Architect: Bureau Bouwtechniek
Client: Klimaatwijken Mechelen
Status: Executed
The apartment block at Koningin Astridlaan 159–161 in Mechelen dates from 1978–1979 and consists of two sections, each with eight storeys, comprising a total of 59 flats and two commercial premises on the ground floor. The building forms part of the Mechelse Vesten and was assessed as part of the Mechelen Climate Districts project.
The apartment block at 159–161 Koningin Astridlaan exhibited various defects in the building envelope. In an initial phase, Bureau Bouwtechniek assessed the condition of the building and mapped out the possible renovation scenarios.
The investigation revealed, amongst other things, that the natural stone cladding was damaged in several places. Some of the panels had buckled due to a failure in the bond with the underlying mortar layer. The anchoring of the existing panels also proved to be a key area of concern. In addition, there was localised concrete damage on the terraces and behind the cladding.
Following the feasibility study, Bureau Bouwtechniek was commissioned to further develop the renovation and maintenance works on the front façade. A targeted renovation approach was chosen, building on the existing façade as much as possible.
The natural stone panels are being inspected one by one. Panels that are too badly damaged or warped are being removed and replaced with new natural stone of a similar appearance. The retained panels are being fitted with additional mechanical renovation anchors secured to the underlying stable structure. Damage and areas around the new anchors are being repaired locally.
The existing cement-bound pointing is also removed and replaced with flexible joints. Following the repairs, the natural stone is thoroughly cleaned. This not only addresses the technical safety of the façade but also minimises the visual impact of the works as much as possible
From 362 to 127 kWh/m² per year
For the most critical flat, we calculated the impact of successive energy-efficiency measures on the building envelope. By treating the front façade, roof, rear façade and side façades as components of a single renovation strategy, the calculated primary energy consumption falls from approximately 362 to 127 kWh/m² per year.
More than just natural stone restoration
The renovation is not limited to the façade panels. Existing concrete damage to the underside of the terraces and behind the façade cladding will also be repaired. The terrace ceilings will additionally be given a protective finish.
On the terraces on the front façade, the drainage system will also be addressed. The specifications provide for new connections for the waterproofing at the drainage points.
Our remit
Bureau Bouwtechniek initially assisted the Owners’ Association in assessing the existing condition and evaluating possible renovation scenarios. Based on that study, the chosen approach was further developed technically into a feasible renovation project.
For the façade renovation, we are responsible for the technical design and project supervision. The approach combines additional investigations during the works with the repair, replacement and re-anchoring of the natural stone. The final scope of certain interventions will be determined on the basis of the condition observed during the works.
A feasibility study as a starting point for renovation
A feasibility study need not end with a report. On Koningin Astridlaan, the investigation of the existing building envelope formed the basis for making well-founded decisions about the further approach. Based on the damage identified and the scenarios examined, a targeted renovation plan could be drawn up, involving intervention where technically necessary whilst preserving as much of the existing façade as possible.
