Looking for the best house extension builders near me in Kent? This 2026 guide shortlists seven Maidstone and Kent-based extension specialists scored on years trading, range of services, customer reviews, accreditations and transparency. It is built for homeowners planning single-storey, two-storey, side return, wraparound or kitchen extensions across the county.

How we scored each builder

Every company on this list was assessed against the same six criteria. Scores are weighted equally so larger firms cannot drown out smaller, high-quality outfits:

• Years in operation and recorded trading history at Companies House or via Federation of Master Builders membership
• Range of extension services (single-storey, two-storey, side return, wraparound, loft conversion, garage conversion)
• Verified customer reviews on Google, Checkatrade, Trustpilot and FMB profiles
• Independent accreditations such as FMB, Kent Trading Standards and Checkatrade
• Transparency on pricing, deposits, warranties and timelines
• Geographic coverage across Maidstone, Medway, Tunbridge Wells, Sevenoaks, Ashford and the wider Kent region

Kent house extension builders at a glance

Below is a side-by-side summary of each shortlisted company. Pricing follows the typical 2026 Kent market range for a single-storey rear extension, which sits between £1,800 and £3,000 per square metre at standard specification, rising to £75,000 to £120,000 for premium spec (bifold doors, underfloor heating, structural glass). Each builder quotes individually after a site visit.

BDC Construction

• Location: Maidstone, Kent (covers Bearsted, Headcorn, Sevenoaks, Tunbridge Wells, Ashford, Canterbury, Medway)
• Year founded: 2011 (founder Ben has 20+ years’ building experience)
• Specialism: Single and two-storey extensions, side and rear additions, full renovations, loft conversions, new builds
• Best for: Homeowners wanting a referral-led builder with strong finishing standards and clear communication

RJ Construction Building Services Ltd

• Location: Allington, Maidstone, Kent
• Year founded: 2013 (rebranded 2019)
• Specialism: Extensions, structural alterations, renovations, conservatories, landscaping
• Best for: Larger residential and commercial builds where 100+ Google reviews and £2 million liability insurance matter

South East Building Service

• Location: Coxheath, Maidstone, Kent (covers Sevenoaks, Tonbridge, Tunbridge Wells, West Malling, Rainham)
• Year founded: 1994
• Specialism: Rear, side return, wraparound and over-structure extensions; loft conversions
• Best for: Buyers who prioritise long trading history and FMB plus Kent Trading Standards approvals

JK Construction (South East) Ltd

• Location: 98 Holland Road, Maidstone, Kent
• Year founded: Limited company incorporated 2016 with older trading history reported
• Specialism: New builds, extensions, conversions, loft conversions, commercial fit-outs
• Best for: Homeowners who want fixed-price quotes with no upfront deposit and a 10-year structural warranty

Total Extensions Kent

• Location: Ulcombe Road, Maidstone, Kent
• Year founded: Trading details not published; long-standing Maidstone presence
• Specialism: House extensions, kitchen extensions, orangeries, garden rooms, glass extensions, garage conversions
• Best for: Design-led extensions with in-house architectural drawings and planning support

M Richards Building and Roofing Services Ltd

• Location: Charing, Kent (serves Maidstone, Medway, Sevenoaks, Tunbridge Wells, Swale)
• Year founded: 1986 (roofing); building services arm added 10+ years ago
• Specialism: House extensions, loft conversions, garage conversions, roofing and project management
• Best for: Projects where roofing complexity sits alongside the extension build

Benchmarque Construction Ltd

• Location: Maidstone, Kent
• Year founded: Reports 30+ years trading; 50+ years combined team experience
• Specialism: Refurbishments, extensions, loft conversions, interiors and external landscaping
• Best for: Larger refurbishments and rebuilds where interior finishing is the priority

Jump to a builder

• 1. BDC Construction
• 2. RJ Construction Building Services Ltd
• 3. South East Building Service
• 4. JK Construction (South East) Ltd
• 5. Total Extensions Kent
• 6. M Richards Building and Roofing Services Ltd
• 7. Benchmarque Construction Ltd
• House extension FAQ

1. BDC Construction

Best for: Maidstone and Kent homeowners who want a referral-led extension builder with 20+ years of hands-on experience and a fixed point of contact throughout the build.

BDC Construction is a Maidstone-based family business founded in 2011 by Ben, with a portfolio built almost entirely on word-of-mouth referrals and repeat work across Kent.

