Lizard Peninsula · TR12
Loft Conversions in Goonhilly
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. The Goonhilly version of this work has its own character — Goonhilly is a moorland-edge hamlet in the TR12 area, where exposed weather, narrow lanes and rural character set the brief, with a building stock that leans toward isolated houses and small rural infill.
Goonhilly sits in Lizard Peninsula — covering TR12 from St Keverne, Truro, St Austell outward.
- Cornwall AONB
- Rural / open-countryside policy area
- ✓ Local to Lizard Peninsula — not a national franchise
- ✓ Same team on paper as on site
- ✓ Fixed-fee planning packages, no surprise invoices
- ✓ Measured-survey accuracy from day one
Local watch-list
Local snags worth knowing before drawing a Goonhilly loft conversion.
Watch #1
AONB landscape-impact scrutiny on visible elevations
Watch #2
Tighter Local Plan tests on isolated rural dwellings
Who this is for
Goonhilly 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 Goonhilly is its own job.
Rural policy, landscape impact and services such as drainage are usually the key constraints, especially outside settlement boundaries. For loft conversion specifically, 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; 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 Goonhilly job runs as a TR12-specific piece of work — local policy, local fabric, local builders. Most of our loft conversion work in Goonhilly lands on isolated houses, with detailing that has to nod to the wider Truro streetscape.
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 Goonhilly.
01
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.
02
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.
03
Stairs eat space — a loft conversion lives or dies by where the new staircase lands and what it costs you on the floor below.
04
Cornish slate roofs come in a huge range of pitches — anything below a 30° pitch struggles to give usable headroom without raising the ridge.
Our process
How a Goonhilly 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
Goonhilly Loft Conversions — local questions answered.
- 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. In Goonhilly specifically, we'd start by checking AONB landscape sensitivity before committing to a direction.
- 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.
- Will I have enough headroom?
- We need a minimum 2.2 metres ridge-to-joist before alterations to make a usable conversion straightforward. Less than that and we'd consider raising the ridge, which is a planning conversation, not a permitted development one.
- 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.
Goonhilly is part of St Keverne
Goonhilly sits inside the St Keverne catchment — we cover both as one loft conversion territory.
See Loft Conversions in St Keverne →Local proof — Most Goonhilly homeowners come to us after a loft conversion quote elsewhere felt vague on planning — we lead with feasibility instead.
Get a free feasibility viewOther services in Goonhilly
Nearby places we cover
If you're considering a loft conversion project in the TR12 area, our deep understanding of Goonhilly's architectural character can help navigate the process smoothly.