Object reportage: Densely built water worlds

Photo: Leipzig Zoo

Densely built water worlds

Time-optimized base sealing with Botament

Leipzig Zoo is one of the most species-rich zoos in Europe. Among other things, there is an aquarium built in the Art Nouveau style, which has been extensively modernized in the last three years. Here, penetrating moisture posed a problem for the building fabric for decades. During the repair work, Botament’s reactive waterproofing RD1 Universal proved to be an easy-to-apply waterproofing material that provides long-term moisture protection in the base area.

The structure of the more than 100-year-old zoo building in Leipzig recently showed clear signs of damage due to permanent exposure to water and moisture. The technical equipment and energy factors also no longer met today’s requirements. Therefore, a new chapter in the traditional history of the aquarium was opened and modernization was carried out.

The aquarium of the Leipzig Zoo was built in 1910 in Art Nouveau style and houses a unique diversity of species.
A new wing was added to the historic building in 1992.

The structural engineering conditions in the areas of monument, fire and flood protection, which had been adapted over the years, made the planning of the construction project more difficult. In order not to unnecessarily prolong the closure phase of the aquarium, a solution was sought that would allow the repair of the foundations in contact with the ground to be carried out safely and in a time-efficient manner. Botament’s highly flexible and crack-bridging reactive waterproofing RD1 Universal was used to reliably seal the base areas. In this context, the fast processing and setting of the waterproofing guaranteed a speedy completion of the rehabilitation measures. As early as September 2020, the company Boost from Mücheln (Saxony-Anhalt) began the exterior work. After the foundations of both parts of the building were exposed, the contractor applied the reactive waterproofing in the spring of 2021.

Easy processing

Thanks to the single-component formulation of the universal waterproofing, mixing of the material at the construction site is no longer necessary. Ready for use and applicable without primer, RD1 also impresses with its particularly short drying time. While conventional bitumen-based waterproofing requires a drying time of up to five days, Botament’s bitumen-free waterproofing is rain-ready after just six hours. Insulation and drainage boards can also be bonded after just eight hours. The product’s color change – from a garish petrol when wet to a bright turquoise – makes it easier to control the drying process. The solvent-free polymer dispersion has a long pot life, making the seal much easier to apply than conventional two-component reactive sealants, especially on warm days.

Botament's reactive waterproofing RD1 Universal enabled the plinth areas to be sealed quickly and securely - despite the partly fissured masonry.
RD1 is ready for use and can be applied by spraying - without prior priming. The color change of the bright green reactive sealant indicates the degree of drying of the applied layer.

Spraying instead of filling

Another advantage is that the reactive sealant can be applied by brush, trowel or spray. Time-efficient and particularly economical, it was applied by machine in Leipzig. For this purpose, the first step was the installation of sealing tapes. Subsequently, the substrate was pre-wetted. The particularly damaged base of the new building wing, which was opened in 1992, was treated in advance with cement plaster. Then all that was needed was to set up the spraying machines and adjust the spray pattern. Finally, highly flexible and crack-bridging, a thin layer of fiber-reinforced waterproofing ensures that the aquarium foundations are once again watertight. Due to the high frost and aging resistance of RD1, the bases and thus also the interior of the popular zoo facility are protected from damage in the long term.

In addition to the tightly timed construction schedule, the zoo’s location also had to be taken into account. This is because it is located in the immediate vicinity of the banks of the Parthe River. Here, the groundwater rises particularly high over the entire area of the zoo. With the help of the newly applied reactive waterproofing RD1, water will be reliably drained away in the future and the building fabric will be sustainably protected against moisture.

The base renovation was completed in just a few weeks in the spring of 2021. The highly flexible and crack-bridging reactive waterproofing protects the historic building stock from water penetration in the long term.