Key details

• Founded in 2011; founder Ben has over 20 years of building experience
• Based in Maidstone, covering Bearsted, Boxley, Headcorn, Lenham, Hollingbourne, Staplehurst, Yalding, Tunbridge Wells, Tonbridge, Sevenoaks, Medway, Sittingbourne, Ashford and Canterbury
• Services: single and two-storey extensions, rear and side additions, porches, renovations, kitchen and bathroom refurbishments, loft conversions, barn and garage conversions, new builds, steelwork and temporary propping
• Fully insured, free quotes, can introduce architects if no drawings are in place
• Phone 01622 946189; email office@bdcconstructionltd.co.uk

Pros

• Direct relationship with the founder from quote to handover
• Testimonials reference tidy sites, partitioned occupied builds and on-budget delivery
• Plain-English guidance on planning permission versus building control
• Handles all trades so homeowners deal with one main contact

Cons

• Premium quality positioning rather than the cheapest quote on the market
• Smaller team than national contractors, so peak-season lead times can stretch
• Pricing is provided on enquiry rather than published online

Track record: Five-star testimonials on its own website include repeat customers using BDC for multiple extensions, garage conversions and loft conversions, confirming the referral-led growth model.

To enquire, request a free quote via the BDC Construction extensions service page, or browse completed extension projects across Kent.

2. RJ Construction Building Services Ltd

Best for: Homeowners and small commercial clients wanting a larger Maidstone-based team with a deep public review trail and high-spec insurance cover.

Established in 2013 by friends Robert and James and rebranded in 2019, RJ Construction operates from Allington, Maidstone, and covers extensions, structural alterations, conservatories, landscaping and commercial fit-outs.

Key details

• Founded in 2013; rebranded to RJ Construction Building Services Ltd in 2019
• Based at Unit 1, Abbeygate Court, Stockett Lane, Maidstone ME15 0PP
• Over 250 completed projects in 11 years across the South East
• £2 million public liability insurance; 10% deposit on projects over £2,000 with staged payment plan
• Quoted lead times of 8 to 12 weeks for single-storey extensions and 16 to 20 weeks for double-storey extensions
• Phone 01622 679744

Pros

• 100+ Google reviews provide a deeper public review trail than most local rivals
• Transparent payment schedule with no large upfront deposit
• Combined domestic and commercial expertise
• Free, no-obligation estimates

Cons

• Single Trustpilot listing carries some mixed reviews, so cross-check on Google
• Less focus on planning and architectural drawings than design-led specialists
• Larger pipeline can mean a wait for a start date

Track record: Per its own About page, RJ Construction has delivered 250+ projects over 11 years and accumulated more than 100 Google reviews, which puts it among the more publicly reviewed extension builders in Kent.

Get a free estimate via rj-construction.co.uk or call 01622 679744.

3. South East Building Service

Best for: Risk-averse homeowners who put a high weighting on long trading history and multiple independent accreditations before signing a contract.

South East Building Service is a Maidstone family-run firm that has traded for over 25 years, with FMB membership since 2020 and Kent Trading Standards plus Checkatrade approval.

Key details

• Established in 1994; over 25 years of continuous trading
• Based at Blossom Lodge, Stockett Lane, Coxheath, Maidstone ME15 0QG
• FMB member since 2020, Kent Trading Standards Checked, Checkatrade approved
• Specialises in rear, side return, wraparound, over-structure and double-storey garage extensions, plus loft conversions and attic rooms
• Covers Maidstone, Cranbrook, Gillingham, Sevenoaks, Tonbridge, Tunbridge Wells, Kings Hill, West Malling and Rainham
• Phone 01622 741239

Pros

• Long trading history reduces continuity risk on multi-month builds
• Multiple third-party vetting bodies (FMB, KCC Trading Standards, Checkatrade)
• End-to-end project management from pre-start meetings to handover
• Tailors each build to property type, conservation status and access constraints

Cons

• Smaller public Google review footprint than some competitors
• Website occasionally lists outdated coverage areas
• Pricing only provided after a site visit and design discussion

Track record: South East Building Service publicly references a team with more than 100 years of combined building experience and a 25-year FMB-checked trading record, making it one of the longer-established extension specialists in the Maidstone area.

Request a free quote via southeastbuildingservice.co.uk or via its FMB profile.

4. JK Construction (South East) Ltd

Best for: Homeowners who want absolute price certainty up front and a written 10-year structural warranty on their extension.

