Lightweight balconies City Icon are assembled at the very last minute

From balconies, galleries, stairs and landings to columns and complete shells: Granito Concrete Products provides a complete range of precast concrete products. Unique to the range are the BALQOON® balcony systems, which take the precast idea and legolization of construction to the very highest level. The BALQOON®Connect systems are attached to City Icon residential tower in Amsterdam North when the facades are lowered, where architect, structural engineer, contractor and residents benefit from several unique advantages.

Project City Icon is the first project Heddes Bouw & Ontwikkeling is doing with the BALQOON® balcony systems. "The contractor had the desire to build smart," says Ton Tetteroo, director of Granito Concrete Products. "Moreover, in the design by architect Studioninedots, the balconies are not suspended straight above each other, but scattered along the facade. As a result, regular underpinning is not possible. Therefore, the contractor actively sought a system with a disconnected anchorage that does not require underpinning. With BALQOON®Connect, the anchorage is cast along with the main supporting structure of the building. When the facades of City Icon are lowered, the balconies are attached to the main supporting structure without any propping or scaffolding and with just a few nuts and bolts. A simple crane is sufficient for this, which can also save substantially on equipment costs."

More than 3,000 balconies in 30 projects

Granito Concrete Products started developing BALQOON® in 2015 and based on a customer request, says Tetteroo. "We have since completed more than 30 projects with this system, with more than 3,000 balconies produced and assembled. This has not gone unnoticed in the market. From our references, Heddes Bouw & Ontwikkeling also ended up with BALQOON® and Granito Concrete Products. In the preparatory phase, I explained all the advantages of the system in detail. Based on the architectural details, structural principles and facade and frame information, our engineers then modeled the balcony elements in 3D. Once the final shape and weights of the balcony elements were known, we performed the calculations for reinforcement and anchoring and submitted them to the chief structural engineer and municipality." By now, all anchors have been delivered to the project and processed through a special assembly frame, he says. "The prefabricated balconies are produced just-in-time."

Smart, fast and efficient

"With BALQOON® you can engineer in the same way as with a traditional balcony," Tetteroo emphasizes. "This allows us to very easily convert projects conceived and designed in a traditional way into smart, fast and logistically efficient construction methods. The prefabricated balconies can be attached to the main supporting structure at any time. Both at a very early stage and just before the building is completed. From the outside, you cannot see that it is a special balcony system. The only difference is that the anchoring is cleverly integrated into the precast balcony."

If desired, the balconies can be delivered including fencing. However, this was not chosen in this project. "For City Icon, we manufacture and supply 65 hollow balconies, measuring 2.88 x 1.675 and 2.88 x 1.71 meters, which are attached to the facades with only two anchors," said Tetteroo. "The balconies are composed of a bottom plate with rib structure and a concrete cover tile (tread). Because the hollow balcony drains internally, a completely flat transition from the house to the outside can be made. The balcony is completely free of upstands, thresholds and gutters, making it also suitable for the elderly and wheelchair/rollator users. Residents can benefit from maximum user surface area, while the system is also significantly lighter than standard balcony and gallery slab systems. As a result, the foundation can be made lighter. In addition, significant savings can be made on raw materials."

Follow-up Project

In addition to BALQOON® balcony systems, Granito Concrete Products has supplied various stairs and stairwell walls for City Icon. Following on from the Amsterdam residential tower, the precast concrete manufacturer has been awarded the engineering, production and assembly of BALQOON® balcony systems for Biesbosch residential tower in Amstelveen. In this Heddes Bouw & Ontwikkeling project, a new system with solid concrete slabs was chosen, which are also fixed to the building invisibly and with minimal anchoring.