Loft conversion drawings
With rising house prices and space at a premium, more homeowners are choosing to convert their underused attic space into valuable living areas. Whether you’re planning a new bedroom, home office, or even an en suite master suite, a loft conversion is one of the most cost-effective ways to add space and value to your home.
What Is a Loft Conversion?
A loft conversion is the process of transforming an empty or underused attic into a functional, habitable room. It can significantly increase a home’s floor space without the need to extend externally, making it ideal for urban or terraced properties.
Benefits of a Loft Conversion
• Adds living space without reducing garden size
• Increases property value (typically by 15–20%)
• Cheaper than moving to a larger home
• Quick to construct (typically 6–12 weeks)
• Can often be done under Permitted Development rights
Types of Loft Conversions in the UK
There are several main types of loft conversions, each suited to different house types and budgets:
1. Roof Light (Velux) Loft Conversion
Description: The simplest and most affordable type, it uses the existing roof space with the addition of Velux-style windows for natural light.
Pros:
• Minimal structural alteration
• Lower cost and faster construction
• Often within Permitted Development
Cons:
• Limited headroom
• May not suit all roof types or room uses
Best for: High-pitched roofs with plenty of existing space
2. Dormer Loft Conversion
Description: Adds a box-like structure to the rear or side of the roof, creating vertical walls and increased headroom and floor space.
Types of Dormers:
• Flat Roof Dormer: Maximises space—most common type
• Gable-Fronted Dormer: Adds a pitched roof over the dormer
• Hipped Dormer: Sloped sides, often used on detached homes
Pros:
• Increases usable floor space and natural light
• Popular and versatile
• Often falls under Permitted Development
Cons:
• Boxy appearance unless well designed
• May not suit front-facing elevations in conservation areas
Best for: Terraced and semi-detached houses
3. Hip-to-Gable Loft Conversion
Description: Converts the sloping hip of a roof (common in end-of-terrace or detached homes) into a vertical gable wall to increase internal volume.
Often combined with a rear dormer for even more space.
Pros:
• Substantial increase in headroom and floor space
• Better suited for creating larger rooms
Cons:
• Requires major structural alteration
• Almost always requires planning permission in conservation areas
Best for: End-of-terrace or detached homes with hipped roofs
4. Mansard Loft Conversion
Description: The most extensive type, it alters the entire slope of the roof to a near-vertical angle at the rear and sometimes front, often across the whole width of the house.
Pros:
• Maximum internal space and ceiling height
• Can be very aesthetically pleasing, especially on period homes
Cons:
• Most expensive and time-consuming
• Requires full planning permission
• Major structural work required
Best for: Homes in cities, terraces, or properties with planning flexibility
5. L-Shaped Dormer Conversion
Description: An extension of a standard dormer to form an L-shape over the main roof and rear projection, usually on Victorian or Edwardian terraces.
Pros:
• Can create multiple rooms or self-contained units
• Excellent use of space on extended properties
Cons:
• Design complexity
• May require planning permission depending on roof size
Best for: Houses with rear projections (outriggers)
Loft Conversion Suitability: Can My Loft Be Converted?
Key Factors to Consider:
• Head Height: Ideally, a minimum of 2.2 metres from the ceiling joist to the ridge.
• Roof Pitch and Structure: Traditional cut timber roofs are easier to convert than modern trussed roofs.
• Staircase Placement: Must allow for safe and accessible entry without compromising existing space.
• Chimney Stacks and Services: Can add complexity or limit design options.
• Structural Integrity: New floors and supports may be needed to comply with building regulations.
Planning Permission for Loft Conversions
Permitted Development Rights
Most loft conversions fall under Permitted Development (PD) if they meet criteria such as:
• Maximum volume increase:
• 40m³ for terraced houses
• 50m³ for detached/semi-detached houses
• No extensions beyond the roof plane facing the road
• Materials must be similar in appearance to the existing property
• No balconies or raised platforms
• Dormers must be set back at least 20cm from the eaves
When Planning Permission is Required
• Property is in a conservation area, AONB, or is a listed building
• Conversion involves altering the roof height or shape (e.g. mansards, hip-to-gable)
• Dormers face the street
• You exceed the PD volume allowance
Tip: Apply for a Lawful Development Certificate even if PD applies, to safeguard future resale or legal issues.
Loft Conversion Costs (2025 Estimates)
Rooflight / Velux: £20,000 - £35,000
Rear Dormer: £35,000 - £60,000
Hip-to-Gable: £45,000 - £70,000+
Mansard: £55,000 - £85,000+
L-Shaped Dormer: £50,000 - £80,000+
Factors Affecting Cost:
• Roof structure complexity
• Size and layout
• Internal finishes and fittings
• Staircase alterations
• Professional and legal fees
Building Regulations for Loft Conversions
Regardless of planning permission, all loft conversions must comply with Building Regulations, including:
• Structural safety (floors, beams, supports)
• Fire safety (fire-resistant doors, escape routes, alarms)
• Insulation and ventilation
• Staircase design (steepness, head clearance)
• Soundproofing
• Windows and natural light (minimum 1/20th of the floor area)
You can use your local authority’s building control or an approved private inspector. Expect site visits at key construction stages.
Professional Services You May Need
• Architectural Designer – Design, planning drawings
• Structural Engineer – Structural assessments and beam calculations
• Planning Consultant – For contentious or conservation area projects
• Builder / Loft Specialist – Main contractor for construction
• Party Wall Surveyor – If the conversion affects shared walls
Timeline for a Loft Conversion
• Design & Approvals: 4–8 weeks
• Construction Phase: 6–12 weeks (depending on type and complexity)
• Inspections & Sign-off: Ongoing throughout build
Conclusion
Loft conversions offer a smart, practical way to expand your home and add value—especially in areas where space is limited. Whether you opt for a modest Velux conversion or a full-scale mansard extension, the right design, professional guidance from Draw and Plan, and regulatory compliance are key to a successful project. With thoughtful planning, your dusty attic could soon become the most desirable room in the house.