Mansard loft conversions in St Helens

Covering St Helens

Alongside St Helens, we also cover Prescot, Ashton-in-Makerfield (4 miles to the north-east) and Huyton.

Homes in the North West

Terraced housing is a defining feature of many North West towns, which brings party walls and narrow access into most projects, with more space to extend on suburban semis.

What do you get with a mansard loft conversion?

A mansard loft conversion replaces one or both slopes of a roof with a near-vertical wall, typically at 70 degrees, with small dormer windows set into it. It creates almost a full extra storey and is common on terraced houses in towns and cities, particularly in London.

Structural design and party wall process
Slate cladding and lead-clad dormers
En-suite, electrics and fire safety

How much should I budget for a mansard loft conversion?

Typical ranges for mansard loft conversions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.

Mansard loft conversions	Guide price incl. VAT
Rear mansard	£65,000 to £85,000
Front and rear (double) mansard	£80,000 to £110,000

How is a mansard loft conversion approved in St Helens?

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.

Mansard conversions change the shape of the roof significantly, so they usually need planning permission in England. Many councils publish guidance on mansard design.

What should I think about before starting?

A mansard nearly always involves party walls on both sides of a terrace.
Council design guides often require natural slate and lead.

From first call to completion

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

Mansard loft conversions: common questions

Does a mansard need planning permission?

Almost always, because it changes the roof profile.

How long does a mansard take?

Around 10 to 14 weeks on site after planning approval.

Do you work in St Helens?

Yes. St Helens is within our coverage for mansard loft conversions, along with nearby Prescot and Ashton-in-Makerfield.

Mansard loft conversions near St Helens

Learn more about mansard loft conversions, or see every project we cover in St Helens.