Mansard loft conversions in Hertfordshire

Covering Hertfordshire

Our coverage across Hertfordshire includes Watford, Hemel Hempstead, Stevenage and St Albans.

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
Slate cladding and lead-clad dormers
En-suite, electrics and fire safety

How much should I budget for a mansard loft conversion?

Use these ranges to budget for mansard loft conversions; the survey turns them into a fixed price for the agreed specification.

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

Do you need permission for a mansard loft conversion in Hertfordshire?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it 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.
The roof is open for longer than with a dormer, so weather protection matters.

What happens after I enquire?

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
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 much does a mansard loft conversion cost?

Typically £65,000 to £110,000 including VAT, depending on whether one or both roof slopes are rebuilt.

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 Hertfordshire?

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

Mansard loft conversions near Hertfordshire

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