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 Tyldesley?
In Tyldesley, a mansard loft conversion typically costs £61,000–£89,500 for a typical rear mansard, including VAT at 20% (standard rate). The guide for Tyldesley reflects typical costs in the North West, roughly 6% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £61,000–£89,500 |
| Higher specification | £89,500–£112,000 |
The biggest cost drivers are:
- Bathrooms and finishes
- Number of dormers and lead work
- Scaffolding on busy streets
- Front, rear or both
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a mansard loft conversion in Tyldesley?
Here is how the rules work for a mansard loft conversion 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical mansard loft conversion we handle:
- Dormer windows
- Structural design and calculations
- Planning drawings and application
- Building control sign-off
- Staircase and fire-safe escape route
- Insulation, electrics, plumbing and plastering
How long does it take?
The build itself usually takes 9 to 12 weeks on site, after planning approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Tyldesley
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
Tyldesley sits in Greater Manchester, about 10 miles west of Manchester. We cover the whole of Tyldesley, including postcodes M29.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about mansard loft conversions in Tyldesley
How much does a mansard loft conversion cost in Tyldesley?
In Tyldesley, a mansard loft conversion typically costs £61,000–£89,500 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
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.
Do you build mansard loft conversions in Tyldesley?
Yes. We build mansard loft conversions across Tyldesley, including postcodes M29. Every project starts with a free home visit.