JK Construction (South East) Ltd is a Maidstone limited company specialising in new builds, extensions, conversions and loft conversions, with a fixed-price quoting model and no upfront deposits.

Key details

• Registered office: 98 Holland Road, Maidstone ME14 1UT (Companies House records incorporation in March 2016)
• Services: new builds, single and two-storey extensions, loft and garage conversions, commercial projects and bar fit-outs
• Fixed-price quotes covering labour, materials and plans
• 10-year structural warranty on completed builds
• Commercial clients reportedly include Maidstone and Pembury Hospitals and Amazon
• Listed on TrustATrader, Checkatrade and FMB

Pros

• Price-match commitment and fixed-price guarantee remove typical scope creep
• 10-year structural warranty is unusually long for the Kent residential market
• No upfront deposits for labour, materials or plans
• Strong commercial track record reassures domestic clients on scale

Cons

• Heavier commercial focus may not suit smaller cottage extensions
• Lead times for new builds can be long
• Less personalised owner-to-client contact than smaller family firms

Track record: JK Construction (South East) Ltd is verifiable on Companies House (company number 10085100) and lists hundreds of completed projects on its own site, including new builds, extensions and commercial fit-outs across Kent and London.

Browse projects and request a quote at jkconstructionsoutheast.com.

5. Total Extensions Kent

Best for: Homeowners chasing a design-led extension with in-house drawings, planning support and a wide menu of glass and orangery options.

Total Extensions Kent is a Maidstone specialist that focuses exclusively on extensions and conversions, offering architectural drawings and planning permission services alongside the build.

Key details

• Based at Merrick, Ulcombe Road, Maidstone ME17 3JE
• Phone 07730 354 804
• Services: house extensions, kitchen extensions, orangeries, garden rooms, glass extensions, garage conversions, loft conversions, structural alterations, new builds
• In-house architectural drawings and planning permission support
• Dedicated area pages for Sevenoaks, Ashford and Tunbridge Wells
• Active Google Business Profile and social channels on Facebook and Instagram

Pros

• Single-focus extension specialist rather than a generalist builder
• Bottom-up design service combining concept and build under one roof
• Strong range of glass and orangery solutions for light-led extensions
• Local case studies on the blog covering Maidstone and Paddock Wood

Cons

• Year founded and team size are not transparently published
• Fewer public reviews on third-party platforms than some rivals
• Premium design service may not suit straightforward rear-only extensions

Track record: Total Extensions Kent maintains a public Google Business Profile and dedicated location pages for Maidstone, Sevenoaks, Ashford and Tunbridge Wells, signalling consistent local SEO investment over multiple years.

Enquire via totalextensionskent.co.uk or the linked Google Business Profile.

6. M Richards Building and Roofing Services Ltd

Best for: Extensions that involve significant roofing work, such as wraparounds, two-storey side returns or loft-with-extension combos.

M Richards Building and Roofing Services Ltd started as a roofing specialist in 1986 and has since expanded into a full domestic building service covering extensions, loft and garage conversions across Kent.

Key details

• Based at 4 Pilgrims Court, High Street, Charing, Kent TN27 0HU
• Phone 01622 734377
• Established 1986 with a roofing focus; building services arm added more than 10 years ago
• 28+ years of roofing experience covering tiled, slate, lead and PVCu
• House extensions, loft conversions, garage conversions, project management and landscaping
• Covers Maidstone, Medway, Sevenoaks, Tunbridge Wells, Sittingbourne, Ashford, Faversham, Aylesford, Snodland, West Kingsdown, East and West Malling, Paddock Wood and Tonbridge

Pros

• Roofing heritage is useful where extensions involve complex roof tie-ins
• In-house tradesmen, electricians and plumbers reduce sub-contracting risk
• Wide Kent coverage including the Weald and Medway towns
• Free, no-obligation surveys and quotations

Cons

• Brand identity is more roofing-led than extension-led
• Limited published case studies of larger two-storey extensions
• Pricing only available after a site survey

Track record: Per its own site, M Richards has put quality first for more than 25 years on extension, loft and decking projects across more than 20 Kent towns, with roots in the regional roofing industry going back to 1986.

Request a free survey at richardsroofing.co.uk or call 01622 734377.

7. Benchmarque Construction Ltd

Best for: Larger refurbishments and rebuilds where premium interior finishes (luxury kitchens, statement bathrooms) are as important as the structural shell.

