Every project has its own challenges. Sometimes it’s the size, sometimes it’s the tight deadline and sometimes it may be of cultural importance. Our work on Fort Asperen in Gelderland was definitely in the latter category. We helped ensure a leakproof roof as part of the restoration of this 19th century fort. The higher goal? A listing as UNESCO World Heritage Site.

National heritage

Fort Asperen is one of the forts of the ‘New Dutch Water Line’, an inundation zone and part of an important historical defensive line. The major restoration of Fort Asperen follows a decision made in 1999 to preserve this national heritage and apply for a listing as UNESCO World Heritage Site. The fort was built in 1846 and has served several purposes over the past one and a half centuries: from a transit station for people hiding from the Germans during WWII to an art gallery. Since its restoration it has been home to a tavern.

Old and new come together

Trisoplast was used to create a waterproof barrier on the fort’s earthen roof (the historic stone structure leaked), with a total surface area of 1600 m2. The flexible Trisoplast liner with excellent adhesive properties attached easily to the old stone and concrete structures. The 7-centimetre-thick mineral liner joins seamlessly with the beautiful historic building and the earth and greenery laid atop it.