The Stavros Niarchos Foundation Cultural Center

Canal Waterproofing

The new canal in the park was waterproofed using a reinforced, built-up Sika sheet membrane system inside the new structure. This Sika system also enabled the engineers to ensure fully watertight connections, joints and terminations, by connecting it directly to the retaining concrete structures using Sika® Waterbars and Sika engineered waterstops. Sikaplan® membrane was selected in order to ensure the complete water tightness of the canal construction and the roughly 15,000 cubic meters of water it contains.

Below Ground Waterproofing

In a project of this magnitude, waterproofing below ground to protect the structural foundations and create a water resistant structure was of utmost importance. The Sika watertight concrete system for below-grade structures included:

• Waterproof concrete prepared using special Sika water resisting admixtures
• Sika engineered jointing systems, including Sika® Waterbars, plus additional Sika waterstops, such as SikaSwell®-A water swelling profiles
• Built-up Sikaplan® WP-1100 15HL sheet waterproofing system, incorporating geotextiles and integral drainage layer for the deep basement
  
• Special SikaFuko® VT-1 injection hoses for easy re-injection and sealing in case of any future ground movement at the diaphragm walls
  

Structural and Architectural Concrete

Approximately 150,000 m³ of 10 different classes of structural and architectural concrete with different technical characteristics were required. Technical performance and placement along with architectural concrete (especially fair-faced area) aesthetic requirements - uniform color and smoothness - had to be met. Sika admixtures were incorporated into all concrete mixes. Final fair-faced concrete mix designs were based on self compacting concrete using Sika® ViscoCrete® Ultra-600 superplasticizers with Sika® Stabilizer®-4R viscosity modifiers. Sika® Separol® W-320 and Antisol® systems were used for demolding and controlled water evaporation from curing concrete surfaces.

Seismic Isolation Systems

The new opera and library buildings are built on specially designed seismic isolation systems placed between vertical bearing elements and building foundations. These seismic isolators form an alternative, practical method for the seismic reinforcement, as they can significantly reduce the stress that the structure would be subjected to in an earthquake. For the seismic isolator installation, a special one-component, fiber reinforced, cementitious grout from the SikaGrout®-312 RFA range was selected.

Roof Waterproofing

For all flat roofs on this project, the most appropriate system was selected from the fully comprehensive Sika range of roof deck waterproofing systems. For the single-ply membrane roof build-ups, this was Sarnafil® TG 66-20 - multilayer, anti-root, synthetic roof waterproofing sheet based on premium-quality flexible polyolefins (FPO), reinforced with an inlay of non-woven glass fabric according to EN 13956.

Ferrocement Canopy Method

The new Greek National Opera building is covered by a huge canopy envisioned by the architect to hover above like a cloud, being both part of it and separate at the same time. This fabulous feature is one of the most important elements of the project design, both architecturally and structurally. This canopy had to be lightweight and compact with a perfectly smooth and continuous surface, which led to the selection of an unusual material for the canopy - ferro-cement. Ferro-cement is a thin, composite material that can be easily molded for lightweight structures, but not normally done on this scale nor for such structural applications. The Stavros Niarchos Cultural Center construction project was the first time worldwide that it was used for building on this scale, especially as a structural element!

For such high quality ferrocement construction, the design and performance of the cement mortar was of critical importance. Sika engineers and concrete technicians provided assistance from the very beginning through to successful completion on site - including detailed raw material analysis, mix design and testing in the laboratory and on site.

Ferrocement Canopy Waterproofing

The 10,000 m² ferrocement canopy itself was a unique, pioneering project. The selected waterproofing system was liquid applied, polyurea resin-based membrane system Sikalastic®-8800, which was spray applied onto the primed surface using two-component, hot spray equipment. A protective, polyurethane resin-based, highly UV resistant, top coating of SikaCor® EG-5 was then applied. Finally, the waterproofed surface of the ferrocement canopy was covered with photovoltaic panels, which contribute to the project's sustainability, significantly reducing its CO₂ footprint.

Car Parking Garage Flooring

The multi-story, underground visitor parking facility with about 40,000 m² of dedicated parking spaces had concrete deck surfaces which needed protection from abrasion and wear. Polyurethane and epoxy deck coating systems from Sika were ideal and applied throughout the car park. A special Sika polyurethane resin-based system was specified - Sikafloor® MultiFlex PB-21 UV - which is a highly aesthetic, anti-slip, crack bridging flooring system featuring high resistance against abrasion and noise minimization qualities. On the parking area under the opera, the uniform color, epoxy roller-coating system Sikafloor® MultiDur ES-14 was applied. All Sikafloor® systems carry a LEED attestation regarding VOC content.

Elastic Sealing and Bonding

The use of highly aesthetic wood flooring was a must for the opera building and this was installed using the elastic, one-component, polyurethane resin adhesives from the SikaBond®-54/-52 Parquet range. All concrete floor joints and building facade joints in concrete substrates were sealed and made watertight using Sikaflex® WS-355 polyurethane resin-based sealants. Sealing the natural white marble stone floor and wall tile joints was done using a special one-component, silicone resin-based Sikasil® WS-355 sealant, which is approved for contact with natural stone and does not stain.