Mansard loft conversions
Services
Get the maximum space possible by reshaping your roof into a new living level — ideal for period properties and city homes.
What Is a Mansard Loft Conversion?
A Mansard loft conversion alters your roof structure to create a nearly vertical rear slope and a flat roof, effectively turning your attic into a new full-height floor.
Named after French architect François Mansart, this conversion style is especially popular in urban areas where space is limited but homeowners want a full upper storey.
Because a Mansard conversion adds an entire additional floor, it often boosts property value by 20–25% and dramatically enhances daily living comfort.
- Creates a full additional storey, adding significant square footage.
- Ideal for townhouses, terraces and period properties.
- Offers the best headroom and internal layout flexibility.
- Blends beautifully with existing architecture for a natural extension of your home.
- High ROI — one of the best loft conversion types for increasing property value.
Conversions, built to last
Why homeowners choose us?
Full design & planning service
We produce measured surveys, 3D concept plans and handle planning or permitted development paperwork where required.
Turnkey build
Structural work, roofing, insulation, electrics, plumbing and finishes — managed by our experienced project managers.
Transparent pricing & guarantees
Clear fixed quotes, milestone payments and a warranty on structural works.
Local, reliable craftsmen
Our craftsmen take pride in every detail — delivering high-quality workmanship, honest communication, and results you can trust.
Free survey & brief
We visit, measure and confirm feasibility.
Design & estimate
Concept drawings, layout options and a fixed price.
Approvals & structural design
Building regs drawings and any required planning.
Build & project management
Site set-up, structural works, roofing, windows, insulation and finishes.
Handover & guarantee
Snagging, client walkthrough and warranty documentation.
Recent projects
Gallery
Take a look at some of our recent projects to see the quality of our work and the transformations we’ve achieved for our clients.
FAQ's
Questions our clients ask
Have questions about how our process works, what to expect, or how to get started? We’ve answered some of the most common queries below to help you plan your project with confidence.
Contact UsDo I need planning permission for a Mansard loft conversion?
Yes. Mansard conversions almost always require planning permission as they change the roof shape and height. We handle the application process on your behalf.
How long does a Mansard conversion take?
Typically 10–14 weeks from construction start to completion, depending on design complexity.
Can I combine a Mansard with a rear dormer or L-shape?
Yes — hybrid designs are possible to maximise space and light, especially in larger properties.
How disruptive is the process?
Construction mainly happens externally during the first stages. We maintain site cleanliness and minimise interior disruption until stair installation.
How much space does a Mansard add?
Depending on property size, a Mansard can add up to 50m² of new living area — the largest gain among all loft types.
What our clients say
Customer reviews
Don't just take our word for it - hear from our satisfied customers
reviewed on
26 reviews
This was the second time we worked with ICS, having completed a loft conversion with them in 2023. This time they built our kitchen extension and once again the quality of their work was extremely high. Would not hesitate to recommend ICS or to work with them again.
Ella Kahn
London
We have been really very happy with ICS. The company provided a reasonable quote, detailed information on the process and was very responsive to queries. They provided an online portal which helped us to track stages of the build itself as well as finance.
Michael Thompson
London
ICS were such a good choice. Absolutely professional and meticulously honest from start to finish. Site manager Stas was always available to smoothly handle any issues that arose. Builders all friendly and competent. Happy with our experience and our new loft.
Adam Rasmussen
London
I had the pleasure of working with ICS for a series of projects on my property (SE6), including a sideways rear extension, bathroom refit, the addition of a laundry room, complete replumbing, and the removal of an old chimney. The entire crew was not only skilled but also friendly and punctual.
George Randerson
London
We recently had ICSolutions complete a loft conversion, adding two spacious bedrooms and a shower room. From start to finish, the experience was excellent. The team was professional, respectful, and a pleasure to work with. They were always prompt with their timing and kept us well-informed.
Fatima Ali
London
We just finished a loft conversion with ICS, and I can’t say enough good things about them. They were absolutely amazing from start to finish! Stas, the project manager, was fantastic – completely on top of everything and led the project with such competence and attention to detail.
Natasha
London
Ready to work together?
Let’s bring your vision to life
Whether you’re planning a loft conversion, extension, or full renovation, our expert team is here to make it happen — on time, on budget, and with exceptional quality.
