Mansard loft conversions in St Albans

Covering St Albans

Alongside St Albans, we also cover Harpenden (5 miles to the north), Hatfield and Hemel Hempstead.

Homes in the East of England

Across the East of England, newer estates often have integral garages and room for rear extensions, while older towns have Victorian terraces and conservation areas that shape what can be built.

What does a mansard loft conversion involve?

Mansards are a bigger structural job than other conversions because the roof is largely rebuilt. They normally need planning permission, and many councils have design guides setting the angle, materials and window style. We prepare the design to those guides and build in slate, lead and timber or approved alternatives.

Planning application to local design guidance
Structural design and party wall process
Slate cladding and lead-clad dormers

What will a mansard loft conversion cost?

Indicative costs for mansard loft conversions. London and the South East usually sit towards the top of each range.

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

Planning and building rules in St Albans

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 can change the price or programme?

A mansard nearly always involves party walls on both sides of a terrace.
The roof is open for longer than with a dormer, so weather protection matters.

What happens after I enquire?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

Mansard loft conversions: common questions

How long does a mansard take?

Around 10 to 14 weeks on site after planning approval.

Why choose a mansard over a dormer?

A mansard gives more usable space and often fits a street better where neighbours already have one.

Who deals with the council for a project in St Albans?

We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.

Also covering

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