Multifunctional surface
Every part of the roof contributes. Rainwater is buffered and nature is given room to grow.
AMPO’s Lightweight Green Roof Manages 60% Rainwater
AMPO Group, a global leader in stainless steel and alloy castings, expands with a new machining facility in Idiazabal. The innovative building boasts a 6,000 m² Sempergreen Sedum-mix green roof and aims to achieve the prestigious LEED Gold sustainability certification.
Climate adaptive design
The roof stores water during heavy rainfall and helps cool the surroundings during summer heat.
Biodiversity in the built environment
A diverse planting plan attracts pollinators, birds and native insects. This turns the roof into a thriving ecosystem.
Industrial scale sustainability
The new machining facility of AMPO Group is more than just an expansion of production space, it is a statement of intent. Designed with sustainability at its core, the building features a 6,800 m² Sempergreen green roof. For this heavy industrial player, the decision to invest in green infrastructure underlines AMPO’s belief that environmental responsibility and industrial leadership must go hand in hand.
The Lightweight Green Roof System made it possible to install a living roof even on metal spans with strict weight limitations, without compromising performance.
A roof that works hard
The Urbanscape Premium High Green Roof system is engineered for performance. With the capacity to retain up to 45 litres of water per square metre, the roof is able to capture around 60% of yearly rainfall in Idiazabal’s climate. This significantly reduces pressure on local sewage systems and helps mitigate flood risks.
Cooling the roof, cooling the hall
Just as important as water retention is the impact on temperature. Independent studies on the AMPO roof show that surface heat is reduced by more than 20°C during peak summer. That cooling effect doesn’t just benefit the wider environment, it also lowers heat transfer into the production hall itself, creating a more stable and comfortable indoor climate for employees and reducing the need for artificial cooling.
Project Brought to Life By
Engineered with Urbanscape Green Roll
At the heart of the Lightweight Green Roof system lies the Urbanscape Green Roll, a unique substrate layer made of long rock mineral wool fibres. This compact, dimensionally stable felt is designed without binders and delivers exceptional water absorption while staying remarkably light. It acts as a capillary sponge: during rain showers it soaks up large volumes of water, then slowly releases it to the Sedum vegetation above.
The result is a healthy growing medium with high thermal and acoustic performance, strong fire resistance, and long-term sustainability. For AMPO, it was the perfect fit: a substrate layer that combines technical reliability with ecological value.
Why lightweight matters for industrial roofs
Many industrial halls, warehouses and production facilities face strict weight restrictions due to their large spans and metal roof constructions. Traditional green roofs are often too heavy to be considered, especially when saturated with water.
That’s where the Sempergreen Lightweight Green Roof system proves its value: it delivers all the ecological and economic benefits of a green roof- from stormwater retention to cooling – without overloading the structure. This makes sustainable roofing not only possible but practical for buildings that would otherwise miss out on greening opportunities.
Aligned with climate goals
For AMPO, the green roof is one piece of a much bigger sustainability puzzle. The company has an ISO 14001-certified environmental management system, a detailed decarbonisation plan, and is a member of the European Hydrogen Alliance and the Basque Hydrogen Corridor. Their commitment stretches across the value chain: from helping clients reduce emissions through innovative casting solutions to electrifying their own processes and sourcing renewable energy. By integrating a green roof, AMPO ensures its production facilities don’t just meet today’s standards but anticipate tomorrow’s.
The Sempergreen Sedum blankets extend roof life up to three times
Business case for industry
Green roofs on industrial facilities make sense beyond the environmental benefits. By protecting the roof membrane from sun, rain and wind, the Sempergreen Sedum blankets extend roof life up to three times. They also reduce the need for cooling in summer, which translates directly into energy savings for air conidtioning. In Idiazabal, this makes the plant more resilient and more cost-efficient in the long run, proving that sustainability and profitability are not opposites, but partners.
Products we used in this project
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