Löhr Center, Koblenz
Chemistry to build on
Project Shopping mall refurbishment under operating conditions All works to public spaces performed overnight Walkability of areas required by next morning Use of Sopro extra-rapid-set system solutions to install coverings on top of structural concrete
Signboard Applicator
Baukeramik Wedekind GmbH, Mehring
Client
ECE Projektmanagement GmbH & Co. KG, Hamburg
General contractor
Ed. Züblin AG, Central Germany office, Frankfurt/Main
Contract volume
Approx. 6,000 m²
Completion
March 2017
Products Sopro Rapidur® B3 rapid-set screed binder (order no. 768) Sopro Rapidur® B5 rapid-set screed binder (order no. 767) Sopro's No.1 rapid-set flexible tile adhesive (order no. 404) Sopro GD 749 primer Sopro VF 419 VarioFlex® Silver large-format flexible tile adhesive Sopro FL flexible tile grout
Löhr Center, Koblenz I www.sopro.com
www.sopro.com
Finished scheme
Lรถhr Center, Koblenz I www.sopro.com
Finished scheme
Lรถhr Center, Koblenz I www.sopro.com
Construction phase
Lรถhr Center, Koblenz I www.sopro.com
Löhr Center, Koblenz
Shopping mall successfully refurbished under operating conditions
Fast, trouble-free site operations guaranteed through use of special products supplied by Sopro Bauchemie GmbH The Löhr Center in Koblenz is one of the biggest inner-city shopping centres in the German Federal State of Rhineland-Palatinate. For refurbishment of the mall floors under operating conditions, the design and applicator teams opted exclusively for the use of Sopro Bauchemie GmbH’s rapid-set systems. The last two years have seen Koblenz's ageing Löhr Center, which opened back in 1984, undergo comprehensive refurbishment and modernization. The project, commissioned by the operator, Hamburg-based ECE Projektmanagement GmbH & Co. KG, included a generously sized entry portal at the Rosenbrunnen entrance together with an outdoor catering facility on the shopping centre forecourt. Apart from adding 31 new shops, the remodelling and modernization scheme included a facelift to the Löhr Center’s internal street. In particular, the public mall spaces were restyled and fitted with a modern tile covering to meet the demands of a contemporary retail facility.
Night-time working specified as requirement The brief for the Löhr Center refurbishment project called for the installation of new floor tiling to create a warm and inviting (shopping) atmosphere. Renewal of the floor covering had been necessitated by severe damage to parts of the existing ageing stone finish. The requirement for the mall flooring to be renovated within as short a period as possible and under operating conditions posed a string of logistical problems. To prevent unreasonable disruption to the operation of the Center and its numerous retail outlets, the total area of around 6,000 m² was refurbished exclusively during the night in predetermined sections of approx. 150 m². Not only did this require the speeding up of works on site, but also a meticulous and elaborate planning of the tilelaying operations. The tiling works were performed by Baukeramik Wedekind GmbH. Based in the town of Mehring in the Mosel valley, the specialist contractor with a 50-year track record describes itself as a company that offers "masterful craftsmanship with innovative drive", always with the aim of "creating long-term value".
The first stage of the works entailed stripping back the existing natural stone finish to the structural concrete and shot-blasting the exposed substrate. In the following night shift, a new bonded screed was then laid on the prepared surfaces. To speed up the progress of works in line with the brief, the screeding works were performed using two rapidset products from Sopro Bauchemie GmbH’s trade range: Sopro Rapidur® B3 and Sopro Rapidur® B5 rapid-set screed binders. Both of these state-ofthe-art products offer designers and applicators a reliable solution for tightly scheduled projects. The choice between the two was dictated by the specific timing requirements.
Sopro rapid-set screeds as problem-solver Sopro Rapidur® B3 was specified wherever only a single night shift was available. This special, polymer-modified, ternary binder for the particularly economical production of highstrength, rapid-set cement screeds to DIN 18560, offering early mechanical strength and allowing early flooring installation, was purpose-developed for fast-track and tightly scheduled screed laying. It is site-mixed with suitably graded (e.g. 0 – 8 mm) gravel sand for screeds to DIN EN 12620 and is pumpable in the mixing ratio 1 : 4. Due to its lowshrinkage, dimensionally stable curing properties, any risk of significant changes in shape through convex or concave deformation (curling) is virtually eliminated. In particular, the material's high crystalline water binding capacity helps to make the covering walkable after only 3 – 4 hours and ready for tiling after only 24 – 48 hours. This made it possible to commence the final tile-laying operations in the Löhr Center on the following night. Sopro Rapidur® B5, likewise a special rapid-set screed binder that is mixed on site with aggregate, was specified in cases where the time constraints were slightly less stringent and walkability was not required on the very next day. Thanks to its special formulation, Sopro Rapidur® B5 exhibits rapid hydraulic setting properties that allow any type of flooring works to be performed after only five days' drying time. Like Rapidur® B3, it is therefore ideal for fast-track and tightly scheduled screed laying. For both products, the slightly dampened substrate was pretreated with a bonding layer of Sopro’s No.1 rapid-set flexible adhesive prior to wet-on-wet application of the screed mortar.
During the works, members of the Sopro Project Consulting and Technical Service teams were present on site to instruct operatives in the use of equipment and provide the contractor with advice and support throughout the production phase.
Fast, trouble-free installation of new fully vitrified stoneware covering Upon completion of the screeds, these were first treated with Sopro GD 749, a rapid-drying, highly concentrated, solvent-free synthetic resin primer for high- and variable-suction substrates, and particularly suitable for subsequent application of mineral adhesives, surface fillers and waterproof membranes. The new fully vitrified stoneware coverings, with units up to 40 x 80 cm in size, were installed using a further innovative product from Sopro Bauchemie GmbH’s fast-track system: Sopro VF 419 VarioFlex® Silver, a latest-generation, cementitious flexible tile adhesive. Sopro VF 419 excels by its high crystalline water binding capacity and accordingly high early strength and extra-rapid set. These properties and its reliable drying, even below large-format units, makes the silver-grey, S1-grade floating-bed adhesive (C2 EF S1 to DIN EN 12004) the ideal product for trouble-free installation of the large-format fully vitrified stoneware finishes currently in vogue among clients and designers. The fact that the freshly laid coverings are walkable and groutable after only around 3 hours makes Sopro VF 419 ideal for tightly scheduled schemes such as the Löhr Center refurbishment. Particularly important for the applicator – despite the product's rapidsetting properties – is its long open time, which offers ample time for placing and adjusting the tiles. Applicators also benefit from the adhesive's exceptionally smooth, creamy consistency. The joints in the coverings were finished with Sopro FL, a flexible, frost-resistant, rapid-set, trassbearing, cementitious tile grout for 2 – 20 mm joint widths. It excels by its rapid initial set, is ideal for low-suction tiles and is very easy to wash off. This easy removability helps to minimize the consumption rate. As required for the Löhr Center, Sopro FL also allows early use of the grouted covering. The new floor areas were thus opened to shoppers as early as the next morning.
Löhr Center, Koblenz I www.sopro.com