Services
Extensions
House Extensions That Genuinely Add Value
A well-designed, well-built extension does three things: it gives you the space the existing house does not have, it improves the flow and feel of the whole property, and it adds real resale value. A badly built extension does none of these — and costs a lot of money to correct.
Construction IMC delivers extension projects across the UK for homeowners, architects and developers. Our extensions are treated the same way as any other build: engineered properly, priced transparently, programmed realistically, and delivered by directly employed trades under site supervision.
Types of Extension We Build
Single-Storey Rear Extensions
The most common form of extension — extending outwards at the back of the property, usually to create a larger kitchen, dining or living space. Delivered with the integration with the existing house that makes the finished room feel original rather than tacked on.
Double-Storey Extensions
Extending over two storeys — adding to the ground floor living space and the first floor bedroom or bathroom accommodation. More complex than single-storey, and more valuable per square foot.
Side Return Extensions
The London speciality — filling in the awkward side alley on Victorian terraces to create open-plan kitchen-diners. We have delivered side return extensions extensively across London and similar urban housing stock.
Wrap-Around Extensions
Combining a side return and a rear extension to create a fully reconfigured ground floor with substantial additional footprint. The most transformative of the common extension types.
Loft Conversions
Converting unused loft space into bedrooms, bathrooms or home office space, including dormer extensions, hip-to-gable conversions and mansard extensions where planning allows.
Garden Room and Outbuilding Extensions
Substantial garden buildings — studios, annexes, pool houses — built to habitable standards with services, insulation and permanent foundations.
Planning Permission and Permitted Development
Many single-storey extensions can be delivered under Permitted Development Rights, subject to size, height and neighbour distance restrictions. Larger extensions, double-storey extensions, extensions in Conservation Areas, and extensions to Listed Buildings all require planning permission. We can advise on the likely route and, where needed, work alongside planning consultants and architects to prepare the application.
Our Extension Process
1. Site visit
We come to the property to understand the scheme, the constraints and the logistics.
2. Design coordination
Working with your existing architect or introducing ours.
3. Planning and Building Control
We handle the build regs process; your architect handles the planning drawings.
4. Fixed-price quotation
Transparent pricing on a defined scope.
5. Party Wall Agreements
We coordinate with your Party Wall surveyor where neighbouring properties are affected.
5. Party Wall Agreements
We coordinate with your Party Wall surveyor where neighbouring properties are affected.
7. Handover
Snagged, certificated and fully documented.
Programme Expectations
Typical extension programmes run from 12 to 14 weeks for a simple single-storey rear extension, up to 20 to 26 weeks for a substantial double-storey or wrap-around extension, and 6 to 9 months for larger basement projects. We commit to realistic programmes and stick to them — if we think your architect's programme is optimistic, we will tell you at tender stage rather than discover it in month three.
Why Construction IMC for Your Extension
- A proper contractor, not a general builder — engineered delivery, real site management, full compliance.
- Fixed pricing with no surprises in month four.
- Directly employed trades — your programme is not vulnerable to a single sub-contractor having a better offer somewhere else.
- Full insurance and building control — every element of the works is certificated.
- Clean site discipline — dust protection, noise management, considerate works in residential streets.
Get Your Extension Quoted
Share your plans — or just tell us what you are thinking — and we will arrange a site visit. Call +44 7392 989543 or enquire via the contact page.