✓ Verified Google reviews·✓ Reviewed regularly·✓ Updated 31 July 2026
Written by Mark Reid,
Trades Editor ·Verified 31 July 2026
Southampton's housing stock is genuinely varied, which means builders here need to work across a wider range of construction types than you'd find in many other parts of the south. Victorian terraces in Shirley and Polygon sit alongside post-war council-built semis in Thornhill, Edwardian villas in Bassett, and modern new-build estates pushing out towards Hedge End and Totton. The city's proximity to the coast and the Solent also means ground conditions can be tricky in lower-lying areas, with clay and made-ground soils affecting anything from extension foundations to underpinning work. Builders who know Southampton know these quirks. They'll have dealt with period brickwork that doesn't match anything in a merchant's current catalogue, with Conservation Area restrictions in parts of the city centre, and with the planning sensitivities that come with working near listed buildings.
Every builder on this page was drawn from public third-party business listings and ranked by public review rating alongside review count, with a small additional lift for businesses showing a working website and phone number. We then checked each business's homepage to confirm that building work is genuinely what they primarily do, which is how unrelated trades get filtered out. Any listing flagged as permanently closed is removed automatically. Where you see a Trust Verified badge next to a business, that means they've passed our full independent verification, covering trade qualifications and accreditations, public liability insurance, trading history, customer review history, and registered company information. Our How We Verify page sets out the full list of what that involves. Businesses without that badge have not been independently verified by us, and it's on you to carry out those checks before you book anyone.
Before you commit to any builder, get at least two or three written quotes that break down labour and materials separately. Ask specifically about the groundworks and foundation approach if you're planning an extension, particularly on clay-heavy ground which is common across much of Southampton. Check that whoever you hire carries public liability insurance of at least £1 million and ask to see the certificate rather than just taking their word for it. For any structural work, a structural engineer's drawings will usually be required for Building Regulations approval, and your builder should be familiar with this process. Always agree a payment schedule tied to project milestones rather than paying large sums upfront, and get everything confirmed in writing before a single spade goes in the ground.
How We Select & Rate The Best Builders in Southampton
Rankings on this page are driven by public review rating and review count pulled from third-party business listings, with a small lift applied to businesses that have both a working website and a contactable phone number. We check each business's homepage to confirm that builders work is their primary trade, which keeps unrelated businesses off the page. Permanently closed listings are removed automatically. Businesses displaying a Trust Verified badge have additionally passed our full verification process covering qualifications, accreditations, public liability insurance, trading history, customer review history, and registered company information. See our How We Verify page for the complete details. All other businesses listed here have not been independently verified by us, and inclusion is not an endorsement. Always do your own checks before hiring.
Recommended and Featured listings are paid placements, so a business's fee affects whether and where it appears. Every other listing is ranked on rating and review count from third-party business listings. How we rank & verify →
G.M.P Contractors Limited provides comprehensive building services to clients across Southampton and the SO17 area. The company has earned a perfect 5-star rating from 19 verified Google reviews, reflecting their commitment to quality workmanship and customer satisfaction. Based on Broadlands Road, they handle a range of construction and building projects for residential and commercial properties.
Covering extensions, renovations, and new builds, AOM Building Contractors Ltd operates out of Southampton's SO18 area and holds a perfect five-star rating across 13 Google reviews. The company works on both residential and commercial projects, offering a range of general building services to clients across the city and surrounding areas.
Maidanbuild Homes is a construction company providing building services throughout Southampton and the surrounding areas. Based on Ocean Way, the firm has earned a 5-star rating from 10 verified customer reviews, reflecting their commitment to quality workmanship. They serve clients across the SO14 postcode area and beyond, handling various residential and commercial building projects.
A building contractor serving Southampton and the surrounding area, White Build covers residential construction and general building work. The company holds a perfect five-star rating across its Google reviews, suggesting consistent workmanship and straightforward client communication. It operates as a local outfit rather than a large firm, which suits homeowners looking for direct contact with the people carrying out the work.
Greaves Brickwork & Construction Ltd provides building and brickwork services throughout Southampton from their SO16 base. The company has earned a 5-star rating from 6 verified customer reviews on Google. Their services cover general construction work and specialist brickwork projects for residential and commercial clients in the Southampton area.
Spitfire Ceilings Ltd provides professional building services from their base on Burgess Road in Southampton. The company serves the SO16 area and surrounding neighbourhoods with reliable construction work. With a perfect 5-star rating from 6 verified customer reviews, they have established a strong reputation for quality workmanship in the local community.
