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Loft Conversion Design & Planning
Transform your unused loft into a stunning bedroom, home office or playroom. Our architectural designers produce full planning drawings, building regulations packages and structural calculations for all types of loft conversion across Hampshire.
All Conversion Types
Velux to mansard
Full Design Package
Plans & calculations
Building Regs Compliant
Fire, stairs, insulation
20+ Years Experience
Residential specialists
Types of Loft Conversion
The right type depends on your roof shape, head height, budget and planning constraints. We'll advise you during your free feasibility check.
Velux (Rooflight)
The most affordable option — internal conversion with roof windows. No external alterations to the roofline, making it ideal where permitted development rights apply.
Best for: Homes with good existing head height
Dormer Loft Conversion
The most popular type in Hampshire. A box-shaped extension projects from the rear roof slope, creating full standing height and usable floor space across the loft.
Best for: Most family homes needing extra bedrooms
Hip-to-Gable
Converts the sloping hip end of a roof into a vertical gable wall, dramatically increasing the internal loft space. Often combined with a rear dormer.
Best for: Semi-detached and detached homes with hipped roofs
Mansard Conversion
The most extensive conversion, replacing a roof slope with a near-vertical wall and flat top. Creates the maximum possible space but always requires planning permission.
Best for: Properties needing maximum space, period homes
Is Your Loft Suitable?
Not every loft can be converted. Here's what we check during your free feasibility assessment.
Key Suitability Factors
Head Height
Minimum 2.2m from floor joist to ridge is ideal. Less than this and a dormer or mansard may be needed.
Roof Structure
Traditional cut timber roofs are easier to convert. Trussed roofs need structural engineer input.
Staircase Position
You need space for a compliant staircase — often taken from a landing or small bedroom.
Chimney Breast & Services
Central chimney breasts, water tanks and boiler flues may need relocating.
Planning & Building Regulations
Permitted Development
Many rear dormers and Velux conversions fall under PD rights — no planning application needed. Volume limits apply: 40m³ for terraced houses, 50m³ for detached/semi-detached.
When Planning is Required
Front-facing dormers, mansard conversions, hip-to-gable alterations, conservation areas and listed buildings all typically need full planning permission.
Building Regulations (Always Required)
Every loft conversion needs building regulations approval covering: structural integrity, fire escape routes, sound insulation, thermal insulation, staircase design and means of escape.
Fire Safety: Loft conversions create a 3-storey dwelling. Building regs require protected escape routes, fire doors, smoke detection and sometimes mains-powered interlinked alarms.
Loft Conversion Costs
Design fees and typical build costs to help you budget. Our design packages start from £1,350 + VAT.
Our Design Fees
Includes planning drawings, building regs package & structural calculations
Typical Build Costs
Build costs are approximate and vary by location, specification and access
Frequently Asked Questions
Loft conversions in Hampshire typically cost £40,000–£70,000 to build, depending on type and size. Dormer conversions are the most popular and affordable option. Our design packages start from £1,350+VAT for planning drawings and feasibility assessment.
Many loft conversions qualify under Permitted Development rights, provided they meet volume limits (40m³ for terraced, 50m³ for detached/semi-detached). Dormers facing a highway, conservation areas, or exceeding the existing roof height usually require planning permission.
The four main types are dormer (most popular, adds headroom), hip-to-gable (suits hipped roofs), mansard (maximum space but usually needs planning), and Velux/rooflight (simplest, no external changes). The best option depends on your roof structure and space requirements.
A typical loft conversion takes 6–10 weeks to build once design and planning are complete. The design and planning phase takes 8–12 weeks. Dormer conversions are generally faster than hip-to-gable or mansard conversions. We provide detailed timelines at the design stage.
Most lofts can be converted, but key factors include head height (minimum 2.2m at the ridge), roof pitch, chimney positions, and existing structural elements. We carry out a feasibility assessment to determine viability and recommend the best conversion type for your property.
Explore Related Services & Resources
From Our Portfolio
Helpful Guides
Loft Conversion Design Hampshire
Dedicated fixed-fee loft conversion design service page
Extension Cost Calculator
Get an instant cost estimate for your loft conversion
Extension Design Service
Fixed-fee planning drawings and building regs
Party Wall Notice Guide
Party wall requirements for loft conversions
Our Design Packages
Fixed-fee packages from £1,350 + VAT
We Serve Your Area
Ready to Convert Your Loft?
Book a free feasibility check. We'll assess your loft's suitability, advise on the best conversion type and provide a clear design fee quote.