REFURBISHMENT OF AN ARCHITECTURAL MONUMENT

THE “BADI” OUTDOOR POOL IN AARBURG

Built in 1931, the Aarburg outdoor swimming pool is considered the oldest example of this type of building in the canton of Aargau. Largely preserved in its original state, it is an important architectural monument that bears witness to the growing enthusiasm for sport and nature in the early 20th century. The pool facility has been a cantonal listed building since February 2022. The refurbishment carried out in 2021/22 has succeeded in both largely respecting the historic building and modernising the infrastructure and equipment. New findings about the original colour scheme have made it possible to restore the unique character of the architectural monument.

The basic principle for the building work on the technical modernisation was to preserve or, where possible, restore the original appearance of the outdoor pool. The main interventions included the restoration of the original building fabric in accordance with monument preservation guidelines, the evidence-based reconstruction of the elements no longer preserved, replacement of the pool basin no longer amenable to preservation, construction of a new plant building, reorganisation of the sanitary facilities within the existing building fabric, relocation of the paddling pool and the restaurant to the south-east of the site, and improvements in the design of the surroundings.

The new concrete basin, which is slightly lower in relation to its surrounds and has an internal overflow channel, creates a spatial impression physically and visually similar to the original appearance. As a result of the demolition of the old plant building from the 1950s, the view of the river Aare has been restored. Combining the protected building fabric with contemporary equipment, the new plant building at the Badstrasse entrance forms a visual screen between the sunbathing lawn and the car park. The surroundings at the southern end of the pool have been upgraded by omitting diving boards and by introducing wooden seating steps that invite users to linger.

Colour scheme of the construction period

One of the most striking changes is the restoration of the original colour scheme of the Aarburg pool facility. In the course of refurbishment, it was possible to identify the original colours of the various parts of the building thanks to paint analysis by a restorer. A palette of bright, bold colours emerged, which is absolutely typical of the construction period and can be found in buildings erected at the same time, including modernist outdoor pools.

In Aarburg, the colour scheme features subtle gradations. While on the outside it appears more subdued and restrained in relation to the surrounding buildings, on the inside the bright colours of the cubicle doors, now again in wood, light up all the more.

Strict guidelines for monument preservation

The goal of listing the historic box-like pool building as a national monument could only be achieved by constructing the pool in fair-faced concrete. Pools made entirely of fair-faced concrete are a rarity nowadays; this requirement presented the design team with some challenges. Likewise, the pool was to have a low-lying overflow channel, which required meticulous design of the end of the pool without compromising the pool’s water-tightness.

After developing various alternatives that led to nothing, a channel design was finally devised that would give the pool the required water-tightness while preserving the desired historical appearance. The solution consists of a combination of a channel head concreted on site and connected to the pool surrounds and a cemented-in overflow block.

State-of-the-art pool water treatment

All the plant for pool water treatment, including the supply and return pipes, was replaced and brought into line with current standards. A new water treatment system with a pressurised precoat filter was adopted. To ensure optimal pool hydraulics, a vertical floor inlet was chosen, which is almost concealed by the swimming lane markings on the floor of the pool. The entire system has been housed in a new and floodproof plant building.

Children’s paddling pool as a new attraction

To upgrade the facility, a new children’s paddling pool with a sun shade system and soft EPDM pool surround has been added. The new paddling pool has been moved from the historic part of the facility to the edge of the site. Together with a small playground and the nearby catering area, this part of the complex forms an oasis for young and old.

Unique bathing pleasure in a historic setting

With the latest refurbishment, today’s requirements of an outdoor swimming pool in terms of equipment, hygiene, comfort and accessibility have been successfully reconciled with treatment of the building in a manner in keeping with its listed status. The historic building fabric has been retained as far as possible and preserved for future generations. By removing various alterations from the 1950s as well as the rediscovered colour scheme, the essential architectural qualities have been restored to Aarburg’s river and sunbathing pool facility. With its combination of neoclassical formal language and modern colouration, the Aarburg pool is a unique architectural and cultural testament to a period of architectural and social transition.