Business Details
37 Years
experience
Expert Loft Conversions & House Extensions in North London
At Cox Format Developments, we have dedicated over 35 years to mastering the art of residential construction across North London and Hertfordshire. Our expertise in loft conversions and house extensions is built on decades of hands-on experience, allowing us to navigate local planning regulations with precision while delivering tailored solutions for homeowners. We pride ourselves on transparent pricing, fixed-scope contracts, and a commitment to quality, ensuring no hidden extras or compromises on materials. Our team of skilled craftsmen, many trained through our apprenticeship programme, delivers projects with meticulous attention to detail, backed by comprehensive guarantees and full insurance coverage.With a reputation sustained through personal recommendations and Which? Trusted Trader status, we combine technical proficiency with a client-centric approach, managing every project from initial consultation to final completion. Our focus remains on transforming homes efficiently, with minimal disruption, while maintaining open communication and adherence to agreed timelines. This enduring dedication to excellence has cemented our position as a trusted local partner for homeowners seeking to enhance their living spaces.
Services
Loft Conversions
House Extensions
Home Finishings
Planning Applications
Structural Advice
Kitchen Extensions
Dormer Conversions
Roof Conversions
Party Wall Services
Details
- Year established: 1989
Highlights and features
- 35 years of specialist experience in North London loft conversions and extensions
- Directly employed tradespeople trained through our apprenticeship programme
- Fixed-scope contracts with guaranteed pricing and no hidden extras
- Award-winning customer service with Which? Trusted Trader accreditation
- Comprehensive planning and structural advisory services included as standard
Associations and certifications
- Which? Trusted Trader
What people say
Reliable and trustworthy
Transparent pricing
High-quality work
Stress-free service
Excellent communication
Services
Loft Conversions
Specialist loft conversions transforming unused spaces into luxury living areas. With 35 years' local expertise, we handle full project management including planning permissions, structural calculations, and building control sign-off. Our fixed-scope contracts guarantee no hidden extras while maintaining premium material standards. Completed projects typically increase property value by 20-30% while avoiding the need for relocation.
House Extensions
Custom house extensions maximising living space without compromising existing property value. Our design-build approach incorporates structural engineering, party wall agreements, and local authority compliance. Projects include single/double storey options with guaranteed pricing and transparent payment schedules aligned to project milestones. Completed extensions typically achieve 95%+ client satisfaction through minimal disruption and fixed timelines.
Planning Applications
Full planning permission support for conversions and extensions. Our team prepares detailed architectural drawings, submits local authority applications, and manages objection resolution. With 98% approval rates across North London boroughs, we streamline the process while maintaining compliance with building regulations and conservation area requirements.
Home Finishings
Complete interior finishing services complementing structural projects. Our craftsmen deliver bespoke plastering, carpentry, and decorating using premium materials. The process includes space optimisation advice and coordinated scheduling with main build timelines to ensure seamless project completion without additional disruption.
Kitchen Extensions
Tailored kitchen extension solutions integrating structural work with functional design. Includes free kitchen design service, utility relocations, and coordinated trades. Projects feature guaranteed fixed pricing with optional trade discounts on cabinetry. Completed spaces prioritise natural light optimisation and workflow efficiency while maintaining structural integrity.
People
Peter Maton
CEO
With over 35 years in the construction industry, Peter established Cox Format Developments' reputation for integrity and quality. He oversees strategic direction while maintaining hands-on involvement in complex projects.
Mark Rossi
Project Manager
Leading projects since 2012, Mark specialises in coordinating multi-phase builds. His expertise in party wall legislation and local planning ensures smooth project execution from inception to completion.
James
Site Foreman
As lead site supervisor for 15+ years, James manages daily operations with emphasis on quality control. Recognised for exceptional client communication and team leadership during complex loft conversions.
Questions
What areas do Cox Format Developments cover?
We operate across North London including Barnet, Enfield, and Hertfordshire, with over 35 years' experience in local planning requirements and building regulations.
Do loft conversions require planning permission?
Many loft conversions fall under permitted development, but we handle all planning applications, building control approvals, and party wall agreements as standard.
How long does a typical extension take?
Single-storey extensions typically complete in 8-12 weeks, while double-storey projects take 12-16 weeks, including necessary preparation and finishing works.
What guarantees do you offer?
All projects include a 10-year structural warranty, 2-year guarantee on finishes, and full insurance coverage throughout the build process.
Can you help with financing options?
Yes, we provide guidance on home improvement loans and can connect you with trusted financial partners offering competitive rates for building projects.
Are your prices fixed throughout the project?
We provide fixed-scope contracts with guaranteed pricing - no hidden extras or unexpected charges without your prior written approval.
Reviews (3)
Tony Walker
Jan 28, 2022
Report
Positive:Professionalism
Great service, job well done. Highly recommended
Service:Repair water fixtures
Great service, job well done. Highly recommended
Service:Repair water fixtures
Jamie Needcraft
Sep 29, 2020
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After several glowing recommendations from business acquaintances about work that Cox Format had undertaken for them, and finding I needed a new roof too, we booked a consultation with Peter Maton the CEO. Peter visited us with Mark Rossi who was to become our Project Manager. With both, their experience and professionalism was immediately evident and reassured us from the start. One of the things that really sets Cox Format apart is that they deal with the job from startto finish. They designed the loft along with all structural elements, and dealt with the council’s Planning and Building
Kate Pidgeon
Feb 22, 2017
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We have now used Cox Format on 3 separate occasions over many years to carry out loft conversions and kitchen extension. They have consistently worked to a very high standard. In addition to great workmanship (with zero snagging / problems) they are timely, polite and courteous, and they respond to any queries / issues very promptly. Highly recommend.
