Finished Up

When renovating the façade of a residential and commercial building in Berlin, the old plaster should be preserved. Jens Brühl, Dr. Günter Glock, Baumit The client's specification was to repair an exterior facade on a five-story residential and commercial building in Berlin at Lietzenburgerstrasse 99. For ecological and economic reasons, the aim was to preserve the old plaster as far as possible. Damage patterns The previous damage to the old facade was shown in the form of cracks, plaster breakouts, destruction of the stucco cornices and partial flaking of paint. Especially in the area of the balcony parapets or soffits, the old plaster was severely damaged by the effects of massive moisture. The stucco cornices consisted largely of gypsum mortars, which were rebuilt with gypsum during the reprofiling. For this purpose, great care was taken to separate gypsum-containing materials from cement-bound mortars. The basis of the renovation work carried out was the BFS leaflets 19, 19.1 and 20.1 "Cracks in external plasters - coating and reinforcement", "Cracks in unplastered and plastered masonry, in plasterboard and similar materials on substructures - causes and processing options", "Assessment of the substrate for Plastering - Measures and elimination of damage”as well as the WTA leaflet 2-04-08 / D“Assessment and repair of cracked plasters on facades.”Facade renovation The old facade was cleaned with a steam jet and freed from all loose and worn paint layers and plaster detachments. In order to check the load-bearing capacity of the old substrate for the subsequent mortar revisions,So-called tear tests were carried out on selected facade areas. For this purpose, an area of approximately one square meter is filled with a plastic-coated facade spatula on the cleaned and dried old plaster in a thickness of approximately 5 millimeters. An alkali-resistant glass fiber reinforcement fabric is embedded in the fresh filler layer in such a way that an approx. 15 cm wide strip of fabric protrudes from the upper edge area. After a hardening time of approximately one week, the glass fiber fabric is pulled down strongly on the upper strip. The test for tear-off strength is passed if the reinforcement fabric is torn out of the spatula without any parts of the old plaster or the old paint adhering to the underside of the filler layer. A plaster filler was used as the material. In the present case, the old plaster proved to be sufficiently load-bearing - there was no obstacle to a technical overhaul. Larger outbreaks or cavities were built up with mineral light plaster before the surface was renovated. Only in the areas where the masonry made it necessary was a pre-spray mortar of strength class CS IV in accordance with the cleaning standard DIN EN 998-1 used for adhesion. Pronounced, reworkable individual cracks (see WTA leaflet 2-04-08 / D "Assessment and repair of cracked plasters on facades", procedures E 2 and F 5) were expanded and filled with a facade spatula. This increases the effective expansion length of the crack and improves the crack bridging ability of the facade filler. After the corresponding standing times of one day per millimeter of application thickness of the plastering mortar or facade filler used, the entire surface of the facade was filled with a layer thickness of about three millimeters and the fine reinforcing fabric was embedded (alkali-resistant). In the edge area, the fabric sheets were overlapped at least ten centimeters wide. After a standing time of another day per millimeter of plaster thickness, the top plaster was applied with a fine grain structure of 0.7 millimeters as desired. The top coat is characterized by a coordinated strength development based on lime with highly hydraulic additives and an excellent processing ability. The product is preferably used in the area of monument conservation. The color of the entire outer facade was made with a crack-filling color in the patterned historical color. Preserved, undamaged old plaster areas could be renovated directly with this color system. Particular attention was paid to the repair of the stucco cornices with materials containing gypsum. The damage pattern showed a variety of cracks, flaking or partial loss of material. The new application was made using the wall pulling method with partial substructures made of stainless steel fasteners. Outlook The renovation work was successfully completed after approximately 10 months of reconstruction work. The building shines in new splendor and could be handed over to the client for use. Preserved, undamaged old plaster areas could be renovated directly with this color system. Particular attention was paid to the repair of the stucco cornices with materials containing gypsum. The damage pattern showed a variety of cracks, flaking or partial loss of material. The new application was made using the wall pulling method with partial substructures made of stainless steel fasteners. Outlook The renovation work was successfully completed after approximately 10 months of reconstruction work. The building shines in new splendor and could be handed over to the client for use. Preserved, undamaged old plaster areas could be renovated directly with this color system. Particular attention was paid to the repair of the stucco cornices with materials containing gypsum. The damage pattern showed a variety of cracks, flaking or partial loss of material. The new application was made using the wall pulling method with partial substructures made of stainless steel fasteners. Outlook The renovation work was successfully completed after approximately 10 months of reconstruction work. The building shines in new splendor and could be handed over to the client for use. The damage pattern showed a variety of cracks, flaking or partial loss of material. The new application was made using the wall pulling method with partial substructures made of stainless steel fasteners. Outlook The renovation work was successfully completed after approximately 10 months of reconstruction work. The building shines in new splendor and could be handed over to the client for use. The damage pattern showed a variety of cracks, flaking or partial loss of material. The new application was made using the wall pulling method with partial substructures made of stainless steel fasteners. Outlook The renovation work was successfully completed after approximately 10 months of reconstruction work. The building shines in new splendor and could be handed over to the client for use.

compact

The outer facade of the residential and commercial building in Berlin's Lietzenburgerstrasse 99 was renovated from an ecological and economic point of view. Products BaumitBayosan: plaster filler multiContact MC 55 W light plaster LL 66 Plus priming mortar VS 60 top plaster Kalkin RK 70 N BaumitBayosan Reckenberg 12 87541 Hindelang Tel.: (08324) 921-0 / Fax: -470 www.baumitbayosan.com