Independent and strong feat of craftsmanship in Ommoord

'Bats call for flexible phasing'

At Einsteinplaats, Zernikeplaats and Debijeweg in Rotterdam-Ommoord are three imposing ERA flats from the 1960s. IJsselmonde Buitengevelisolatie provided the six end walls with new insulation using the system of Sto Isoned. The facade renovation was carried out in a separate second phase because flora and fauna procedures caused delays. IJsselmonde eventually carried out the work independently - without the intervention of the main contractor.

IJsselmonde knows ERAflats inside out. Jacco Oostenbrug of IJsselmonde: "This is the next series of ERAflats we have tackled. Previously, we also collaborated on the renovation of ERAflats in Rotterdam Alexanderpolder and Capelle aan den IJssel." Yet this assignment was different. Due to delays in the flora and fauna procedures, the facades were not tackled until the interior work and the entrances had already been completed. "We were literally ready to start - trucks full of materials, scaffolding at the ready - when the call came that we were not allowed to start because the bats might not have fled yet due to the bad weather."

Flora, fauna and flexibility

The delay was caused by bats in the cavity walls. "If those are still in the facade, you are not allowed to insulate," explains Jeroen Eijkelboom of ERA Contour. "After all, you then lock them in. That's why we ultimately chose to tackle the end walls in three phases. By keeping four facades accessible to bats each time, they could gradually 'move' from the old situation to the new one: the bat boxes in the new facades." But that took time and patience. After all, bats only fly out during favorable weather conditions, such as dry weather and certain temperatures. It caused the project to be delayed for almost a year and a half. Still, IJsselmonde managed to keep the project tight. "When we were finally allowed to start, we organized everything ourselves," Oostenbrug says. "From scaffolding construction and storage to construction fencing, dirt removal and logistics. Normally the general contractor also has a role in this, but now we were completely self-supporting." The construction site equipment was also provided by IJsselmonde. 

Design freedom

In this type of project, IJsselmonde invariably works with Sto's facade insulation system, the StoTherm Classic system. Mineral facade strips in a carefully chosen color scheme that matches the original character of the flats were applied on top. Niels Kempen of Sto: "They are light, durable and fit in well with the appearance of the flats in the 1970s. The strips have a long lifespan and are also available in numerous colors and textures, which offers a lot of design freedom."

An aesthetic detail about the ERAflats are the horizontal concrete bands that mark the storey floors. "Those are less favorable energetically, but they are image-defining," says Kempen. IJsselmonde has visually reduced those floor edges with 30-cm-wide StoDeco strips. They insulate well and preserve the character of the flats. 

The strips are glued to the facade insulation system and embedded between the mineral facade strips.

Safety first

IJsselmonde also took care of substrate preparation, applied renovation anchors to stabilize the exterior cavity wall and assembled the complete scaffolding structure. Oostenbrug: "With our own team, we controlled the entire process. And that works fine. You know what you're doing ánd that it's done right." For main contractor ERA Contour, this approach was of great value. "We like working with IJsselmonde," says Eijkelboom. "After all, they maintain a tight schedule, think with us and deliver good work. Despite the delay caused by the bats, the quality remained high. And also important: safety, as with us, always comes first."

Comfort for now and later

The flats are owned by housing corporation Havensteder and are part of a broader sustainability project. In addition to facade insulation, the apartments received triple glazing, new window frames and ventilation systems. Residents had to leave their homes temporarily. "Upon returning, they had to get used to their new installations, such as electric cooking and mechanical ventilation," says Eijkelboom. "That's why we put in housing coaches to guide the residents. This way we make sure that everyone not only knows how everything works, but that the new house really feels like a nice home."

For IJsselmonde, the project in Ommoord was yet another confirmation of its craftsmanship as well as flexibility. "We have been involved with the ERA flats for years," concludes Oostenbrug. "Due to the circumstances, this project did have some extra challenges, but then when the scaffolding is finally gone, you can see that it's just right."