Multi-storey extensions
Services
Transform your home with a seamless two-storey or double-storey extension. More rooms, more value — all under one roof.
What Is a Multi-Storey Extension?
A multi-storey extension (often a two-storey / double-storey extension) adds a new floor or floors to your existing home. Instead of building outward into the garden, you extend upwards or outwards with an extra storey above or beside existing rooms.
Because a multi-storey extension adds usable floorspace rather than just a room, it often yields a high increase in property value — particularly in urban areas or where footprint expansion is limited.
- Add multiple new rooms without expanding your home footprint.
- Ideal for growing families needing more bedrooms, bathrooms, or living area.
- Delivers significant increase in property value and usable space.
- Can be designed to blend with existing architecture or modernise your home.
- Full design, planning and build — handled by one trusted team.
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 multi-storey extension?
Usually yes — multi-storey additions often require full planning permission. We handle the planning process on your behalf.
How long does a multi-storey extension take?
Typical build time is between 3-6 months, depending on size, complexity and approvals.
Can it be disruptive to live in the house during construction?
Yes — there will be phases of noise, scaffolding and internal works. We manage this with protective measures, clear scheduling & project-management to minimise impact.
How much will it cost per m²?
Costs depend on design and materials. For example, on average multi-storey extension cost around £47,000 for a 30 m² two-storey extension. We’ll provide a detailed cost estimate after our initial survey.
Can I combine a multi-storey extension with loft conversion or basement works?
Yes — we offer hybrid designs combining upstairs extensions with loft conversions for maximum living space.Yes — we offer hybrid designs combining upstairs extensions with loft conversions for maximum living space.
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.