Benchmarque Construction is a Maidstone-based building company reporting over 30 years of trading and more than 50 years of combined team experience, with FMB membership and a focus on interior-led builds.

Key details

• Based in Maidstone, Kent
• Reports 30+ years of trading; FMB member
• Services: major refurbishments, house extensions, loft conversions, luxury kitchens and bathrooms, hard and soft landscaping
• End-to-end service from planning stage through to completion with in-house project management
• Listed across Yelp UK, FMB and other Kent trade directories
• Known for converting tired buildings and combining two homes into one

Pros

• Long combined experience across the team for complex refurbishments
• FMB membership adds independent vetting
• Strong reputation for interior finishing alongside structural work
• Project management led from planning to completion

Cons

• Public Google review footprint is smaller than some Maidstone rivals
• Better suited to medium and large projects than small porches or rear additions
• Pricing only released after a site visit

Track record: Benchmarque Construction publicly states more than 50 years of combined building experience across its team and over 30 years of company trading, both of which are verifiable via its FMB profile and Yelp UK listing.

Visit benchmarqueconstruction.co.uk or check its FMB profile for vetting details.

House extension FAQ

How much does a house extension cost in Kent in 2026?

In 2026, single-storey rear extensions in Kent typically cost between £1,800 and £3,000 per square metre at standard specification, putting a 20 to 25 square metre extension at roughly £45,000 to £75,000. Premium specifications with bifold doors and structural glass can reach £75,000 to £120,000. Two-storey extensions usually land between £85,000 and £160,000 for 35 to 50 square metres of added space.

Do I need planning permission for a house extension in Kent?

Many single-storey rear extensions in Kent fall under Permitted Development rights, but rules tighten in conservation areas and for properties subject to Article 4 directions. The standard 2026 householder planning application fee is £206, and a Lawful Development Certificate (around 50% of that) is widely recommended to evidence compliance during a future sale. Always confirm with your local planning authority.

How long does a single-storey extension take to build?

Most single-storey rear or side extensions in Kent take between 8 and 16 weeks on site, depending on size, complexity and weather. Industry guidance and quoted builder timelines suggest 8 to 12 weeks for a straightforward single-storey extension and 16 to 20 weeks for a double-storey extension. Wraparounds and structural alterations typically sit at the longer end.

How do I find a reputable house extension builder near me?

Cross-check three independent signals before signing: a Companies House record, third-party vetting (Federation of Master Builders, Kent Trading Standards Checked, Checkatrade or TrustATrader), and verified reviews on Google or Trustpilot. Ask to visit a completed extension, request proof of public liability insurance (typically £2 million) and confirm the deposit and stage-payment plan in writing.

Can I live in my house during an extension build?

Yes, most single-storey extensions can be built with the family in residence, provided the builder partitions the working area and protects access to the kitchen and bathrooms. Larger two-storey or wraparound projects sometimes need short-term decanting, especially during the structural opening-up phase. Discuss site partitioning, dust control and working hours at the quote stage.

What is the cheapest type of house extension in Kent?

A garage conversion is usually the most affordable way to gain habitable space in Kent, typically delivered in around three weeks and built on existing foundations. After that, modest single-storey rear extensions on a permitted-development footprint offer the best cost per square metre, especially if the kitchen and bathroom fit-out are kept to a standard specification.

Choosing the right Kent extension builder

All seven companies on this list serve homeowners across Maidstone and the wider Kent region, but the right match depends on project scale, budget and how hands-on you want the relationship to feel. For larger commercial-style new builds, JK Construction and RJ Construction have the team depth. For interior-led refurbishments, Benchmarque stands out. For roofing-heavy projects, M Richards offers a clear edge.

For most Kent homeowners planning a single or two-storey extension, BDC Construction’s Maidstone-based team remains the go-to choice. The combination of 20+ years of hands-on extension experience, referral-led growth and a single point of contact from quote to handover is rare at this scale. Request a free, no-obligation quote on 01622 946189 or via the BDC Construction website.

Methodology and update note

This list was compiled in June 2026 by reviewing public information published on each company’s own website, FMB profiles, Kent Trading Standards listings, Checkatrade, TrustATrader, Trustpilot and Companies House. Companies were shortlisted on years trading, range of extension services, accreditations, verified reviews, transparency and Kent coverage. Pricing benchmarks are drawn from FMB, Checkatrade and MyBuilder 2026 cost guides for the South East. No company paid to be included.