What is a mansard loft conversion?
A mansard loft conversion rebuilds the roof with a nearly vertical slope (about 72 degrees) and a flat top, effectively adding a new storey. Small dormer windows sit within the steep slope. Mansards are common on period terraces in towns and cities.
How much does a mansard loft conversion cost in Bedfordshire?
In Bedfordshire, a mansard loft conversion typically costs £69,000–£100,500 for a typical rear mansard, including VAT at 20% (standard rate). That range is adjusted for the East of England, where domestic building work typically costs around 6% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £69,000–£100,500 |
| Higher specification | £100,500–£125,500 |
Your quote will depend mainly on:
- Scaffolding on busy streets
- Party wall surveyor fees
- Front, rear or both
- Roof covering: natural slate costs more
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a mansard loft conversion in Bedfordshire?
Before anything is built in Bedfordshire, we confirm which approvals apply in England. In England a mansard almost always needs planning permission because it changes the roof shape. Many councils publish design guidance for mansards on terraced streets, and some streets are more likely to be approved where neighbours already have one.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a mansard loft conversion:
- New roof structure, slate or tile covering and lead work
- Party wall notices to both neighbours
- Building control sign-off
- Staircase and fire-safe escape route
- Insulation, electrics, plumbing and plastering
- Structural design and calculations
How long does it take?
The build itself usually takes 9 to 12 weeks on site, after planning approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Bedfordshire
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
Towns we cover in Bedfordshire include Luton, Bedford, Dunstable, Leighton Buzzard, Ampthill and Kempston Hardwick.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about mansard loft conversions in Bedfordshire
Do you build mansard loft conversions in Bedfordshire?
Yes. We build mansard loft conversions across Bedfordshire, including postcodes LU1, LU2, LU3, LU4 and LU5. Every project starts with a free home visit.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
Why choose a mansard over a dormer?
A mansard gives more usable floor space and a neater appearance from the street, but costs more and needs planning permission.
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.
How much does a mansard loft conversion cost in Bedfordshire?
In Bedfordshire, a mansard loft conversion typically costs £69,000–£100,500 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.