Table of contents:
Video: Cafeteria, Hagerhof Castle
It echoes in the historic vaulted cellar. Like the boarding school at Schloss Hagerhof in Bad Honnef, it is used as a cafeteria.
In addition to modern, atmospheric lighting, acoustic measures were therefore essential. High noise pollution is not uncommon in a cafeteria. Noise is reflected from the reverberant surfaces and thereby amplified. In the vaulted cellar of Schloss Hagerhof, these are the brick walls and ceilings as well as the tiled floor. The sound waves are reflected as reverberation, making entertainment more difficult. Property planner Raffauf asked the construction company to determine the reverberation times and to work out solutions for the improvement. Based on these calculations, he developed an overall concept.
First of all, the plaster layers from decades had to be knocked off the massive walls, which were over one meter thick. Parts of the exposed masonry made from local Grauwacke were re-grouted and remained unplastered as decorative walls. This restricted the range of wall surfaces that could be used for acoustic measures, because only the wall areas above mechanical influences and below the vaulted ceiling could be used. "We didn't want to apply acoustic spray plaster to the cross vault, the ridge should be preserved in order not to change the architectural appearance of this historic element," explains Stefan Raffauf.
Multi-layer renovation plaster
With the acoustic system on the walls and ceiling sails with integrated lighting, the reverberation time was reduced. The acoustic system consists of a light, highly porous mineral acoustic plaster base plate that is coated with an open-pore mineral plaster. Only such a diffusion-open, mineral acoustic system could be considered on the damp walls. The panels were glued to the wall at a height of approximately 1.5 to two meters below the vaulted ceiling. Renovation plaster came to the walls below the acoustic surfaces. Expert reports had shown that extensive drainage of the masonry would only be possible as an internal or external seal with considerable time and financial expenditure.
Those responsible decided to use the plastered surface as a storage level for the wall moisture - with plaster application thicknesses of up to ten centimeters. In the base area there were even significantly more. The multi-layer renovation plaster system was specially developed for the renovation of damp walls. It consists of trass pre-plaster as a bonding bridge on masonry, followed by trass-pore base plaster, a base and salt storage plaster as leveling plaster for heavily uneven masonry, and finally trass renovation plaster for realizing dry, flat surfaces. “When applying the renovation plaster, many large air-filled pores form. These air spaces interrupt the capillary line of the rising moisture and the mineral salts dissolved in it from the ground and the bricks. The dissolved salts are deposited in the capillaries and crystallize without the plaster flaking off and there being efflorescence on the surface,”explains planner and property consultant Bernd Hauröder. In this way, a efflorescence-free and dry surface can be achieved on damp masonry if the surrounding climate allows it to dry out. In the canteen at Schloss Hagerhof, the air conditioning technology ensures a balanced indoor climate and regulates the air exchange rate. In the canteen at Schloss Hagerhof, the air conditioning technology ensures a balanced indoor climate and regulates the air exchange rate. In the canteen at Schloss Hagerhof, the air conditioning technology ensures a balanced indoor climate and regulates the air exchange rate.
Acoustics and lighting
The painters applied renovation putty as the last layer. This made it possible to achieve a finely structured surface similar to that on the surfaces equipped with the acoustic plaster system. The brick vault was plastered and coated with sol-silicate paint. Stefan Raffauf designed special profiles with indirect lighting for the transition from renovation plaster to acoustic plaster. These take up the design language of the cross vaults and, thanks to the discreet indirect LED technology, provide pleasant lighting for the hall.
The refectory in the Schlosskeller Hagerhof with its historical room layout with vaults, columns, arches and straight walls after the renovation.
CapaCoustic Fine, CapaCoustic Melapor ceiling sail, Histolith Trass renovation plaster, Histolith renovation
filler, Histolith spatial quartz, Capapor special profiles
Photos: Willi Fuchs Photography