Essex GRP manufacturer SGI Composites is marking 30 years in business, having grown from a small composite moulding company into a specialist supplier of access systems, linings, containment and other engineered fibreglass products.
If you’ve ever walked across a GRP walkway at a hospital, stood on an anti-slip platform at a water treatment site or seen composite access equipment on a railway project, there’s a good chance you’ve encountered the sort of work SGI Composites does.
Based on Hythe Quay, the Essex company designs, manufactures and installs glass-reinforced plastic (GRP) and wider fibre-reinforced polymer (FRP) products for customers across infrastructure, rail, energy, utilities, water, defence, marine and automotive.
Much of the work starts with a fairly ordinary problem: a hospital needs safe access across a roof, a water company needs protection against chemicals, or a rail operator needs a lightweight platform that won’t corrode. SGI works through the problem from survey and design to manufacture and installation, with tools such as LiDAR surveying and finite element analysis used on more complex projects.
The business began in 1996, when Ron and Lizzy Stone set up a small composite moulding operation. In those early years, the company worked on specialist linings, flooring and bespoke tanks. Gradually, the range expanded as customers brought increasingly specialised problems to the business.
That led to access platforms and walkways, enclosures, containment systems, trench covers and a growing range of bespoke components.
Some of the company’s product names also have their roots in individual projects. GeoMet came from a bespoke seating job, while Safe Tread developed into a range of GRP anti-slip products for stairs, floors and walkways. Safe Spill followed with GRP spill containment systems.
In 2005, SGI established its own manufacturing facility for grating and anti-slip products. That was an important step in the company’s development, moving it further from its origins as a jobbing moulding business towards manufacturing more of its own products in-house.
Over the years, the company’s work has taken it well beyond Essex. Its published project credits include St Pancras International, Ascot Racecourse, Frimley Park Hospital, Lloyd’s of London, Tesco and Network Rail.
At St Pancras, SGI was involved in a four-year programme to protect historic ironwork, including ultra-high-pressure water jetting to remove hazardous lead-based coatings. The company says the project was worth around £11 million.
More recently, it supplied and installed around 2,500 linear metres of rooftop GRP access infrastructure at Frimley Park Hospital.
Projects like these may be a long way removed from the company’s original moulding work on Hythe Quay, but they still rely on the same basic knowledge of composite materials and the people who work with them.
The business has also changed hands during its 30 years without losing that connection to its manufacturing roots. In 2017, SGI joined Milbank Group, which the company says has allowed it to invest in its people, equipment and ability to take on more complex engineered projects.
Then, in January 2026, Sui Generis International Ltd began trading as SGI Composites. The legal company itself remained unchanged, meaning existing contracts and invoices were unaffected. Its established product brands, including Safe Tread, Safe Spill and GeoMet, also remained in place.
Managing Director Rita Cornwell reflected on the milestone during the company’s 30th anniversary celebrations this month.
“Reaching 30 years is a significant milestone for SGI and a chance to recognise everyone who has contributed to the business along the way,” she said. “Our success has been built on the knowledge and commitment of our team, together with the long-standing relationships we’ve developed with our customers and suppliers.”
She added that the company was continuing to invest in its people, capabilities and more sustainable manufacturing methods, while developing new engineered composite solutions.
That emphasis on experience is particularly important in a business where much of the work is specialised. Trade coverage has highlighted three long-serving SGI employees with more than 75 years of experience between them, while the company has also profiled people who joined as trainees and went on to take on production and operational roles.
For customers, that continuity can make a difference. GRP lining, coating and installation work is not an area where there is much room for shortcuts, particularly when the finished product is being used around chemicals, machinery, vehicles or at height.
The company holds ISO 9001, ISO 14001 and ISO 45001 certifications and lists industry accreditations including Achilles, Constructionline and RISQS.
Sustainability has also become a bigger part of the manufacturing operation.
Since 2022, SGI has used rPET resin made partly from recycled plastic bottles. The company says the process incorporates material from more than one million bottles each year and reduces associated CO₂ emissions by more than 45% compared with conventional resin.
It has also set a target of reaching net zero for Scope 1 and 2 emissions by 2030, alongside measures including LED lighting, hybrid and electric vehicles where practical, and research into materials that can be recycled more easily.
Thirty years on, SGI Composites is a very different business from the small composite moulding company Ron and Lizzy Stone started in 1996. But the basic idea remains much the same: take a difficult i
