Mansard Roof Loft Conversions London

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Create a dramatic increase in living space with a beautifully designed Mansard loft conversion from LXR Construction. We specialise in mansard roof conversions across London, helping homeowners transform their roof space into full-height, multi-room living areas. Whether you’re looking to add multiple bedrooms, a luxury master suite, office space, or a complete upper-floor redesign, we manage every stage — from architectural planning and roof restructuring to the final interior finish.

Why Choose a Mansard Loft Conversion?

  • Maximum Head Height & Space – Mansard loft conversions transform the entire roof into nearly vertical walls, offering the most internal space of all loft conversion types — ideal for full bedrooms, bathrooms, and upper-floor living.
  • Perfect for London Terraces & Period Homes – Mansards are especially suited to Victorian and Georgian houses, blending seamlessly with traditional London architecture and adding a new floor that feels like an original part of the property.
  • Ideal for Multiple Rooms – Because of the increased headroom and steep rear roof angle, mansards allow for more practical layouts — including two or more bedrooms, bathrooms, walk-in wardrobes, or dedicated office areas.
  • Great for Future Value – A mansard loft conversion can add the equivalent value of a full floor extension, offering one of the highest return-on-investment options for London homeowners.
  • Visually Attractive & Planning-Friendly – Mansard designs often gain planning approval more easily in heritage areas compared to box dormers, thanks to their softer profile and heritage-appropriate structure.
mansard loft conversion on property

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Our Step-By-Step Process to Building Your Mansard Roof Loft Conversion

1

Consultation & Design

We begin by understanding how you plan to use your new loft space and what style suits your property. Our team explores roof angle, dormer structure, head height, staircase placement, glazing options and overall layout. We then produce a bespoke design that maximises space, comfort and natural light.

2

Planning & Approvals

Mansard roof conversions almost always require planning permission due to changes in roof structure and height. We handle everything — architectural drawings, planning submission, structural calculations, party wall agreements and building regulations compliance — ensuring a smooth approval process.

3

Construction & Project Management

Our specialist mansard conversion team manages all stages of the build. A dedicated project manager oversees structural roof alterations, steelwork, brick/roof construction, insulation, plumbing, electrics, glazing and internal works. You receive frequent updates throughout the build for complete confidence.

4

Completion & Interior Fit-Out

Once the structural work is complete, we finish your new space with flooring, plastering, lighting, heating, bathrooms, custom joinery and full decoration. We then walk you through the completed conversion and ensure every detail meets our high standards.

How Much Does A Mansard Roof Loft Conversion In London Cost?

Costs vary depending on roof structure, size, internal layout and level of finish. As a guide:

  • £65,000 – £110,000+ for a standard mansard loft conversion
  • £110,000 – £180,000+ for multiple rooms with bathroom installations
  • £180,000 – £250,000+ for large, premium multi-room upper floors

A full itemised quote is provided after a survey and design consultation.

Will a Mansard Roof Loft Loft Conversion Add Value to a property?

Yes — significantly. A mansard conversion can increase property value by 10–30%, especially when adding multiple bedrooms and bathrooms. It offers one of the highest long-term returns for London homeowners looking to add space intelligently.

Frequently Asked Questions

A mansard loft conversion reshapes the roof into a near-vertical rear slope, creating a full-height upper floor with maximised internal space.

Almost always, yes. Mansard conversions involve major roof alterations, so planning approval is required — which we handle for you.

Mansards offer more internal space, higher ceilings and better long-term value, while dormers are cheaper and less structural. We advise the best option for your home.

Most projects take 10–18 weeks, depending on structure, plumbing and interior finishes.

Yes — mansards often allow for multiple rooms due to increased footprint and usable ceiling height.

They are most common on terraced and period homes but can be adapted for many property types following structural assessment.

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    Our Mansard Loft Conversion Services

    Rear Mansard Conversions

    The most popular solution for London terraces — expanding roof space to full-height rooms.

    Double Mansard Loft Conversions

    Create a full upper floor across front and rear roof slopes for maximum room space.

    Mansard with Ensuite / Bathroom Installations

    Add luxury living with modern bathrooms, underfloor heating, Velux rooflights and bespoke fittings.

    Mansard Conversions for Multi-Bedroom Layouts

    Ideal for adding two bedrooms, an office, or a private master suite.