About us

Working in partnership with our clients, designers and supply chain, our collaborative approach is key to the way we operate


Gary Cosgrove, MD.

In our experience, one size rarely fits all. That’s why we offer a personal, collaborative approach to your project, no matter how big or small.

We’re a family business, which means we understand the value of one-to-one communication, and taking the time out to understand the ins and outs of your project. Our relationships with our clients are hugely important to us – from local authorities to commercial or domestic clients, we’re trusted to advise on the most cost-effective and high quality solutions, and to deliver projects on budget and on time..

For us, personal service is also about being flexible – we can work as part of your project team to provide high quality construction of refurbishment, or we can offer a package deal solution that covers everything from land finding to design, planning and building. We can also help you with everything in between – why not get in touch, and talk to us about your plans?

Pictured: John Cosgrove (standing) at Llanedeyrn 1972

The methods have changed but the principles remain the same.
Pride in the job… always


Gary Cosgrove, MD.

We’re proud to be a family construction business - we’ve been working with clients across South Wales and beyond for 50 years.

M&J Cosgrove was founded by Jack and Marlene Cosgrove in 1968 – they started out building council houses, and soon grew their business into one of the leading construction companies in South Wales, with a portfolio of award-winning construction, refurbishment and development projects for local authorities, health authorities, retail, commercial and domestic clients.

Jack and Marlene’s son Gary took over the running of the business in 1994, and the family values upon which the business was founded endure to this day - building collaborative relationships with our clients, delivering a personal, one-to-one service, and putting quality and service at the heart of everything we do.

From conception to completion, we can turn your ideas into a reality


Gary Cosgrove, MD.

Looking for a team who can get involved from the very start, offering advice and services like land finding, design and planning? You’ve come to the right place.

One of the benefits of having 50 years’ experience in construction is that we know the market inside out, and we’re in a great position to bring our knowledge to your project, whether it’s advising on best value materials or managing everything for you. We believe that early involvement is the best way to ensure your project runs smoothly; if required, we can provide an all-inclusive package deal that includes consultation, design, land finding, development, construction and conservation.

This is a hugely cost-effective option – unlike an architect, our priority is your budget, and ensuring we deliver a design that meets your needs. It’s also a more efficient way of working, with a single project management team, one point of contact and a seamless transition from start to finish.