TR12. Cornish housing stock is brilliant and infuriating in equal measure. We renovate cottages, farmhouses, mid-century homes and post-war estates — opening up layouts, fixing damp, adding light and bringing the property up to a standard worth living in. Reading Mullion on the ground is half of the renovation job — Mullion is the largest village on the Lizard Peninsula, AONB-designated, with a fifteenth-century church, a working cove and the highest concentration of period housing on the peninsula, with a building stock that leans toward Edwardian guesthouses and modern AONB-sensitive replacement dwellings.
Mullion sits in Lizard Peninsula — just off the A394; covering TR12 from Mawgan, Ruan Minor, The Lizard outward.
- Conservation Area
- Cornwall AONB
- Coastal exposure zone
- Rural / open-countryside policy area
- ✓Typical Mullion garage conversion: £18k–£32k
- ✓12–18m² new habitable floor
- ✓Building regs sign-off included
- ✓Usually permitted development
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Free Mullion feasibility call
Tell us about your renovation. We reply within 1 working day — no obligation.
Local watch-list
Mullion-specific issues we screen on the first visit.
Watch #1
Conservation Area controls on materials, window proportions and roof form through central Mullion
Watch #2
AONB landscape-impact testing on anything read in long views across Lizard Peninsula
Watch #3
Exposure detailing on granite cottages around the church — fixings, render systems and joinery specified for salt-laden air
Watch #4
Local Plan tests on isolated dwellings, plus lane access for plant and deliveries around Mullion
Who this is for
In Mullion the renovation 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 Mullion
These stages can be bought separately. Most TR12 projects use three of them.
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.
Construction and technical drawings
1:10 and 1:20 details for the parts of the job builders normally have to guess at.
Building regulation drawings
Full Plans sets with sections, construction notes and coordinated structural information.
Who this is for
What we can genuinely back up in Mullion
- Design and build are offered from the same studio, which means the person answering your Mullion questions has seen the detail built.
- Drawings, planning and building regulations are all produced in-house, so a renovation enquiry does not get passed between firms.
- Designated-area work is routine here, so heritage and landscape statements are produced alongside the drawings rather than outsourced.
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 Mullion
We cover Mullion and the wider TR12 district directly. Renovations enquiries here are common enough that we know the constraints before the first visit.
Page purpose
Drawings only, or drawings through to handover in Mullion?
Both routes are open on a TR12 project, and the honest answer depends on whether you already have a builder you trust. Plenty of Mullion 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 TR12 scope, not as one opaque figure
Local context
Why Mullion is its own job.
Around Mullion (TR12), mullion Conservation Area covers the village centre; the wider parish is entirely within the AONB and includes Heritage Coast designation. Cliff-edge and coastal margin sites face the strictest controls in West Cornwall. For renovation specifically, parts of Mullion 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 Mullion drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure; 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. Reading Mullion properly up front saves more time than any drawing tool ever will. Most of our renovation work in Mullion lands on Edwardian guesthouses, with detailing that has to nod to the wider Mawgan streetscape. On older stock, the practical constraint is usually joinery, render and roof line rather than the extension itself. We draw those details out early so a renovation submission is not sent back for missing information. Confirm listing status with the local planning authority before assuming permitted development. Exposure is the real design driver near the water: wind-driven rain, salt and driving damp push detailing towards better weathering, sheltered openings and robust fixings. Where an AONB or coastal policy applies, visual impact usually carries more weight than size.
Planning note
Most Cornish renovations don't need planning — but listed status, curtilage listing, Conservation Area designation and material changes can all change that picture.
What we focus on
Renovations considerations specific to Mullion.
01
Damp in Cornish cottages is usually a moisture management problem, not a chemical injection problem — fixing the cause is cheaper long term than treating the symptom.
02
Listed and curtilage-listed properties need Listed Building Consent for many internal alterations that wouldn't normally need approval.
03
Asbestos surveys are standard for anything pre-2000 — we factor a survey into the programme before stripping out begins.
04
Older Cornish properties are often built with cob, rubble or solid granite — modern insulation strategies that work in cavity walls cause damp problems in solid construction. Breathable build-ups matter.
Quick check
Want a straight answer on whether your Mullion 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 Mullion and the TR12 area.
Our process
How a Mullion renovation project runs.
Step 1
Survey
Measured survey, condition assessment, services check and listed status review.
Step 2
Design
Layout options, material strategy and a clear list of what stays and what changes.
Step 3
Approvals
Listed Building Consent and building regulations as needed.
Step 4
Strip-out and works
Carefully sequenced demolition, structural works and rebuild.
Step 5
Finish and handover
Joinery, decoration, snagging and documentation pack.
Whole-house renovations typically run six to fourteen months on site; partial remodels two to four months.
FAQs
Mullion Renovations — local questions answered.
- Do I need planning permission for a garage conversion in Mullion?
- Usually no — internal conversions of an existing attached garage are permitted development. Facade changes may need consent though.
- How much does a garage conversion cost in Mullion?
- £18k–£32k for a standard single garage (12–18m²), including insulation, new floor build-up, replacement front wall and one window. Building regs sign-off included.
- Will a garage conversion affect house value in Mullion?
- Positive on most TR12 stock, provided at least one parking space is retained. Loss of the last parking space can knock 2–4% off value.
- What about damp and old walls?
- We assess the cause first — usually rising damp myths, blocked vents, hard cement renders trapping moisture, or roofs needing attention. A breathable repair strategy fixes most of it without chemical intervention. In Mullion specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- How long does a renovation take?
- Single rooms in weeks, kitchens in two to three months, whole-house renovations in six to fourteen months depending on size and listed status.
- Can I live in the house during the work?
- Sometimes yes, often no. Single-room remodels and phased work can be liveable; whole-house renovations involving rewires, replumbing or floor lifting almost never are. We're honest about this at the brief.
Local proof — Most Mullion homeowners come to us after a renovation quote elsewhere felt vague on planning — we lead with feasibility instead.
Get a free feasibility viewOther services in Mullion
Nearby places we cover
A Mullion garage conversion is the cheapest £/m² route to more living space — provided the existing slab and lintel are up to it. We survey both before any fee.
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