House Extensions in Southampton
Extending is almost always cheaper than moving once you have added up stamp duty, agents' fees and the cost of the move itself. We design and build single and double-storey extensions across Southampton and Hampshire, and we manage the whole thing — drawings, planning, building control and the build.
Extensions built end to end, not handed between trades
An extension touches every trade in the building: groundworks, brickwork, steel, roofing, glazing, electrics, plumbing, plastering and decorating. The projects that go wrong are usually the ones where nobody owns the join between one trade and the next.
We run extensions as a single contract with one project manager. That person books the trades, sequences the work, arranges the building control inspections and tells you what is happening this week and next. If a delivery slips or the weather turns, you hear it from us before you notice it yourself.
A free site visit costs you nothing and usually answers most of the questions on this page.
Types of extension we build in Southampton
The right answer depends on your plot, your budget and what you actually need the space for. We will tell you honestly if a loft conversion or an internal reconfiguration would give you more for your money than building outwards.
- Single-storey rear extensions — the most common project we build, typically opening a kitchen into a family dining space
- Side return and wrap-around extensions — reclaiming the dead alley alongside Victorian and Edwardian terraces
- Double-storey extensions — adding a room downstairs and a bedroom or bathroom above
- Orangeries and glazed extensions — lantern rooflights, bi-fold and sliding doors
- Porches and utility extensions — small footprint, quick to build, immediately useful
- Annexes and garden rooms — separate accommodation for family or work
From first sketch to final inspection
We start with a free site visit. We look at the ground, the drains, the existing structure and what you are trying to achieve, then set out the realistic options with rough costs attached. If the project is worth pursuing, we produce a written, itemised quotation.
From there we arrange measured drawings, structural calculations where steels are involved, and either a permitted development check or a full planning application with Southampton City Council or your borough council. Building regulations approval is arranged and the inspections are booked as the build progresses, so you finish with a compliant building and the paperwork to prove it.
House Extensions in Southampton
Photographs from our own sites across Southampton and Hampshire.
Thinking about house extensions?
Book a free site visit and we will set out the realistic options with costs attached.
House Extensions — FAQs
The questions Southampton homeowners ask us most often about this work.
How much does a house extension cost in Southampton?
Cost is driven by footprint, ground conditions, the amount of glazing, the level of finish and whether services have to move. A modest single-storey rear extension with a standard specification sits at one end of the range and a double-storey extension with structural steel and bi-fold doors at the other. We give you an itemised written quotation after a free site visit, so you can see the cost of each element and adjust the specification rather than the budget.
Do I need planning permission for a house extension?
Many single-storey rear extensions fall within permitted development rights, subject to limits on depth, height, materials and how close you build to a boundary. Those rights are restricted in conservation areas and can have been removed by a previous condition. Double-storey extensions more often need a full application. We check the position with the council before we price the work and handle the application if one is needed.
Will I need building regulations approval as well?
Yes, almost certainly. Planning permission is about what the building looks like and how it affects neighbours; building regulations cover structure, insulation, fire safety, ventilation, drainage and electrical work. Extensions need building control sign-off regardless of whether planning permission was required. We arrange the application and book every inspection.
Can we stay in the house while you build?
In most cases yes. We seal the working area off from the rest of the house, protect floors and routes in and out, and only break through into the existing building at the latest sensible point. Where a kitchen is being lost for a period, we will tell you in advance so you can plan around it.
Do I need a party wall agreement?
If you are excavating close to a neighbouring property or building on or against a shared boundary, the Party Wall etc. Act 1996 is likely to apply and you will need to serve notice. We flag this early, because it takes time and is one of the more common causes of delay when it is left too late.
How long does a house extension take to build?
A straightforward single-storey rear extension usually runs to a couple of months on site once groundworks start, with design and approvals happening before that. Double-storey work takes longer. We give you a written programme with the quotation and update you if anything moves.
House Extensions across Southampton and Hampshire
We cover the whole city and travel throughout Hampshire. See the full list of areas we cover.
- Bitterne Park
- Bitterne
- Woolston
- Sholing
- Thornhill
- Peartree Green
- Portswood
- Highfield
- Swaythling
- Bassett
- Shirley
- Freemantle
- Millbrook
- Redbridge
- Southampton City Centre
- Ocean Village
- Bursledon
- Hamble-le-Rice
- Netley Abbey
- Hedge End
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