Home Extensions & Conversions Across Hertfordshire
Now based in Stevenage (formally Potters Bar), we design and build high-quality extensions and loft/garage conversions across Hertfordshire — with clear communication and quoting, expert sequencing and management, and a finish you’ll be proud of.
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Established 2010 • Transparent quote break-down • Project-managed builds
Services
Extensions And Conversions
We specialise in the design and construction of high-quality house extensions and conversions, delivering well-planned builds that add meaningful space and long-term value to your home.
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From groundwork, drainage and structural alterations to steelworks, roofing, and final finishes, we manage the entire build process from start to completion — ensuring every stage is coordinated, compliant, and built to a consistently high standard.
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Our experienced team handles complex projects including single and double-storey extensions, loft and garage conversions, and major structural reconfiguration, with careful attention to sequencing, detailing and site management throughout.
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This single-storey extension project involved full structural works and internal integration, delivered as a complete end-to-end build by JB Carpentry Plus Ltd.
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Get in touch to discuss your extension or conversion project.
Expert Renovation And Remodelling
As part of larger extension and conversion projects, we deliver carefully planned renovation and remodeling works that improve the flow, function and overall use of space within the home.
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With a strong background in structural alterations, internal reconfiguration, and first and second fix works, our experienced team manages all stages of the build — ensuring structure, layout and finishes are fully integrated rather than treated as separate trades.
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By coordinating the full scope of works under one contract, we provide clients with a smooth, well-organised build process and a finished home that feels cohesive, practical and purpose-designed from start to completion.
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Get in touch to discuss your renovation or remodeling project as part of a larger build.
Gallery
"From start to finish, JB Carpentry Plus provided us with an exceptional service"
About us
JB Carpentry Plus Ltd is a Hertfordshire-based building company specialising in high-quality house extensions and conversions, delivering well-planned residential projects from initial concept through to completion.
Established in 2010, we focus on projects that require careful coordination, structural understanding and attention to detail, bringing together all elements of the build under one managed process. This approach allows us to deliver homes that feel cohesive, practical and purpose-designed — not simply extended or altered as an afterthought.
By managing the full scope of works in-house, we provide clients with a single point of responsibility, clear communication throughout the build, and confidence that every stage is delivered to a consistently high standard.
If you’re planning an extension or conversion project in Hertfordshire, we’d be happy to discuss how we can help.
"The longer I live, the more beautiful life becomes.
If you foolishly ignore beauty, you will soon find yourself without it.
Your life will be impoverished.
But if you invest in beauty, it will remain with you for all the days of your life."
Frank Lloyd Wright
Beautifully designed homes — built with purpose
Thoughtful design and meticulous execution come together to transform not just space, but the way you live in it.