184-home retrofit makes history

Belgian association Woonpunt Zennevallei chose the Knauf Energy Solutions renovation package because it was low risk in terms of future maintenance and met regional Flemish energy performance and decarbonisation standards

Knauf Energy Solutions (KES) has completed the biggest ever large-scale real-performance deep retrofit in history — a total of 184 homes for social housing company Woonpunt Zennevallei, benefiting hundreds of residents in the Vogelweelde Estate in the Belgian town of Halle.

The energy saving results of the giant project will be announced in early 2022, but already improvements of 26% have been recorded by KES negawatt hour technology following the quality installation of Knauf Insulation loft systems alone.


Why was KES selected?

Woonpunt Zennevallei chose KES to carry out the large-scale renovation because it wanted a solution that was able to show the real energy savings achieved by the renovation and then deliver those savings backed up by a warranty. The approach of KES is based on providing objective real time data rather than theoretical calculations. This verification of real performance was critical to Woonpunt Zennevallei because it demonstrated that quality products were installed to a high standard of workmanship and trustworthy quality controls were in place.


How was the scale of the work decided?

Prior to the renovation, KES monitored a range of buildings for three months to assess the baseline energy performance of each home type with state-of-the-art technology and cloud data algorithms. Using this data, the company was able to demonstrate a range of achievable energy savings based on four potential renovation scenarios.

Director of Woonpunt Zennevallei Bart Vranken says: “This was the most detailed analysis ever presented to us for the comparison of renovation packages.”


Which renovation package was selected?

As a result of the analysis, Woonpunt Zennevallei chose a cost-effective renovation package which was low risk in terms of future maintenance and met regional Flemish energy performance and decarbonisation standards. These standards for residential properties are aligned with the European Union’s ambition to be the world’s first carbon neutral continent by 2050.


What work was carried out?

The work started in 2019 and was completed by the end of June 2021.

The renovation included ventilation and heating upgrades alongside the installation of high quality Knauf Insulation loft systems with membranes, tape, cavity wall insulation and Knauf Insulation external wall systems from Czechia to improve the thermal performance of solid upper walls.

Quality was controlled and tracked using KES apps to present photographic evidence at every stage of the renovation to the project manager, schedule workflow, provide best practice descriptions at every step, ensure efficient communication with residents, schedule follow-ups and provide detailed work reports.


What were the challenges facing the project?

The project featured 20 different building archetypes meaning 20 different renovation packages. KES provided a range of energy renovation options to meet the needs of the housing association.

An important priority of the association was the installation of loft insulation before the end of 2019 ahead of the other renovation work. To achieve this, roof repairs had to be carried out on many of the buildings first.

In addition to the challenges of the pandemic, which resulted in periods of stop-start work, it was essential that the residents remained in their homes while the renovation was carried out to avoid putting pressure on other areas of the housing stock.

This meant that the health, safety and well-being of residents was paramount during the renovation and strict standards of conduct were applied to everyone on site supported by outstanding resident liaison at every stage.

Woonpunt Zennevallei’s Director Bart Vranken described the level of resident engagement as “something that we have never seen before”.

To celebrate the completion of the work at the end of June, KES organised an ice-cream event to thank tenants for their support.


What were the results?

The energy-saving performance of the roof insulation improved by 26%, according to Knauf Energy Solutions data.

The roof retrofits were included in the first wave of the buildings’ renovation in 2019 to deliver on Flemish Government targets by 2020. The full energy-saving results of the project were set be revealed in early 2022.


What lessons have been learned from Halle?

Barry Lynham, KES Managing Director, says: “At the heart of any renovation project is the issue of trust. Trust that the work will deliver the energy savings housing associations expect and trust that the retrofit will deliver the high level of comfort residents deserve. “The fact that KES can demonstrate these improvements using objective real performance data from before and after renovation — backed up by quality assurance systems — restores trust in an otherwise broken market."


Barry Lynham Managing Director, Knauf Energy Solutions

Quality drives retrofit of 164 homes in Belgian town

Belgian housing association CNUZ has appointed Knauf Energy Solutions (KES) to carry out a deep energy efficient retrofit of 164 social homes in the Gijmelberg district of Aarschot town.

The Aarschot initiative is the second biggest KES renovation project in Belgium. In June 2021, renovation work was completed on 184 social homes in the town of Halle — the biggest ever real performance deep energy efficiency renovation in social housing.

Work began on the Aarschot project in autumn 2020 and focused on a mix of small terrace houses and semi-detached properties built in the 1970s all featuring flat roofs.

As with the Halle project, the pre-renovation energy performance of the buildings was assessed by KES technology over three months. Prior to installation of monitoring equiptment, the KES tenant engagement team presented the project to residents and asked for permission to collect the necessary data.

Work began in March 2021 with a focus on tackling the issue of energy-draining cold bridges — uninsulated areas of a building where heat can leak out such as roof to wall ‘junction’ points. In addition, renovation includes the installation of flat roof insulation and Knauf Insulation cavity wall insulation as well as the upgrading of heating systems and ventilation.

Barry Lynham, KES Managing Director, says: “The primary concern of all KES projects is quality. Quality solutions and quality installation work.

“In the case of Aarschot this has meant finding innovative solutions to the issue of cold bridges which minimise disruption for tenants and avoiding changing the external appearance of homes to avoid the requirement for a permit.

“The second issue has been quality work. All our contractors and sub-contractors go through collaborative planning sessions with KES before they start.

“We appoint project managers on site to ensure quality standards, bring in specially trained teams to test the effectiveness of our products and, if necessary, appoint specialist subcontractors for specific project work.”

The mass renovation in Aarshot is scheduled to be completed by the end of 2021.

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