The upgrade has increased roll, slab and blowing wool capacity by up to 25,000 tonnes, added new product capability, and further reduced the embodied carbon of products made at the site.
Knauf Group general partner Alexander Knauf and Liverpool City Region mayor Steve Rotheram, alongside representatives from St Helens Borough Council and senior personnel from the Knauf Insulation Group, officially reopened the plant.
Neil Hargreaves, managing director, Knauf Insulation Northern Europe, said: "Glass mineral wool insulation is central to meeting the UK's housebuilding and energy efficiency needs.
"This upgrade means we can deliver increased volumes and enhanced products for our customers to meet rising demand for warmer, safer and sustainable homes with lower energy bills."
The plant now features UK-first forming technology that will enable Knauf Insulation to create the next generation of low thermal conductivity, non-combustible glass mineral wool products and add thicker options to its existing ranges.
The programme of work involved more than 1,100 contractors over a six-month period.
Steve Rotheram added: "I've really enjoyed the visit and the tour of the new facilities. What it shows is a real demonstration of confidence, not only in the product or even in the process, but in the people of this area. St Helens is famous for glass. With a facility like this we're going to be right at the forefront of investment and the economic growth that stems from it. It's great for the City Region."
