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Building work done properly — from the ground up.

Extensions, refurbishments, conversions and groundworks across South East London, North Kent and Northamptonshire.

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Fixed written quotations

Building regulations handled for you

Written workmanship guarantee

Fully insured — [£X million] public liability

Registered company no. 16872571

A builder who tells you the price — and sticks to it.

Choosing a builder is about more than finding the lowest price. It is about finding a team you can trust to communicate clearly, manage the work properly and deliver what was agreed.

Every Astonmart World project starts with a free site visit and a fixed written quotation setting out the scope of work, proposed programme, materials, exclusions and payment stages.

No vague estimates. No unclear costs. No unnecessary surprises halfway through your project.

Our site operations are led by an experienced Contracts Partner, while our accounts are managed by a qualified accountant. This means your project is properly coordinated on site and professionally managed behind the scenes.

What we do for homeowners

From creating additional space to completely transforming an existing property, we provide practical building solutions tailored to your property and requirements.

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Extensions & Alterations

Create more space without moving. We deliver single- and double-storey extensions, kitchen extensions, garden rooms, open-plan alterations and structural modifications, all carefully planned around your home.

Architecture, research and laptop with black man in warehouse for engineering, building and design. Technology, planning and digital with face of contractor for project management and graphic

Refurbishments & Conversions

Transform and modernise your property with professionally managed refurbishments and conversions, including kitchens, bathrooms, whole-house renovations, garages, basements, barns and self-contained living spaces.

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Groundworks & Exterior Works

From foundations, excavation and drainage to driveways, patios and site preparation, we provide reliable groundworks and exterior services to create a strong foundation for your project.

What we do for professional clients

We also work with insurers, loss adjusters, landlords, letting agents, developers, housebuilders and main contractors.

Our professional services are structured around reliable communication, accurate pricing and properly supervised delivery.

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Insurance Reinstatement

We provide responsive reinstatement services for insurers, loss adjusters and property owners following insured damage. From prompt site inspections and detailed quotations to authorised repairs, snagging and final handover, we keep projects moving while maintaining clear communication with all parties.

Architecture, research and laptop with black man in warehouse for engineering, building and design. Technology, planning and digital with face of contractor for project management and graphic

Subcontract Packages

We provide reliable, supervised subcontract services for housebuilders, main contractors and developers. Our capabilities include groundworks, brickwork, blockwork, carpentry and general building works, delivered with appropriate site supervision, safety procedures and clear coordination with the principal contractor.

Man, construction and tablet with phone call at site for project management or building logistics. Male person and engineering worker talking on technology at industrial architecture design

Landlords & Letting Agents

We support landlords and letting agents with practical building, maintenance and refurbishment services to keep properties safe, functional and ready for occupation. From repairs and remedial work to kitchen and bathroom upgrades, internal alterations and void-period refurbishments, we help minimise delays and maintain property standards.

Why choose Astonmart World

Fixed Written Quotes

Every quotation is based on a proper site assessment and clearly sets out the agreed scope, labour, materials, exclusions and proposed programme.

Clear Payment Stages

Payments are linked to clearly defined project milestones, with the final payment due following completion and snagging.

Building Regulations Managed

We coordinate building control requirements, inspections and completion documentation where applicable, helping to keep the project compliant and properly documented.

One Named Contact

You will have a clear point of contact throughout your project, making it easier to ask questions, receive updates and keep track of progress.

Safety on Every Site

We take site safety seriously, using appropriate risk assessments, method statements and suitably qualified and carded operatives where required.

Workmanship Guarantee

Our work is supported by a written [X-year] workmanship guarantee, together with a defined snagging and aftercare process.

How it works

1. Free Site Visit

We visit your property to understand your requirements, assess the site, take measurements and discuss what you want to achieve.

2. Fixed Quotation

You receive a clear written quotation covering the agreed scope, exclusions, proposed programme and payment stages.

3. Professionally Managed

Once approved, the work is planned and supervised with appropriate health and safety procedures, site coordination and regular progress updates.

4. Sign-Off & Handover

Once the work is complete, we carry out snagging, coordinate the relevant building control sign-off and provide the appropriate completion documentation and certificates.

Areas We Cover

South East London and North Kent — Bromley, Orpington, Bexleyheath, Sidcup, Eltham, Lewisham, Greenwich, Croydon, Dartford, Sevenoaks, Beckenham, Petts Wood, West Wickham — and Northamptonshire and the East Midlands, including Northampton, Rushden, Wellingborough, Kettering, Towcester, Daventry, Blisworth and the Milton Keynes borders.

Planning a Project? Let's Talk It Through.

Whether you are considering an extension, refurbishment, conversion, groundwork project or property improvement, we would be happy to discuss your plans.

Tell us what you have in mind and arrange a free site visit. We aim to respond to enquiries within the same working day.

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