A tile covering in a car dealership has to withstand a lot: high mechanical loads in the showroom area as well as strong temperature differences due to sunlight. Additional challenges arise if the job has to be done quickly and therefore tile upon tile is laid. High-quality system products and professional procedures offer reliability to the craftsman.

At the A.M.T. Car dealership in Erlenbach, Lower Franconia, a new tile covering was to be laid on top of the existing ceramic flooring in a section of the showroom. This was already the fifth car dealership with this requirement for Schrank-Fliesen GmbH. Laying tile on tile first requires a thorough examination of the substrate. Are there different substrates existing? Is the old tile covering intact and professionally laid or does it show damage or hollow layers? It must also be checked whether there is an offset, i.e. differences in height due to screed fields, and whether joints are cracked as a result. And last but not least, installers must also clarify how movement joints can be relocated if the old and new tile coverings do not have the same format, as was the case at the A.M.T. car dealership, for example. There, new 60 x 60 centimeter tiles were to be laid on top of the 30 x 60 centimeter tiles.

Examination of the existing floor

As he had done before, Volker Schrank, the owner of the master tiling company, contacted PCI specialist adviser Peter Scharf and PCI application engineer Richard Rast for a set-up recommendation. “We had to take a close look at the existing floor. And that is exactly what PCI application technology offers with its consulting service. This is what makes working together so valuable to me. I can rely on the recommended structure and product selection. I recently convinced myself in one of the local car dealerships: the tiles are exactly as we installed them more than five years ago. Not a single defective spot. That's why I'm absolutely loyal to the system," says Volker Schrank. After the joint on-site appointment at the car dealership in Erlenbach, he received the installation recommendation with the right products and instructions on how to proceed.

Isolating the substrate

The prerequisite for reliable tile laying is always a substrate that is clean, free of grease, firm, able to bear weight and free of residues on the surface that might impair adhesion. The craftsmen primed the substrate prepared in this way with PCI Gisogrund 404, a special primer for absorbent and non-absorbent substrates such as ceramic tiles. The PCI Pecilastic E isolating membrane, which compensates for tension, substrate deformation and temperature fluctuations, was applied to the dried primer. PCI Pecilastic E absorbs the movements from the joints and displaces them - and thus has all the necessary properties for the subsequent tiling in the car dealership. Another practical feature is the simple and fast application: the isolating membrane is ready to use and is bonded directly to the substrate. The joints are covered with adhesive tape. Once the adhesive has hardened sufficiently, the craftsmen can lay the tiles on it, this was the case at the A.M.T. Autohaus after about two days.

Sufficient number of joints

The craftsmen used the same adhesive for bonding PCI Pecilastic E as for laying fully-vitrified tiles: PCI Flexmörtel S1 Flott. Although the flowable mortar replaces the buttering-floating method, they used the combined method according to DIN 18157-1 in the car dealership to improve the adhesion of the large-format tiles. This is necessary for tiles larger than 0.25 square meters. For a reliable work result the PCI application engineers recommended to plan movement joints at a maximum distance of 5 - 6 meters to allow for the thermal linear expansion of the ceramic. This was made necessary by the expected solar radiation and the relatively dark color of the tiles. The craftsmen grouted the joints with a width of about four millimeters using PCI FT Megafug. The cementitious grout is easy to apply due to its smooth consistency and, like PCI Flexmörtel S1 Flott, is emission-free according to GEV-EMICODE EC 1 PLUS. Because the tile covering grouted with PCI FT Megafug can be walked on after only two hours, the movement and connection joints could be quickly closed with PCI Silcofug E elastic and the work completed.

Proven cooperation

"Once again, the cooperation with PCI has proven to be very successful. The result is impeccable and we were able to carry out the project quickly and without any problems," says Volker Schrank looking back. "Even though I am now well familiar with the procedure and product selection for the 'tile on tile' requirement, I will contact Peter Scharf and Richard Rast also for the next project. In detail, every old floor is different. The expert assessment and installation recommendation give me reliability."