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 Tooting?
In Tooting, a mansard loft conversion typically costs £84,500–£123,500 for a typical rear mansard, including VAT at 20% (standard rate). The guide for Tooting reflects typical costs in London, roughly 30% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £84,500–£123,500 |
| Higher specification | £123,500–£154,500 |
Your quote will depend mainly on:
- Number of dormers and lead work
- Party wall surveyor fees
- Bathrooms and finishes
- Roof covering: natural slate costs more
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 Tooting?
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.
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most mansard loft conversions:
- Party wall notices to both neighbours
- Planning drawings and application
- Building control sign-off
- New roof structure, slate or tile covering and lead work
- Structural design and calculations
- Dormer windows
How long does it take?
Allow 9 to 12 weeks on site, after planning approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Tooting
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
Tooting sits in Greater London, about 6 miles south of central London. We cover the whole of Tooting, including postcodes SW17 and SW19.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about mansard loft conversions in Tooting
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
How much does a mansard loft conversion cost in Tooting?
In Tooting, a mansard loft conversion typically costs £84,500–£123,500 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 Tooting?
Yes. We build mansard loft conversions across Tooting, including postcodes SW17 and SW19. Every project starts with a free home visit.