London & South-East Building Contractors
Extensions, loft conversions, new builds and full-scope structural renovation. One team from first brief to final handover.
What We Build
Calderwood handles every discipline in-house. No coordinating separate trades, no handoff confusion - the same team manages your project from the ground up.
From single-storey kitchen extensions to wraparound side returns with lantern glazing. Structural design, steelwork, insulation and build managed as one project.
Dormer, mansard, hip-to-gable and Velux loft conversions. Party-wall notices, structural calculations, building regs and full interior fit-out included.
Ground-up residential new builds from foundation to full interior finish. We work with your architect's drawings or connect you with a designer we trust.
Underpinning, waterproofing and fit-out of basement voids. We manage structural engineers, tanking specialists and finishing trades through a single contract.
Complete residential gut-outs and restorations. Structural alterations, new layouts, period-appropriate detailing and contemporary interior finishes.
Fitted joinery designed and built in-house: utility rooms, alcove shelving, understairs storage, boot rooms and architectural woodwork across all timber species.
Full bathroom refits, en-suite conversions and wet room installations. Tanking, plumbing, tiling and sanitary ware supply all managed in-house.
Structural openings, kitchen extensions and fitted kitchen installations. We co-ordinate the structural work, electrics, plumbing and cabinetry fit-out.
External render systems, brick repairs, repointing, flashing and fascia work. We maintain the structural integrity of the envelope alongside interior works.
Selected Work
A selection of projects completed across London and the South-East - extensions, loft conversions, new builds and full renovations.
Extension
Rear Extension - Greenwich
Loft Conversion
Dormer Conversion - Lewisham
Loft Conversion
Vaulted Master Suite - Blackheath
Bathroom
En-Suite Conversion - Eltham
Areas We Serve
Based in SE18
About Calderwood
Calderwood Construction was established in South-East London by a team of tradespeople and project managers who were tired of the same story: jobs started by one company, finished by three, with no one accountable for the whole.
We operate as a single point of accountability. One contract, one project manager, one team co-ordinating every trade from structural groundworks to final decoration. Our work is concentrated in the south-east quadrant of London - Greenwich, Lewisham, Bromley and Bexley - where we have built a reputation through the quality of the work and the straightforwardness of how we operate.
Extensions and loft conversions are the core of what we do. We understand the planning process, the structural requirements, the party-wall implications and the details that separate a well-built addition from a problematic one.
Discuss Your ProjectA dedicated site manager runs your project. No chasing trades, no explaining yourself to a new face every week.
We carry structural knowledge within the team. Steelwork, underpinning and load-bearing alterations are not subcontracted to strangers.
We advise on permitted development rights, planning applications and building regulations approval as part of every project brief.
Your quote covers all labour, materials and project management. Costs change only when the scope changes - and never without your agreement.
By the numbers
Drawing ref. CW-SE18
Scale 1:50 · Datum SE18 6QW
Issued Rev. C
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Years building across South-East London
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Projects taken from brief to handover
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0disciplines
Core trades managed in-house, not subcontracted
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Site manager accountable for the whole build
Load-bearing alterations, beam and column design, underpinning and steel installation carried within the team, not handed to strangers.
Calculations commissioned, regs sign-off coordinated, Party Wall notices prepared under the 1996 Act before a wall is touched.
An itemised quote with a build programme issued at survey. Costs move only when the scope moves, and never without your sign-off.
A joint walkthrough closes every project. Each item is logged and cleared before the final certificate and the last payment.
How We Work
A clear, predictable sequence. You know what is happening at every stage, who is responsible for it, and what comes next.
We visit the property, walk through your requirements and assess what the building can structurally accommodate before any pricing is discussed.
A full itemised quote covering all works, materials, programme and payment structure. No hidden allowances, no later surprises.
Planning applications or permitted-development notifications filed, structural calculations commissioned, materials ordered, programme confirmed.
Your site manager keeps you informed at every stage. Weekly progress reports and an open line for any queries or decisions.
A joint walkthrough before we consider the project finished. Every snag addressed before final sign-off and payment.
Client Feedback
Generic first-name testimonials, included as illustrative examples of the type of feedback we receive. Calderwood is a fictional demonstration business.
The rear extension was a big project for us - structurally complex and with neighbours on both sides who needed managing. Calderwood handled it all. The steelwork was done without a drama, the bifolds they recommended are exactly right, and the site was left clean every evening.
We had quotes from four builders for the loft conversion. Calderwood's wasn't the cheapest but it was the only one that itemised everything properly. Eight months on, not a single problem. The dormer looks like it was always there.
We project-managed the build ourselves on a previous property and regretted it. This time we handed the whole thing to Calderwood. The planning took longer than expected but that was the council, not them. The build itself ran to the week.
Common Questions
The questions homeowners in London and the South-East most frequently ask before starting an extension or conversion.
Get In Touch
Whether you are planning a rear extension, a loft conversion or a full house renovation, we will come to site, assess the works and give you a written quote with no pressure and no obligation.
Phone
Our Details
Yard & Main Office
14 Calderwood Street
Woolwich
London, SE18 6QW
Hours
Monday to Friday: 7:30am - 5:30pm
Saturday: 8:00am - 1:00pm
Sunday: Closed
Service Area
London and the South-East. South-east London our core area. Projects taken further into Kent and Surrey on request.