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 Hadleigh?
In Hadleigh, a mansard loft conversion typically costs £69,000–£100,500 for a typical rear mansard, including VAT at 20% (standard rate). We start from a UK-wide guide and adjust it for the East of England, where labour and materials are typically about 6% above average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £69,000–£100,500 |
| Higher specification | £100,500–£125,500 |
The main things that change the cost:
- Front, rear or both
- Number of dormers and lead work
- Roof covering: natural slate costs more
- Bathrooms and finishes
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 Hadleigh?
Before anything is built in Hadleigh, 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.
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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
What we take care of:
- Dormer windows
- Building control sign-off
- Structural design and calculations
- Planning drawings and application
- Insulation, electrics, plumbing and plastering
- 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 Hadleigh
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
If your home is in Hadleigh or close by in South Benfleet, Rayleigh and Canvey Island, a free home visit is the first step.
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
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 Hadleigh
Do you build mansard loft conversions in Hadleigh?
Yes. We build mansard loft conversions across Hadleigh, including postcodes SS7. 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.
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.
How much does a mansard loft conversion cost in Hadleigh?
In Hadleigh, a mansard loft conversion typically costs £69,000–£100,500 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.