Written by Mark Reid,
Trades Editor ·Verified 23 September 2026
Beckenham's mix of Victorian terraces, 1930s semis and post-war family homes near Kelsey Park and Foxgrove means builders here need a fair range of skills. A loft conversion in a bay-fronted terrace off Croydon Road throws up different problems to a rear extension on a semi near Eden Park, and anyone who's had scaffolding up in Beckenham will know party wall agreements with neighbours come up a lot given how close the houses sit together. Local builders also deal with clay soil across much of the borough, which matters for foundations and underpinning work, so it's worth finding someone who already knows the area rather than starting from scratch.
The businesses listed here are pulled from public business listings and ranked mainly by review rating and how many reviews they've built up, with a small boost for those showing a working website and phone number. We check each firm's homepage to confirm building work, extensions, renovations or general construction, is actually their main trade, which stops plumbers, electricians and other unrelated trades slipping onto a builders page. Listings flagged as permanently closed get removed automatically as part of that process. Where you spot a Trust Verified badge, that particular business has gone further and passed our full verification, covering trade qualifications and accreditations, public liability insurance, trading history, customer review history and registered company details. Our How We Verify page sets out exactly what's involved. Businesses without that badge haven't been through that process with us, so it's down to you to check things like insurance and accreditation before you commit.
Before hiring anyone, ask to see proof of public liability insurance and, if the job needs it, confirmation they're registered with a relevant trade body such as the FMB or a competent person scheme for building regulations sign-off. For anything structural, like removing a load-bearing wall or building an extension, ask whether building control has been notified and who's applying for the completion certificate. Get at least two or three written quotes rather than relying on a single verbal estimate, and ask each builder for photos of similar jobs they've completed nearby. It's also worth asking about their usual working hours and how they handle waste and skip permits, since parking and access can be tight on some of Beckenham's narrower residential streets.
How We Select & Rate The Best Builders in Beckenham
Ranking is driven mainly by review rating and review count from public business listings, with a small lift given to businesses showing a working website and phone number. We check each business's homepage to confirm building work is what they primarily do, which keeps unrelated trades off the page. Listings marked permanently closed are removed automatically. Businesses displaying a Trust Verified badge have additionally passed our full verification, covering trade qualifications and accreditations, public liability insurance, trading history, customer review history and registered company information; see our How We Verify page for the full detail. Other businesses listed here have not been independently verified by us, and appearing on the page isn't 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 →
Residential and commercial building work in Beckenham is the focus for Glenn Miller Builders Limited, a firm operating under the BR3 4SB postcode. The company covers construction and general building contracts, working across the local area and surrounding neighbourhoods. More detail on their services and current projects is available at gmbltd.co.uk.
General building work across Beckenham and the surrounding area is the focus for Cromarty Construction Limited. The company takes on residential and commercial projects, covering the range of work typically expected from a local builder. BR3 4RH places them well for homeowners and businesses across this part of south-east London.
Building work across Beckenham and the surrounding area is the focus for Rutland Building Ltd, a contractor taking on residential and commercial construction projects. The company operates from the BR3 postcode, giving it a practical base for local builds, extensions, and structural work. Straightforward in its scope, it offers the kind of general building services that homeowners and small developers in south-east London regularly require.
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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A single-storey rear extension typically runs from around £1,800 to £2,600 per square metre depending on specification, while a loft conversion with a dormer often lands between £45,000 and £65,000 in this area. Smaller jobs like a garden wall rebuild or internal wall removal might cost £1,500 to £4,000. Prices vary with material choices, access difficulty on terraced streets, and whether structural engineering or building control sign-off is needed. Getting two or three quotes is normal practice and lets you compare not just price but what's actually included.
Do I need planning permission for an extension in Beckenham?
Many single-storey rear extensions fall under permitted development rights, but this depends on the size, how close you are to a boundary, and whether your property is in a conservation area, and parts of Beckenham near Kelsey Park do have conservation area restrictions. Loft conversions with dormers usually need planning permission if they face the street. A good builder or architect will check this with Bromley Council before work starts, and it's worth confirming who's responsible for submitting the application.
How long does a typical extension or loft conversion take?
A single-storey extension usually takes eight to twelve weeks from groundwork to completion, weather and material delivery permitting. A loft conversion with a dormer often takes six to ten weeks. Add extra time if you're waiting on bespoke joinery, planning decisions, or if the property needs underpinning because of the clay soil common across this part of London.
Should I use a builder who's registered with a trade body?
It's worth it where you can. Membership of bodies like the Federation of Master Builders or TrustMark means the builder has met certain standards and often comes with access to warranty schemes covering the work for a set period. It's not a legal requirement, so plenty of good local builders work without it, but ask about workmanship guarantees either way and get them in writing.
What's the difference between a quote and an estimate?
A quote is a fixed price for agreed work and materials, while an estimate is a rough figure that can change once the job's underway. Always ask which one you're being given before signing anything, and make sure the paperwork lists materials, labour, waste removal and a rough timeline so there's less room for disputes later.
How do I choose between builders on a list like this one?
Start by reading recent reviews rather than just the star rating, since patterns in complaints (missed deadlines, poor communication) tell you more than a single bad review. Ask to see photos of finished jobs similar to yours, ideally nearby in Beckenham or Bromley, and request references you can actually call. Confirm public liability insurance is current, check whether they're registered with a competent person scheme if building regulations apply, and look up their company registration if they operate as a limited company. If a business carries a Trust Verified badge on this page, that's been checked as part of our full verification process; for anyone without it, treat these checks as your own responsibility before signing a contract.
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