Key Takeaway
Three main loft conversion types, three different costs, three different planning outcomes. This guide explains which type suits your Hampshire property and what each one involves.
When Hampshire homeowners start researching loft conversions, they often encounter unfamiliar terminology: dormers, Velux, hip-to-gable, mansard. Each term refers to a different approach to converting unused roof space into a habitable room — with different implications for planning permission, build cost, and the amount of usable space created.
This guide explains the three most common conversion types across Hampshire — rear dormer, Velux/roof light, and hip-to-gable — and helps you understand which approach is most suitable for your specific property.
Velux / Roof Light Conversion: The Simplest Approach
A Velux conversion installs roof windows into the existing roof slope without altering the external roofline. The ceiling inside follows the slope of the roof, which limits head height in parts of the room but creates a characterful, light-filled space.
Planning
Velux conversions are the only loft conversion type that requires no planning permission in virtually all cases — including conservation areas. Installing roof windows does not change the external profile of the roof and is permitted development for almost every property type. Building regulations approval is still required.
Best suited for
- Properties with steep roof pitches (35° or more) providing good natural head height
- Conservation area properties where a dormer might be refused
- Projects where budget is the primary constraint
- Homeowners wanting the quickest route to a habitable loft room
Typical build cost in Hampshire
£20,000–£40,000 depending on specification. Hampshire Build design from £1,950+VAT.
Rear Dormer Conversion: The Most Popular Choice
A rear dormer extends vertically from the rear roof slope, breaking out of the roofline to create a box-shaped structure with a flat or pitched roof. This provides full head height throughout the loft room and the space for a proper en-suite bathroom — something a Velux conversion often cannot accommodate.
Planning
Most rear dormers in Hampshire fall within Permitted Development rights, meaning no planning application is required. The national rules allow rear dormers up to 40m³ on semi-detached and terraced properties, and up to 50m³ on detached properties, subject to conditions about height, materials, and position. Properties in conservation areas and those subject to Article 4 Directions may require planning permission.
Best suited for
- Semi-detached and terraced houses with rear slopes
- Properties where a full en-suite bathroom is required
- Homeowners wanting maximum head height throughout the loft room
- Any Hampshire property type where the roof pitch is too shallow for a comfortable Velux conversion
Typical build cost in Hampshire
£45,000–£70,000. Hampshire Build design from £1,950+VAT.
Hip-to-Gable Conversion: Maximum Space on Hipped Roofs
A hip-to-gable conversion rebuilds the sloping hip end of the roof as a vertical gable wall, extending the ridge and significantly increasing the usable floor area in the loft. On a typical Hampshire 1970s detached house, this can add 15–20m² of usable space compared to a dormer-only approach — the difference between a modest study and a full double bedroom with en-suite.
Planning
Hip-to-gable conversions always require planning permission because they change the external form of the roof. Hampshire's local planning authorities — Winchester City Council, Basingstoke and Deane Borough Council, Southampton City Council, and Test Valley Borough Council — are generally receptive to well-designed proposals on appropriate property types. Hampshire Build manages the planning application process.
Best suited for
- Detached and end-of-terrace properties with hipped roofs
- The large 1960s–80s estates across Basingstoke, Andover, Fareham, and Southampton suburbs
- Homeowners wanting maximum floor space from the loft conversion
- Properties where the loft space is currently very restricted due to the hipped roof
Typical build cost in Hampshire
£50,000–£85,000. Often combined with a rear dormer for £65,000–£95,000. Hampshire Build design from £1,950+VAT.
Which Type Is Right for Your Property?
The right choice depends on four factors:
- Your roof structure: Does your property have a gable or hipped roof? What is the roof pitch? How much existing head height is there?
- Your planning position: Is the property in a conservation area? Has it had previous extensions that may have used the PD allowance?
- Your goals: Do you need a full en-suite bathroom? Is maximising floor space the priority?
- Your budget: Velux conversions cost significantly less than dormers, which cost less than hip-to-gable combinations.
Hampshire Build assesses all of these factors at the initial complimentary consultation. We will tell you which conversion type is feasible for your specific property, what the planning position is, and what it will cost to design — all at no charge and with no obligation.
Location-Specific Pages
Hampshire Build has created dedicated loft conversion pages for the key areas we serve:
- Loft conversion design in Winchester — including conservation area advice and the common property types in Stanmore, Oliver's Battery, and Kings Worthy
- Loft conversion design in Basingstoke — including the extensive hip-to-gable opportunities across Popley, Chineham, and Kempshott
- Loft conversion design in Southampton — covering Victorian terraces in Shirley and Portswood through to inter-war semis in Bassett and Bitterne Park
- Loft conversion design in Andover — including the Test Valley Borough Council planning process
We also have specific guidance on dormer conversions, Velux conversions, and hip-to-gable conversions across Hampshire.