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Overnight service in the Ruhr-Park

The "Blue Wave" in Germany´s largest shopping centre has been renovated using products from Ufloor Systems

  • Building Type: Commercial Construction
  • Pad: Natural Stone
  • Brand: Codex
  • City: 44700
  • Country: International

When the huge Bochum shopping mall of the “Ruhr-Park” is filled again every morning with 45 to 50 thousand shoppers, they can hardly realise that over the previous night, the floor beneath their feet has been replaced – another section every night. Like the famous Cologne pixies, the natural stone-layers of the Bochum natural design firm of “Natur und Stein Dembler” renovated the stone floors of the so-called “Blue wave” and some adjoining natural stone surfaces, working only at night over a period of several weeks. The work was carried out using the Uzin system of flooring materials, under the expert supervision of Siegfried Heuer, a legend in the trade.

With a sales area of almost 126,000 m2, the Ruhr-Park is Germany’s largest shopping centre. Started in 1964, the shopping centre now covers an area equal to 60 football pitches (252,000 m2), and was last extended in 2001. This occasion also saw the opening in October 2001 of the “via bartolo” – a gastronomy area with Mediterranean flair, provided amongst other things by real olive trees and two striking fountains. Its trademark is the characteristic blue wave from the via bartolo logo, which winds its way along the floor through the total of thirteen differently styles restaurants and on into the adjoining walkway.

Labrador Blue Pearl - elegant remake of the blue wave

In 2001, a 13 millimetre thick, deep blue artificial stone with sprinkled through with mirror-glass was first selected for the blue wave design. This subsequently proved not to be up to the stresses of a shopping centre, and now had to be replaced. Needing on the one hand to create an adequately hard-wearing floor, while on the other not wanting to give up the blue colour completely, the planners were left with very little room to manoeuvre.

Frank Dembler, who had already built the fountains in the Ruhr-Park, finally decided on a Norwegian Blue Pearl larvikite with a flamed and brushed surface. Originally a landscape gardener by trade, Dembler’s favourite hobbyhorse for the last 25 years has been natural stone, as he explains. The stone used here at his suggestion was also given a deeper colour in addition to the impregnation, in order to compensate for the loss of colour caused by the non-slip treatment (flaming and brushing).

The blue-grey Blue Pearl larvikite is also known as Labrador Blue Pearl. This is because the feldspars (mixed crystals of alkali feldspar and plagioclase feldspar, so-called ternary feldspars) in the stone contain fine lamellae, which give off a striking blue shimmer. This is referred to as “labradorising”, and subsequently gave this decorative stone its trade name: “Labrador”.

Nor did the Center Management of the Ruhr-Park have to miss out on the light reflections. With this natural stone, the reflections are provided by the feldspar crystals, which glitter in the light in all shades from blue to silver. The via bartolo therefore still has its blue wave – although one which looks even more refined and elegant.

Visual and technical challenge

From mid-October to mid-November 2006 in the first section, and then again from 9th January to 23rd February, the Dembler natural stone-layers provided their overnight service, which in addition to the blue wave also included replacement work in the adjoining Bianco Sardo area. Dembler was proud to have found, after such a long search, a material which differs only slightly from the original stone, but can still be distinguished from the original Bianco Sardo with the naked eye, due to the slightly varying surface finish.

The challenge of finding a stone which was suitable in terms of both appearance and strength was compounded in this project by the technical difficulty of producing perfectly sealed joints – firstly because of the wet cleaning of the surface every day, and secondly because of the required damp barriers in the area of the fountains. And the floor-layers finally also found pockets of unstable screed, which necessitated complete renewal of the substrate.

In view of all these circumstances, Siegfried Heuer recommended on relying of the quality of the products and the product adhesion of Uzin. “We therefore used only products from Uzin for the whole job”, Frank Dembler was happy to reflect later, because “it was demonstrated that all the materials kept the promises made by Uzin.” Dembler also expressly praised the expert recommendations of the Codex Area Managers Peter Krause and Stefan Marx. His decision in favour of products from UFloor Systems will be made even easier in future due to the fact that the company has opened its own training centre nearby in Oberhausen. Seminar programmes for customer training and further events are already available.

An institution in the trade: Siegfried Heuer

The fact that Dembler and his men had Siegfried Heuer on hand with advice and support for this project naturally contributed to the confidence of the craftsmen. The specialist, assessor and acknowledged flooring expert – many current luminaries in the trade trained under him – has continually been looking after this property for four years.

Under contract from the Center Management, he is responsible for the quality assurance of the renovation measures. This means amongst other things: identifying and marking areas of damage, definition of floor areas to be relaid, assistance in the compilation of tenders and contract awards, production of the work schedules and also: production of system-oriented construction recommendations. Since Heuer is completely familiar with the whole Uzin product range, including the laying materials for natural stones being marketed since recently under the new brand name “Codex”, he was happy to recommend their use.

Laying materials & method

Night after night, the natural stone-layers tackled a new section of floor. First they removed the old covering and milled the screed surface. The reason: The thicker build-up (20 mm of natural stone instead of 13 mm of artificial stone) and the different type of build-up. Where the screed was found to be unstable, Siegfried Heuer had the substrate completely replaced. Dembler’s craftsmen removed the screed and filled in these areas with the pre-mixed fast screed mortar Uzin NC 192. The advantage of this product: very early readiness for laying, both indoors and outdoors.

They then sealed the ground screed with the epoxy resin primer Uzin PE 460. “In the corresponding quantity and with double application, PE 460 acts as a capillary-breaking layer, and therefore as an effective sealant”, explains Dembler. Heuer and Dembler both placed great value on the damp barrier in the Bochum Ruhr-Park, particularly because of the water to be expected from the fountains and from the wet-cleaning machines.

The natural stone panels were accurately cut by the craftsmen to the exact wave shape, and then laid in a thin-bed mortar of codex Stone Flex using the buttering & floating method (to DIN 18156, Part 1). The Uzin thin-bed mortar is low-slump, quick-setting, white, and with a high plastic content. They finally created a smooth, finely closed joint surface with the aid of codex Flexfuge Brillant Stone.