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St. John´s Church, Schwaebisch Gmuend

General Information

The Johanniskirche (St. John’s) in Schwäbish Gmünd is a typical late Romanesque column basilica built from around 1220 to 1250 on the foundations of an earlier 12th century church. The structure is richly adorned with sculptural ornamentation from the animal and fable world as well as plant embellishments. The Gothic and Baroque periods brought destructive changes, but during the 19th century a “Re-Romanization” restored the church to its original state. The choir is a reconstruction from the 19th century. During this restoration, Karl Dehner from Rottenburg painted the walls of the nave as they appear today. Currently, the church functions as a museum but is occasionally used to house special public events. Sculptural fragments from the Johanniskirche as well as Heilig Kreuz Münster (Holy Cross Minster Cathedral) nearby are contained in the aisles of the Johanniskirche. The church’s primary construction material is local sandstone, which is quite fragile; however, the roof is a wood-framed structure with tile shingles. The ceiling of the nave is constructed with timber planks, but it should be noted that neither the ceiling nor the roof are water tight or thermally insulated. In addition, many gaps in the tiles and planks create a state of constant air flow from the exterior to the interior of the church and vice versa. As a result, water condensation is sometimes seen running down the walls of the clerestory, damaging the paintings, and puddles form on the floor of the church.

Monitoring objectives

Since late 2009, climate data has been collected at various locations on the interior and exterior of the Johanniskirche. The goal is to use this data to monitor moisture in the structure so as to mitigate problems and prevent future damage to both the structure and interior decoration due to humidity and the resulting condensation.



The monitoring system used to measure climate data is provided by Smartmote. Implementation and evaluation of the measurements are conducted by Smartmote in conjunction with the Materials Testing Institute at the University of Stuttgart. Instantaneous data collected from the church is available in both tabular and graphic forms on the current data page. There is also the option to plot a comparison of any two motes for a user-defined time span.

Currently, research is underway to create a model that incorporates the collected climate data to detect the flow of moisture through the walls and determine a critical point at which action must be taken to prevent condensation damage. WUFI, a computer program specializing in calculating the coupled heat and moisture transfer in building components based on research regarding vapor diffusion and liquid transport in building materials, is the program used to model the climate at the Johanniskirche. Using WUFI, a material cross section is specified by using materials from the material database or by creating a user-defined material. In the case of the Johanniskirche, the cross section will be comprised of three layers: native sandstone on interior and exterior surfaces and rubble infill in between. Other critical inputs include component type (i.e., exterior wall, roof, etc.), orientation (i.e., north, south, east, etc.) and angle (i.e., 0° for horizontal surfaces, 90° for vertical surfaces, and varying angles according to roof pitch). The temperature and humidity data collected by the monitoring system is imported as interior and exterior conditions, respective to the sensor location. WUFI provides the option to display a time step video during analysis to help identify times of critical climate. The WUFI analysis will be compared with climate data to identify critical conditions that contribute to condensation issues. Once validated, it will be made available in the current data section. This information will help create a plan of action with regards to methods for controlling the interior climate of the church (i.e., opening/closing windows and doors, installing a climate control system, etc.)

Results

Details of the monitoring campaign including actual monitoring data could be found at www.shm.uni-stuttgart.de (external link)

WP6: Project Report






Created by: admin. Last Modification: Tuesday 14 of February, 2012 13:24:02 CET by admin.