|
|
 |
 |
Hotel de Rome, Berlin |
|
|
Hotel de Rome, Berlin | A shining example of how to lay large-format coverings
|
The Hotel de Rome, a new, imposing five-star establishment, stands at the heart of Berlin's historic centre, fronting the Bebelplatz square, formerly the Forum Fredericianum. Operated by British hotel magnate Sir Rocco Forte, the hotel occupies a Gründerzeit building constructed between 1887 and 1889 to the designs of architect Ludwig Heim. Having served as the headquarters of the Dresdner Bank until 1945, it then became the nerve centre of the East German State Bank. The building's neo-classical exterior is a particular eye-catcher. Inside, the hotel has a modern, though still palatial feel, having retained the charm of times long past. The interior design was developed by Italian architect Tommaso Ziffer, highly acclaimed for his Hotel Russie scheme in Rome. Assisted by designer Olga Polizzi, he successfully enriched the classical architecture of the prestigious building with contemporary stylistic features.
|  |
The soft interior refurbishment gave the marble columns, terrazzo floors, mosaics and murals a new lease of life. The old oak stairways, iron balustrades, woodwork and fibrous plaster decoration were sensitively restored. The magnificent architecture effortlessly blends historic and modern features into a stylish, balanced ensemble. Showpiece elements of the original neo-classical building were carefully preserved: the spacious foyer of the former bank now serves as a majestic hotel lobby, with integrated reception, bar and restaurant. A further stunning focus at ground-floor level is the double-height former counter hall, which has been converted into the splendid, over 270 m² Palm Court ballroom.
Under its historic roof, the grand building houses a total of 146 rooms, including 72 in the Classic and 29 in the Deluxe category, together with nine Executive suites, three Deluxe suites and a breathtaking Presidential suite. The suites on the first floor, the former boardroom level, are particularly popular with visitors. Closed off by soundproof double doors, these still feature the original wood panelling scarred by shrapnel from the Second World War.
| |
|
The materials specified by the client and design team for the refurbishment were subject to the highest demands in terms of quality and aesthetic impact. Thus, the bathrooms in the over 100 rooms were lined with full-height, large-format natural stone units. The different types of incorporated stone include a black Nero Assoluto basalt and stone mosaic finishes. Prior to installation of the coverings, the substrates were levelled out, primed and damp-proofed with a Sopro FDF or Sopro DSF membrane compliant with ZDB (Federation of the German Construction Industry) data sheet "Guidance on indoor and outdoor installation of composite waterproofing systems with tile finish" (January 2005 edition). The stone slabs specified by the client demanded special preparatory measures prior to laying. Indeed, as a general rule, contractors should always factor such works into their tenders to avoid a financial debacle.
Experience shows that large stone slabs cannot be readily laid on previously constructed screed and plasterwork substrates, even where these are standards-compliant. The fact that even the enhanced requirements to the relevant German standard (DIN 18202) are inadequate for the laying of large-format units invariably necessitates additional preparation. The new DIN 18157 ceramic finishes standard will include procedural details that address this problem. For tilelayers, this means that tenders should always include a "levelling/surface filling" item to ensure provision of an even substrate.
When installing floor coverings, tilelayers may encounter various types of screed. The check required in each case on the screed's readiness for flooring installation, i.e. its residual moisture, involves the use of a so-called CM tester. The permissible residual moisture for cement screeds is 2% and for calcium sulphate-based screeds 0.5% (unheated) or 0.3% (heated). Other factors that require analysis in determining the suitability of a substrate for large-format slab finishes include surface strength, bay size and movement joint design.
Particular caution is required where large-format units are laid on calcium sulphate-based screeds. With these applications, the number of cases involving adhesion failure has spiralled in the recent past. Such failures are possibly traceable to the very low relative area of the joints and the generally impervious covering materials (e.g. fully vitrified stoneware). This means that the moisture in the bedding mortar cannot diffuse from the floor construction as rapidly as required. This triggers a migration of moisture into the upper zone of the calcium sulphate-based screed, thereby impairing its surface strength. Any later thermal stresses due to temperature fluctuation, for instance, may then bring about shear failure of the covering in this weakened zone. It is therefore advisable to seal off calcium sulphate-based screeds, using a reaction resin primer, prior to the installation of large-format coverings. This measure is appropriate even for tiles as small as 40 x 40 cm. Pretreatment with Sopro EPG 522 epoxy primer is recommended. The freshly applied coat is then blinded with Sopro QS 511 coarse silica sand.
After the substrate has been levelled and, where necessary sealed as described above, the coverings can be laid in a thin bed of Sopro VF 411 VarioFlex® adhesive for marble tiles. This adhesive can also be applied with a medium-bed trowel. Due to its high sag resistance, Sopro's No.1 white rapid-set flexible tile adhesive is recommended for natural stone wall finishes. As a general rule, a butter coat should be applied to the rear face of large-format units prior to installation to prevent air entrapment and any possible light/dark patchiness. Certain types of natural stone and artificial covering materials are prone to dishing when laid. In cases of uncertainty, the building chemicals manufacturer alone can provide a tailored recommendation and should always be consulted
| |
|
Thicker, 10-20/25 mm mortar beds are generally required to achieve a level finish with particularly thick and heavy large-format stone coverings. Such applications require a bedding mortar such as Sopro MDM 888 medium-/thick-bed tile adhesive. This offers adequate sag resistance to accommodate heavy units even in beds as thick as 20-30 mm without downward deflection or escape of mortar at the joints. A self-supporting thick-bed solution (floating construction) is not advisable for large-format coverings due to the possible exposure to high live loads. This is because thick-bed constructions, unlike screeds, have no clearly defined compressive or tensile strengths. The joints in the fully installed covering were finished with Sopro Saphir® M water-repellent marble grout.
| Featured Sopro products:
|
|
|
 |
|
