Kaifu-Bad, the oldest swimming pool complex in Hamburg, Germany, is a protected monument built in 1895. It was closed for many years because the roof was in danger of collapsing.
As part of a renovation project completed in 2015, one of the pools was converted into a saltwater bath. “The saltwater has a salt content of 6 percent, which is good for humans but bad for steel,” reports Manfred Voss of MRLV Architekten, Hamburg. “The salt will consequently cause an enormous exposure to corrosion. We knew from the beginning that a standard solution wasn’t an option.”
The architect collaborated with Stefan Heidrich, the structural engineer from WTM Engineers, Hamburg. Laminated veneer lumber, or LVL, was chosen as the primary material because wood was the only way to handle the changes in temperature, as well as the corrosive effects of the high humidity, saltwater and chlorinated water.
LVL products were used in various applications from beams to panels. LVL proved to be a very strong and dimensionally stable solution that carries even large loads. For example, despite the 14-meter-long span, the main trusses could be manufactured in a thickness of only 134 millimeters. In addition, LVL panels allowed an arched cut of the bottom of the trusses, which preserved the historical barrel-shaped vault roof. The 69-millimeter-thick panels used for the roof shell also stiffened the roof structures and stabilized the original brick walls against wind loads.
Because of the LVL elements, the project succeeded economically; all the wooden parts were industrially manufactured and were ready to install onsite, which meant significant savings in construction time. The savings from the faster installation covered the extra costs of the challenging structure and moisture-proofing.
Materials: Kerto-Q LVL from MetsaWood, www.metsawood.com
PHOTOS: MetsaWood