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Get instant planning compliance assessment for your loft conversion project. Professional reports covering dormer windows, roof lights, and volume calculations.
Loft Conversion Summary
Popular Loft Conversion Types
Professional assessment for all types of loft conversions
Roof Light Conversions
Simple loft conversions using existing roof space with roof lights for natural light.
- No external roof changes
- Roof lights within permitted limits
- Internal staircase required
- Volume limits still apply
Rear Dormer Conversions
Loft conversions with rear-facing dormers to increase headroom and natural light.
- Rear dormers under permitted development
- Volume calculations critical
- Height restrictions apply
- Material matching required
Complex Loft Conversions
Advanced conversions requiring planning permission due to size or positioning.
- Side-facing dormers
- Volume over permitted limits
- Full planning permission required
- 8+ week approval process
Loft Conversion Planning Requirements
Volume Limits
Loft conversions are limited to 40 cubic metres for terraced houses and 50 cubic metres for detached properties.
Height Restrictions
No part of the roof extension can be higher than the highest part of the existing roof structure.
Dormer Restrictions
Dormers can only face the rear of the property. Side-facing dormers require full planning permission.
Quick Volume Calculator
Volume Allowances
50 cubic metres
40 cubic metres
What Counts Towards Volume
- Dormer windows and extensions
- Roof lights projecting >150mm
- Any additional roof height
- Previous roof extensions since 1948
Important Loft Conversion Considerations
Key factors to consider before starting your loft conversion project
Volume Calculations
Loft conversions are limited to 40 cubic metres for terraced houses and 50 cubic metres for detached properties.
Dormer Restrictions
Dormers can only face the rear of the property. Side-facing dormers always require full planning permission.
Height Restrictions
No part of the roof extension can be higher than the highest part of the existing roof structure.
Roof Window Limits
Roof lights that project more than 150mm from the roof slope count towards your permitted development volume allowance.
Conservation Areas
Properties in conservation areas have additional restrictions and may need full planning permission for roof extensions.
Building Regulations
All loft conversions require Building Regulations approval for structural safety, fire safety, and insulation requirements.
Previous Extensions
All roof extensions since 1948 count towards your permitted development allowance. Previous work affects available volume.
Material Matching
External materials should be similar in appearance to the existing house, particularly for visible roof sections.
Article 4 Directions
Local authorities can remove permitted development rights in specific areas. Check for any Article 4 directions affecting your property.
Frequently Asked Questions
Common questions about loft conversion planning permission
What Our Customers Say
Real feedback from homeowners who used our loft conversion assessment service
"The loft conversion report was incredibly detailed and helped us understand exactly what we could build under permitted development. Saved us thousands in planning fees."
"Clear guidance on volume calculations and dormer restrictions. The professional report gave us confidence to proceed with our loft conversion project."
"Excellent service that identified potential issues early. The report helped our architect design a compliant loft conversion from the start."
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