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 Tewkesbury?
In Tewkesbury, a mansard loft conversion typically costs £66,500–£97,000 for a typical rear mansard, including VAT at 20% (standard rate). Building costs in the South West are close to the UK average, so the figures for Tewkesbury are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £66,500–£97,000 |
| Higher specification | £97,000–£121,000 |
Your quote will depend mainly on:
- Roof covering: natural slate costs more
- Party wall surveyor fees
- Number of dormers and lead work
- Bathrooms and finishes
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a mansard loft conversion in Tewkesbury?
Before anything is built in Tewkesbury, 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
From survey to sign-off, the job normally involves:
- Planning drawings and application
- New roof structure, slate or tile covering and lead work
- Dormer windows
- Insulation, electrics, plumbing and plastering
- Party wall notices to both neighbours
- Staircase and fire-safe escape route
How long does it take?
Build time is typically 9 to 12 weeks on site, after planning approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Tewkesbury
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Projects in Tewkesbury (GL20) 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
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 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 Tewkesbury
Does a mansard need planning permission?
Almost always, because it changes the roof shape. Councils assess it against local design guidance.
How much does a mansard loft conversion cost in Tewkesbury?
In Tewkesbury, a mansard loft conversion typically costs £66,500–£97,000 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Do you build mansard loft conversions in Tewkesbury?
Yes. We build mansard loft conversions across Tewkesbury, including postcodes GL20. Every project starts with a free home visit.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.