Durable facades with individual expression

Comfortable apartments with eye-catching stepped gables and spacious balconies. Varied four-story waterfront homes, with private parking in the basement. And spacious villas where you can enjoy the green surroundings in luxury. With the Kloppend Hart project, Alphen aan den Rijn has added a lively and future-proof part of the city. The facades, most of which were created with ceramic stone strips, contribute to this.

Kloppend Hart is the final piece in the development of the Kerk & Zanen neighborhood in Alphen aan den Rijn. The residential area provides space for 76 homes, consisting of sixteen villas, twenty waterfront homes and forty apartments spread over two buildings. Sustainability and comfort are of paramount importance. Including a geothermal heat pump, solar panels and high-quality insulation, the homes achieve an EPC value of zero. 

Own appearance

Studio VVKH made the design for Kloppend Hart. Within the contours of the planning area, they gave form and content to the houses. "Our design vision is particularly grafted on the view of the Green Heart," says architect Ronald Knappers. "At the apartments, this led to ideally oriented, spacious terraces, partly executed in loggia style, partly as complete outdoor space. Through the composition of terraces and massing, we gave each apartment its own appearance. The water houses and villas have the same formal language and individual expression, with the water houses being a true party. Each dwelling is different, both in terms of facade appearance and layout. Some have an extension, others are equipped with a practice room. Or they have an enlarged rear and a loft on the second floor."

Ceramic stone strips 

The starting point for the design of the facades was to be constructed of a cavity wall and traditional masonry. However, this proved to be a difficult task in practice. Director Ron Blom of BM van Houwelingen, the construction company that realized the Kloppend Hart homes, explains, "The application of masonry is labor-intensive and requires craftsmanship. In these times of staff shortages, it is very difficult to have enough good masons. As an alternative, we suggested to the architect that the apartments and waterfront houses have exterior wall insulation finished with ceramic stone strips. We have good experience in this area, in new construction and renovation projects, with IJsselmonde. It specializes in the installation of exterior wall insulation systems from Sto Isoned." Knappers adds, "That was a bit of a gulp for us. Knocking Heart is a typical masonry project where the brick is very important. We even already had a brick in mind. Nevertheless, we decided to go along with the contractor's proposal. In particular, the environmental aspect was the deciding factor. The manufacture of stone strips releases much less CO2 than masonry bricks."

From golden yellow to oxide red

"Via IJsselmonde, we were involved in the project to help think about the ceramic stone strips to be applied," explains Sto's project manager Niels Kempen. "In consultation with the architect, the contractor and IJsselmonde, we chose an extruded strip in (DF) German size 240 x 52 x 14 mm from our StoBrick PO series. These stone strips are produced at our sister company in Germany. Manufactured from Westwalder clay, they are very strong, allowing them to be realized relatively thin. In addition, this brick strip has an extremely low water absorption. This promotes color retention and makes the strips resistant to frost." From the six color series of the StoBrick collection, four colors from the StoBrick PO series were chosen: golden yellow, ochre yellow, carbon gray and oxide red. Kempen: "The exterior wall insulation package to which these stone strips are applied is StoTherm Vario. This insulation system is composed of an adhesive layer, an insulation package and a cement-based mortar fabric layer."

Thorough preparation

The fact that the facades were converted from cavity walls with traditional masonry to exterior facade insulation with ceramic stone strips was quite a challenge in terms of engineering. "That engineering was up to us," says Jacco Oostenbrug of IJsselmonde. "Among other things, we had to deal with different insulation thicknesses, ranging from 16 to 25 centimeters. That thick layer of insulation was necessary to achieve the sustainability ambitions. Another point of attention concerned the individual appearance of the facades. This required thorough preparation, and we had to have a very clear idea of how many stone strips we needed of each color. Given the scarcity of materials and long delivery times, reordering later was not an option."

Vakwerk

"Our biggest concern was that we would be short of stone strips," adds Bas Boere of IJsselmonde. "Because of good preparation, we prevented this and kept the work progressing. One circumstance we had less control over was the wind. It played a particular role in the construction of the stepped gables. In terms of planning, we had to allow for extra assembly time because we were grouting ceramic stone strips on site." Knappers adds: "The team at IJsselmonde delivered craftsmanship. The stone strips are on nicely, much tighter and with fewer tolerances than traditional masonry. At the same time, you can't see with the naked eye that they are stone strips. I am very satisfied with the end result and convinced of the possibilities of stone strips. Especially with sustainability in mind, this facade finish has the future."