General Building

House Extensions Northampton

A house extension is one of the biggest projects most homeowners take on, and it's also one where the difference between a well-managed build and a poorly coordinated one shows up in delays, cost overruns and a finish that doesn't quite match the rest of the house. We build house extensions across Northampton and Milton Keynes, managing the project from groundworks through to a finished, decorated space.

Types of Extension

  • Single-storey rear extensions, the most common type, typically extending a kitchen or living space into the garden

  • Side return extensions, extending into the often-unused side passage on terraced and semi-detached homes

  • Double-storey extensions, adding space on both floors, generally more cost-effective per square metre than two separate single-storey projects

  • Wraparound extensions, combining a rear and side return extension into one continuous space

Note

Planning Permission for Extensions

Many single-storey rear extensions fall under Permitted Development, subject to specific limits on how far they can project from the original rear wall, which vary depending on whether the house is detached, semi-detached or terraced, and whether a larger home extension neighbour consultation scheme applies. Side and double-storey extensions are subject to their own specific rules and are more likely to need a full planning application. Given how much this depends on your specific house, its planning history, and any previous extensions already carried out, we'd always recommend confirming your exact position with West Northamptonshire Council or Milton Keynes City Council, or through an architect, before finalising a design, and we'll flag anything in your brief likely to affect this during our initial visit.

What an Extension Project Involves

  1. Design and planning, working with your architect or one we can recommend, to develop a design that meets your brief and any planning requirements

  2. Groundworks and foundations, sized appropriately for the extension and ground conditions

  3. Structural work, including brickwork, steel beams where needed, and the roof structure

  4. First fix trades, including plumbing and electrics run before the walls are closed up

  5. Plastering, and second fix trades including fitting doors, skirting and fixtures

  6. Decorating and final finishing, so the space is ready to use

Note

Building Regulations

All extension work needs to comply with current Building Regulations, covering structural safety, insulation, ventilation, fire safety and drainage among other areas. This applies regardless of whether the project needs full planning permission, and we'll handle Building Regulations applications and inspections as part of managing the project.

Why Choose Bridgework

  • One contractor managing the whole build, rather than you coordinating separate trades

  • Honest advice on planning requirements before you commit to a design

  • Experience managing Building Regulations applications and inspections

  • A clear, staged quote reflecting the full scope of the project

Areas We Cover

We cover Northampton and Milton Keynes, and within roughly 30 miles of both, including Wellingborough, Kettering, Rushden, Towcester, Daventry, Buckingham, Brackley, Bicester, Aylesbury, Leighton Buzzard, Dunstable, Luton, Bedford, Newport Pagnell, Olney, Stony Stratford, Bletchley, St Neots, Biggleswade and Corby.

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House Extension FAQs

This varies considerably by size and complexity, but as a general guide, a single-storey rear extension often takes several months from groundworks to finish, with larger or double-storey extensions taking longer.

Not necessarily, many single-storey rear extensions fall under Permitted Development within specific size limits, though side and double-storey extensions are more likely to need a full application. We'll assess your specific project during the initial consultation.

In most cases yes, particularly for rear extensions, though there will be periods of disruption, especially when the extension connects to the existing house. We'll talk through what to expect for your specific project.

We can work with an architect of your choice or recommend one we've worked with before, and we'll manage the build itself from groundworks through to finish.

Get a Quote for a House Extension

If you're considering a house extension in Northampton or Milton Keynes, get in touch to discuss your brief and get honest advice on what's achievable.

Monday to Friday, 8am to 6pm. Emergency and same-day callouts outside these hours.

07749 606444