Monotonous neighborhood becomes attractive, sustainable residential area

The Akkerwinde/Boterbloemweg neighborhood in Alphen aan den Rijn is visibly renovating. The very outdated houses - concrete shells with brickwork - are becoming a feast for the eyes. Moreover, they will soon meet the strictest requirements for Nearly Energy Neutral Homes (BENG). The exterior wall insulation system of Sto Isoned BV, installed by IJsselmonde, contributes to this.

The preservation project involves 199 social housing units owned by Alphen aan den Rijn housing corporation Woonforte. "These homes have had our attention for some time," says development project leader Wim van Wijngaarden of Woonforte. "They were monotonous and residents complained about moisture and drafts. At the same time, they are spacious homes that have the potential to last for years to come. So we decided to upgrade them to A++ homes. Zero-in-the-Meter will follow at a later stage, because the central heating boilers are only three years old."

Triassic energetics

Woonforte involved Willems Vastgoedonderhoud and Bloemen Architecten in the project to turn the ambitions into a high-quality sustainable and aesthetic plan. Willems Vastgoedonderhoud thought along in technical and energy terms. "We approach such projects from the trias energetica," explains Willems Vastgoedonderhoud director Sander Willems. "We first ensure that the shell of the houses is good and then look at sustainable energy sources and energy-saving measures. With this in mind, we apply triple glazing and exterior wall insulation. The homes will have ventilation with heat recovery."

"We finish the first floor with polymetric bond stone strips."

Thick insulation layer

The exterior wall insulation will be installed in two ways. For reasons of speed, the longitudinal facades of the two- and three-story houses will be provided with a prefabricated system with insulation from Sto. The end facades of the two- and three-story houses, plus the facades of the single-story houses, will be fitted with Sto's exterior facade insulation system on the job. IJsselmonde, Sto's permanent application company, is applying this system. "The system consists of an adhesive layer containing an insulation package, a fiber-reinforced stress distribution layer and a final finish," said Jacco Oostenbrug of IJsselmonde. "On this job, the insulation layer is as much as 23 and 29 centimeters thick. This causes the end walls to come out a lot further. To counteract this somewhat, we glue the system not to the old exterior wall but to the interior cavity wall."

Stone strips in special masonry bonding

"The final finish reflects the high level of quality of this project," continues Oostenbrug. "We finish the first floor with stone strips in polymetric bond. This masonry bond seems randomly applied, but that is by no means the case! The varied, lively facade appearance is enhanced by the fact that the three-story homes have different brick colors than the one- and two-story homes. We provide the first and second floors of all the homes with stucco."

Satisfied residents

The three-story homes are complete. Work is currently underway on the two-story homes, with the single-story homes to follow. Willems: "In the start-up phase, the planning, coordination and wind- and waterproofing of the three-story homes required extra attention. And because of the corona crisis, the work was temporarily halted. We are now carrying out the work again, at a rate of one home per day." Van Wijngaarden adds, "This is a very large project. Despite the difficult start-up, communication and cooperation have been good. This has helped to ensure that the work is now going according to plan. And what is most important to us: the residents have a beautiful, comfortable home that they are very satisfied with."