Mansard Loft Conversion
Maximise space with a full roof restructure and premium finish.
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Benefits of a Mansard Loft Conversion.
A mansard loft conversion is the most expansive option, reshaping one or both roof slopes into near-vertical walls. It delivers the maximum usable floor area and is often chosen for terraces and urban homes where space is at a premium.
What's Included
Every mansard loft conversion project includes architect-led design and full technical documentation.
- Measured survey and roof structure assessment
- Mansard roof design and planning drawings
- Structural engineering and steel coordination
- Party wall guidance for shared boundaries
- Building Regulations drawings for construction
Why work with us?
- Architect-led from day one
- Fixed fees, no surprises
- Planning success rate over 95%
- Direct communication throughout
What a Mansard Conversion Involves
Mansard conversions alter the roof profile to create a near-vertical rear wall:
- Maximum floor area across the full width of the loft
- Traditional detailing that blends well with period homes
- Flexible layouts for bedrooms, offices, and en-suites
Planning Considerations
Mansard loft conversions almost always require planning permission because the roof form changes significantly. Factors we consider include:
- Conservation Area requirements and local policies
- Street character and neighbouring rooflines
- Window placement and overlooking impacts
We handle the application and ensure the design aligns with local guidance.
Structure and Build Complexity
Mansards involve more structural work than dormers:
- Steel beams to support new roof loads
- Temporary roof protection during construction
- Longer build programme due to roof reconstruction
Common Questions
Do I need planning permission for a mansard loft conversion?
Yes. Mansard conversions significantly alter the roof shape and always require planning approval.
How long does a mansard conversion take?
Typically 12-16 weeks on site depending on complexity and internal fit-out.
Is a mansard suitable for terraced houses?
Yes. Mansards are common on terraced and period properties where maximising space is the priority.
Is a mansard conversion more expensive?
Yes. It is the most comprehensive loft conversion and carries a higher structural and build cost.