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 Ashton-under-Lyne?
In Ashton-under-Lyne, a mansard loft conversion typically costs £61,000–£89,500 for a typical rear mansard, including VAT at 20% (standard rate). The guide for Ashton-under-Lyne 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 |
Your quote will depend mainly on:
- Scaffolding on busy streets
- Party wall surveyor fees
- Front, rear or both
- Number of dormers and lead work
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 Ashton-under-Lyne?
Whether you need planning permission depends on your house and its location 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
- Staircase and fire-safe escape route
- Planning drawings and application
- Party wall notices to both neighbours
- Building control sign-off
- Insulation, electrics, plumbing and plastering
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 Ashton-under-Lyne
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
Projects in Ashton-under-Lyne (OL7) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 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 Ashton-under-Lyne
How much does a mansard loft conversion cost in Ashton-under-Lyne?
In Ashton-under-Lyne, 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.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
Can I stay at home?
Usually. The new roof is built under a temporary cover so the house stays dry.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
How long does a mansard loft conversion take in Ashton-under-Lyne?
Typically 9 to 12 weeks on site, after planning approval. Design and approvals beforehand usually take 3 to 4 months.