The Leonardo, Legacy Group’s impressive mixed-use development located just 100 metres from the Johannesburg Stock Exchange, has officially opened. Rumoured to have cost around R3 Billion, there are no compromises on the construction design and state-of-the-art finishes of this prestigious property, which towers 234 metres above the Sandton skyline. TAL successfully fulfilled specific tiling and waterproofing requirements within various areas of this multi-faceted project, a total surface area of 40 000m2.
The challenge of tiling an extremely tall building arises when specifying a flexible installation to allow for the movement of the building. Additionally, in the case of The Leonardo, was the use of a selection of trend-forward large format tiles, as is to be expected at such a prestigious address. The TAL team rose to these challenges by devising a comprehensive solution and ensuring a multi-level system was in place at the outset.
TAL Technical Representative, Eugene Pelzer, was responsible for advising on the tiling specifications and steps necessary for this project, whilst TAL’s Technical Sales Specialist, Tendai Muzondida was onsite to advise on the waterproofing aspect of this project. They explain that the first step in their multi-level system was surface preparation, including priming and floor levelling. As the tiles are large format, a levelled surface is a prerequisite to help reduce lipping of the tiles. Additionally, all areas subject to moisture were properly waterproofed before tiling. Installation of the tiles required a quick-setting adhesive which was modified to accommodate movement, as well as moisture in wet areas, together with careful attention to movement joints within the installation. A flexible grout solution is the final level of the system.
While initial construction began in 2016, TAL supplied fit for purpose products for the tiling phase from early 2018. To date, wherever there is a tile in place, TAL products have levelled and primed the surface as well as secured its position in this massive building. The tile selection included an assortment of high quality tiles with varying finishes and sizes for the different spaces within The Leonardo. These included large format tiles of 600x600mm, 900x900mm and 600x1200mm as well as cut porcelain tiles of 100x100mm and fusion type glass mosaics.
“Surface preparation was key in this project” says Pelzer. As the walls of The Leonardo are constructed of porous light weight AAC (Autoclaved Aerated Concrete) bricks, these needed to be thoroughly wiped down to remove dust and loose particles which could impair adhesion. These AAC Bricks and the wood-floated rendered walls within the building were primed with TAL Floor Primer before application of the TAL Superflex waterproofing compound. Dry wall partitioning was primed with a TAL Keycoat slurry prior to tiling, or primed with TAL Floor Primer prior to application of the waterproofing, TAL Superflex. A primer slurry was applied to power-floated surfaces prior to tiling and/ or waterproofing whilst TAL SF Primer was applied prior to the levelling compound being installed.
Variances in floor levels frequently occur in multi-level structures such as The Leonardo. These were rectified prior to tiling to prevent excessive adhesive bed thicknesses and reduce potential lipping of the large format tiles, using TAL SlabPatch Flowable. “Due to the nature of power floated post-tensioned coffer slabs, the levelling compound was wet-bonded to the concrete using TAL SF Primer”, explains Muzondida.
To ensure a waterproofing installation fully compatible with cementitious tile adhesives, TAL specified TAL Superflex I. “This system, when cured, also provides a flexible waterproofing layer that can accommodate normal structural movement in the background”, explains Muzondida. This system was applied to all bathroom floors and shower enclosures in the Apartments, to the ‘wet’ areas in the Gym/Spa, Hot & Cold Pools, Steam Room, Shower, Bathroom and WC floors, and to screeded balconies and terraces prior to tiling. “A total of approximately 12 200m² was waterproofed with TAL Superflex I,” waterproofing specialist Muzondida continues.
TAL-Accredited Waterproofing Sub-contractor, Ngobeni & TDS, confirmed that, “Subsequent water tests performed on these waterproofed structures have proved the efficacy of the system.”
“The tile adhesives were selected to accommodate the requirements of different areas within the building,” confirms tiling specialist, Pelzer. Large format porcelain tiles were installed In the Apartments, on the apartment balconies and in the lift lobbies of the Apartment Levels, as well as on the Terraces and Viewing Deck, all using quick-setting TAL Goldstar 12. This adhesive has a longer pot life and open time, which was ideal when tiling in the hot summer months. The tiled finishes to the Upper Level Spa/Gym included fusion-type glass mosaics which were installed using TAL Fine Epoxy Mortar & Grout, designed for applications where imperviousness, chemical resistance and good hygienic conditions are important. A highly modified adhesive system of TAL Goldflex + TAL Bond was specified for fixing the porcelain and silestone tiles in the steam rooms due to the extreme operating conditions associated with these installations. Porcelain tiles were installed to the rest of the spa areas using TAL Goldstar 6 + TAL Bond.
TAL Wall & Floor Grout, was modified with TAL Bond as a total water replacement in the mix and then applied to the joints of the tiled surfaces throughout the apartment levels. Whilst TAL Water-Based Epoxy Grout was specified for grouting between the porcelain tiles and silestone slabs in the ‘wet’ areas of the Upper Level Spa, pool splashbacks, steam room and shower, to provide an impervious and hygienic finish.
As post-tensioned concrete suspended slabs are prone to increased movement, it is essential that these are catered for in the tiling installations to limit cracking and lifting of tiles. TAL Bond was incorporated as a total water replacement in the adhesive and grout mixes for tiling to all floors, thus enhancing the flexibility and water resistance of the installation. To further accommodate movement within the project, intermediate tile panel movement joints and perimeter joints were installed to cater for the anticipated structural, background and thermal movements of the building, and were specified at 2.40 metre centres, to align with the modular tile sizes.
TAL’s Technical Consultants, Pelzer and Muzondida were on site throughout the project to ensure material was delivered timeously, provide product training on the application of TAL products, and to assist the contractors with queries and troubleshooting for both the waterproofing and tiling installation. TAL is proud to have contributed to this massive project and will continue playing an integral role in Africa’s tallest skyscraper.