Waterside Installations Ltd operates as a building contractor from their base at Carlton Commerce Centre in Southampton SO14. The company maintains a perfect 5-star Google rating based on 3 verified customer reviews, reflecting their commitment to quality workmanship. They serve the Southampton area with professional building services for both residential and commercial clients.
Transparency notice: Recommended and Featured listings are paid placements, so a business's fee affects whether and where it appears. All other listings are ranked by a combined score drawn from ratings and review counts published on third-party business listings, plus basic completeness signals such as a working website and phone. A Trust Verified badge means we have independently checked that business's documents; businesses without it have not been independently verified by us. How we verify →
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Day rates for a sole-trader builder in Southampton typically run from around £200 to £300 per day, though specialist trades or more experienced contractors can charge more. For project-based work, a single-storey rear extension will generally cost somewhere between £25,000 and £50,000 depending on size, specification, and finish. A loft conversion in a typical Edwardian or Victorian semi tends to come in between £35,000 and £60,000. Full house renovations vary enormously but budgeting £800 to £1,500 per square metre for a mid-range finish is a reasonable starting point. Groundworks add cost on clay-heavy sites, which is worth factoring in early. Always get two or three detailed, itemised quotes before committing, and make sure each one covers the same scope so you're comparing like with like.
Do I need planning permission for a home extension in Southampton?
Not always. Many single-storey rear extensions fall under Permitted Development rights, meaning you don't need a full planning application as long as the extension stays within certain size limits and your property isn't in a designated area. However, Southampton City Council has Article 4 Directions in some conservation areas, including parts of the city centre and older residential neighbourhoods, which remove some Permitted Development rights. If you're on a new-build estate, the original planning consent may also have removed those rights. It's worth checking with Southampton City Council's planning portal or using a pre-application enquiry service before your builder starts. Even when planning permission isn't required, Building Regulations approval almost always is for structural work, new electrics, or anything affecting insulation or drainage.
How long does a typical home extension take to build in Southampton?
A straightforward single-storey rear extension usually takes eight to fourteen weeks once work starts on site, though that figure assumes the weather cooperates and there are no surprises in the ground. Groundworks on clay soil, which is common across much of Southampton, can take longer than on more stable ground, particularly if the foundations need to go deeper. A two-storey extension or a loft conversion typically adds several weeks to that. Factor in lead times too. Good builders in Southampton are often booked up two to four months in advance, and getting materials ordered early avoids delays mid-project. The planning and Building Regulations application process, if required, can add two to three months before work even begins.
What should I check before hiring a builder in Southampton?
Start with their public liability insurance. Ask to see the actual certificate and check the level of cover, which should be at least £1 million for most domestic projects and higher for larger builds. Ask whether they'll be handling the Building Regulations application themselves or whether you need to appoint an approved inspector. Check references from recent local jobs, ideally properties in the same postcode area so you know they're familiar with local planning conditions and soil types. If the quote seems unusually low, ask what's been excluded. Drainage work, structural engineer fees, and skip hire are commonly left out of initial estimates. A signed contract covering scope, timeline, payment schedule, and what happens if there are variations is essential before any work starts.
Can a builder in Southampton handle a garage or outbuilding conversion?
Yes, most general builders in Southampton will take on garage conversions, which are one of the more cost-effective ways to add usable space without extending the footprint of your home. A straightforward integral garage conversion typically costs between £8,000 and £18,000 depending on the level of finish and what the space will be used for. You'll almost certainly need Building Regulations approval even if planning permission isn't required, covering things like insulation, ventilation, damp-proofing, and the new floor construction. If the garage is detached and you're adding habitable accommodation, the structural requirements become more involved. Some Southampton properties also have restrictive covenants on their title deeds preventing garage conversions, so it's worth checking with your solicitor before you start.
How do I compare and choose between builders in Southampton?
Get a minimum of three written quotes and make sure each one breaks down labour, materials, and any subcontractor costs separately. Ask each builder directly which parts of the work they'll do themselves and which they'll subcontract out. Check that they carry current public liability insurance and ask to see the certificate. Look at their recent work by asking for references from jobs completed in the past twelve to eighteen months, ideally in Southampton itself so you can verify they understand local planning requirements and common construction challenges in the area. Search their company name on Companies House to confirm they're a registered business and check when the company was incorporated. If you're spending significant money, consider using a formal contract such as the JCT Minor Works form. Two or three similar quotes that are close together in price give you a much better picture of real market cost than one outlier in either direction.
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