Roseland · TR2
Hip-to-gable loft conversions in St Mawes — the extra metres explained
Hip-to-gable is the most misunderstood loft type in St Mawes. On a semi-detached with a hipped roof, extending the hip out to a vertical gable adds around 8–12m³ of usable volume — often the difference between a poky guest room and a proper master with en-suite. Combined with a rear dormer, it's the highest-yield loft move you can make in TR2. A well-designed loft conversion adds a bedroom, an en-suite and useful storage to homes that were never built with the upper floor in mind — usually inside permitted development and almost always cheaper per square metre than extending sideways. St Mawes sits in Roseland, and that geography ends up in the drawings — St Mawes sits on the Roseland Peninsula opposite Falmouth across the Carrick Roads, with a Henrician castle, ferry harbour and one of the highest property value markets in Cornwall, with a building stock that leans toward modern architect-designed coastal homes and Victorian villas.
St Mawes sits in Roseland — covering TR2 from St Just in Roseland, Portscatho, Gerrans outward.
- Conservation Area
- Cornwall AONB
- Coastal exposure zone
- Rural / open-countryside policy area
- ✓ Adds 8–12m³ of usable volume
- ✓ Best combined with a rear dormer
- ✓ Cost: £65k–£95k built
- ✓ PD on semi/detached outside Conservation Areas
Local watch-list
Common St Mawes pitfalls we plan around.
Watch #1
Conservation Area material and fenestration controls in central St Mawes
Watch #2
AONB landscape-impact scrutiny on visible elevations
Watch #3
Coastal exposure driving fixing, render and joinery spec
Watch #4
Tighter Local Plan tests on isolated rural dwellings
Who this is for
St Mawes runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every loft conversion enquiry from the use-class up.
Local context
Why St Mawes is its own job.
In St Mawes the planning picture is specific: conservation Area covers the seafront and harbour; AONB and Heritage Coast across the peninsula. Tight policy resistance to second-home expansion in some Roseland parishes. For loft conversion specifically, parts of St Mawes 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 St Mawes 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. That local reading is what makes a St Mawes (TR2) project different from a generic Cornwall scheme — and is the whole reason we work this way. On modern architect-designed coastal homes in particular — the kind you'll also find toward St Just in Roseland — the loft conversion brief always has to read the existing fabric first.
Planning note
Most Cornish loft conversions are permitted development — but a Certificate of Lawfulness is worth the extra week and small fee for resale protection.
What we focus on
Loft Conversions considerations specific to St Mawes.
01
Stairs eat space — a loft conversion lives or dies by where the new staircase lands and what it costs you on the floor below.
02
Cornish slate roofs come in a huge range of pitches — anything below a 30° pitch struggles to give usable headroom without raising the ridge.
03
Permitted development volume allowances are 40 cubic metres on a terrace and 50 on a detached or semi — but rear dormers in Conservation Areas often need full planning.
04
Building regs require minimum 2.0 metre headroom over the stairs and 30-minute fire protection on the existing stair enclosure — both shape the design.
Our process
How a St Mawes loft conversion project runs.
Step 1
Feasibility
Roof, headroom, stair landing and structural assessment.
Step 2
Design
Layout options that respect the staircase, headroom and bathroom positioning.
Step 3
Approvals
Planning or permitted development confirmation, plus building regs.
Step 4
Build
Sequenced to keep the family living downstairs throughout most of the work.
Step 5
Handover
Finish, snag, certify, hand over the keys.
Loft conversions typically run six to eighteen weeks on site depending on type, with four to eight weeks of design and approvals beforehand.
FAQs
St Mawes Loft Conversions — local questions answered.
- What's a hip-to-gable loft conversion?
- The sloping "hip" end of the roof is rebuilt as a vertical gable wall, adding roughly 8–12m³ of habitable volume. Almost always combined with a rear dormer.
- Do I need planning for a hip-to-gable in St Mawes?
- Yes — Conservation Area removes hip-to-gable from PD entirely.
- How much does a hip-to-gable + dormer cost in St Mawes?
- £65k–£95k for the combined works, including new stair, master bedroom and en-suite. Timber cladding on the new gable is popular and adds ~£4k.
- How long does a loft conversion take?
- Allow six to ten weeks on site for a Velux conversion, eight to fourteen weeks for a dormer, twelve to eighteen weeks for hip-to-gable. Add four to eight weeks for design and regs beforehand. In St Mawes specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- Will it add value?
- An extra bedroom and bathroom typically adds noticeably more value than the build cost in most Cornish markets — but the value matters less than the daily use you'll get from the space.
- How much does a loft conversion cost?
- A simple Velux conversion starts around £30,000 in Cornwall; a rear dormer with en-suite typically runs £45,000 to £65,000; hip-to-gable and mansards more. Stair location and bathroom complexity drive most of the cost.
St Mawes is the hub for these neighbourhoods
We run loft conversions across St Mawes and the surrounding TR2 neighbourhoods — same studio, same site team.
Local proof — Most St Mawes homeowners come to us after a loft conversion quote elsewhere felt vague on planning — we lead with feasibility instead.
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Nearby places we cover
Local neighbourhoods in St Mawes
A St Mawes hip-to-gable only makes sense on properties with a hipped side roof — but where it applies, no other loft type gives more usable space for the money.
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