House extensions
Rear, side, double-storey and wraparound extensions that give you the space you need without moving.
Find out about extensions
Family-run builders in West London
Extensions, loft conversions and refurbishments across London
A family-run building company based in West London. We build home extensions, loft conversions and full refurbishments for families across London and the surrounding areas.
- Rated 5.0 on Google
- 10 years in the trade
- Fully insured
- 2-year workmanship guarantee
- Limited company since 2019
Your local builder, run by a family
M J Builders (London) Ltd is run by Hardeep Samra and Amarjit Kaur Samra. Most of our work comes from word of mouth: families we have built for, their friends and relatives, and the architects, designers and structural engineers who recommend us to their clients. We think that says more than any advert could.
We take on the jobs that make a real difference to how you live: a bigger kitchen-diner at the back, an extra bedroom and bathroom in the loft, or a complete refurbishment that brings a tired house up to date. Many of our projects combine all three, and we are happy to manage the whole thing from the first visit to the final clean.
What we do
Loft conversions
Hip-to-gable, dormer and rooflight conversions that turn an empty loft into bedrooms, bathrooms or a home office.
Find out about loft conversions
Full refurbishments
Whole-house renovations, from stripping back and structural work through to plastering, kitchens, bathrooms and finishing.
Find out about refurbishmentsRecent work
A few of the homes we have worked on recently. See more on our Our Work page, or follow along on Instagram where we post progress from site.
Completed four-bedroom bungalow, Harrow 
Finished flat kitchen, Mayfair 
Finished bedroom with panelled walls, Mayfair 
Period building in Mayfair where we completed a flat renovation 
Bedroom with dark feature wall, Mayfair 
Kitchen units and worktop fitted, Harrow 
Finished bedroom with downlights, Mayfair 
Living space taking shape in a flat conversion, Lewisham
Project videos
Short clips from our projects. Videos start muted; turn the sound on in the player if you like.
Finished bathroom reveal Finished flat: kitchen, bathroom and living spaces New turf, patio steps and alleyway paving
Why families choose us
- You deal with us directly. You will have the phone number of the people running the company, not a call centre.
- One team for the whole job. Extension, loft and refurbishment in one project, built by our core team of 8 people, working alongside trusted subcontractors, with a project manager as your day-to-day contact.
- We work well with your professionals. Architects, designers and structural engineers regularly refer clients to us, and we are used to building from their drawings and working alongside them on site.
- Free home visits and clear, written quotes. We come and see your home at no cost, price from your drawings and tell you what is and is not included, so there are no surprises.
- 10 years in the trade and fully insured. You are in experienced hands. Fully insured, with public liability and employer's liability cover. Certificate available on request.
- Based in West London, working across London. We are a West London family business and take on work across London and the surrounding areas.
Peace of mind
What you can expect when you work with us.
- Insurance. Fully insured, with public liability and employer's liability cover. Certificate available on request.
- Free home visit and a written quote. We come and see your home at no cost and give you a written quote that sets out what is and is not included. There is no obligation.
- A written contract. Everything is agreed in a written contract before work begins.
- Clear payment terms. A deposit is only taken once the contract is signed and work is starting, and stage payments are agreed with you up front.
- Guarantees. Every project comes with our 2-year workmanship guarantee. Where suitable, we can arrange 10-year structural cover through a third-party insurance-backed policy. We will only offer this where the policy is actually in place for your project.
- Who you will deal with. The work is carried out by our core team of 8 people, working alongside trusted subcontractors. Every client is assigned a project manager as their day-to-day contact.
- Building control sign-off. Where building regulations apply, building control inspects the work at key stages and issues a completion certificate once it is signed off.
- Respect for your home and neighbours. Tidy sites, sensible working hours and consideration for the people next door are part of how we work.
What our clients say
Exceptional Work & Professional Team!
Reliable and high-quality construction services.
Had work done by us? Leave us a review on Google.
Building across London and the surrounding areas
We are based in West London and work across London and the surrounding areas. Places we work in include Southall, Hayes, Ealing, Hillingdon, Uxbridge, West Drayton, Harrow, Greenford, Northolt and Hounslow. Not sure if we cover your area? Just ask.
Thinking about extending or converting your loft?
Tell us a little about your home and what you have in mind. We will get back to you to arrange a free home visit and a free, no-obligation quote.