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 Reigate?
In Reigate, a mansard loft conversion typically costs £73,000–£106,500 for a typical rear mansard, including VAT at 20% (standard rate). Prices across the South East are typically 12% above the UK average for this kind of work, which is reflected in the range for Reigate. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £73,000–£106,500 |
| Higher specification | £106,500–£133,000 |
The main things that change the cost:
- Front, rear or both
- Roof covering: natural slate costs more
- Bathrooms and finishes
- Number of dormers and lead work
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 Reigate?
The approval route for Reigate is set by planning law 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
What we take care of:
- Planning drawings and application
- Party wall notices to both neighbours
- Staircase and fire-safe escape route
- Building control sign-off
- Structural design and calculations
- New roof structure, slate or tile covering and lead work
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 Reigate
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
We work across Reigate and neighbouring areas such as Redhill, Horley and Banstead. Postcodes we cover in Reigate include RH2.
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 sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about mansard loft conversions in Reigate
How much does a mansard loft conversion cost in Reigate?
In Reigate, a mansard loft conversion typically costs £73,000–£106,500 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 Reigate?
Yes. We build mansard loft conversions across Reigate, including postcodes RH2. Every project starts with a free home visit.
Can I stay at home?
Usually. The new roof is built under a temporary cover so the house stays dry.
Does a mansard need planning permission?
Almost always, because it changes the roof shape. Councils assess it against local design guidance.
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.
