Window glazing is usually the most neglected part of the building. Most architects and investors primarily deal with the appearance of the window and the function and material of window frames in an effort to minimize heat loss in window openings and meet the conditions imposed on buildings within the framework of the amendment for almost all zero-energy buildings.

Glass is, however, an indispensable part of every window pane, from which it makes up 85%! The design of windows and glass should be defined clearly and comprehensibly in the project documentation for the construction. It is the specific positioning of the window, the orientation of the object and the maximum size of the glass surface that are the determining factor for correct and informed selection of the window. And it is necessary to add that the definition of triple glazing with Ug = XY, which is often used in the project, is totally insufficient.

Choosing the right glass

The window, from a thermal insulation point of view is often considered to be the weakest link in the perimeter cladding, should be an integral part of the design of the entire structure from the very beginning. Especially glazing; it is part of the construction product and is subject to laboratory and computing assessment procedures. Requirements for glass and opaque fillings are determined by the specific design of the product, the place of installation in the building and the system principles. The properties given to it during production will subsequently define not only its energy efficiency during construction, but also the internal environment of the building and the feeling that users will have inside. That is why the cooperation of specialists from several areas is necessary already during the design of glass and any order should therefore be preceded by carefully and well-processed project documentation, which clearly defines which types of glass will be used in which parts of the house. From the point of safety, protection against noise and heat leakage and, of course, the volume of transmitted natural light and heat moving into the interior, it can be clearly stated that there are requirements for different types of glazing in the building and therefore it is impossible to use the same type of glass in all windows.

What should an architect or designer know?

In order to achieve a quality and well-lit interior, the architect and designer should work effectively not only with the size of the window, but also with its properties.

The key questions in choosing correct and suitable windows are the following:

• What are the client’s requirements for acoustics and airborne sound insulation Rw [dB]?
• What is the orientation of the object with respect to the cardinal points of the world?
• How will sun protection be solved in the building? Are outdoor blinds planned? Is it even possible to install blinds?
• What is the client’s requirement for light transmission TL [%]?
• What are the client’s expectations regarding visible external reflection Lr [%]?
• What are the security requirements – either from the client’s point of view or with regards to security?
• What are the requirements for the heat transfer through the glass, what heat transfer coefficient Ug through the glass is required and what is the required coefficient Uw for the whole window [W/m²K]?

Why is it necessary to start with acoustics?

Acoustics indirectly define the thickness of the glass and thus the desired profile. Unfortunately, it is never possible to choose glass that offers only the pluses – that means that it transmits light, but no heat. There is always a compromise to be reached. That is why when choosing each window in the house, it is important to consider what is most important for the users of the particular room.

One of the reliable innovative solutions that offer such a compromise is so-called insulating glass with a new generation of low-emission ECLAZ coatings from Saint-Gobain. Thanks to the innovative coating technology, insulating glass achieves above-average thermal insulation properties, high light transmission as well as high solar gains.

Glass as part of savings

So, it can be concluded that an ideal and correctly installed window with appropriately selected glass and quality frame should, depending on the orientation of the building, let into the interior as much light as possible, as much heat from the sun as possible and have the best possible thermal insulation properties – all under the assumption of functional exterior shielding. In short, it can be said that according to the strictest criteria at nZEB, the building cannot do without high-quality windows with responsibly and correctly selected glass specified on the basis of the expected properties.

PR

The gap site between Verdunská and Jugoslávských partyzánů streets in Prague – Dejvice, near Vítězné Square, will take on a new shape. Or more precisely, it will vanish.

At the beginning of July, the building authority for Prague 6 issued a permit for the construction of Victoria Palace, a residential building to be built there by the development consortium of Penta Real Estate and Kaprain. This will end almost a century of groping around as to what to do with the place that is part of the valued concept of Vítězné (Victory) Square by the architect Engel from the 1920s. His vision was a modern cut of the north-western city modelled on the reconstruction of Paris in the 19^th century; The Vítězné Square was to be the centre of events with a well-thought-out
arrangement of buildings in a circular floor plan. Due to the economic crisis and the World War II, only a torso remained from the original idea. It was not until 2010 that the LINE project by architect Radan Hubička, who developed it for PPF, was to change the location of today’s gap site. Whilst primarily the office building won the award as the project of 2013, the public nor some experts accepted it, though. The building permit for Victoria Palace therefore makes it possible, after many decades, to complete the missing piece of the story of the architectural change for the entire centre of Prague 6.

With respect to history

The architectural studio Jakub Cigler Architekti (JCA) suggested for the gap site a residential building that would represent an elegant modern realization of the original idea regarding the appearance of this part of the square. According to Engel’s concept, the building in today’s gap site was to be the axial counterpart of the Army General Staff building. In the plans, the two buildings were the same, only mirror-inverted.

Victoria Palace adheres to the original lines in the JCA design. The building of the General Staff and the modern residential house will be connected by similar elements, with the fundamental difference being within their conception by architects, who are about 90 years apart. Victoria Palace is really a mirror counterpart of the General Staff Building. The facades of both buildings have a significant vertical division. The main ledge is at the same height as the ledge of the General Staff building and in the upshot as the ledges of the surrounding buildings in the square. The saddle shape of the Victoria Palace roof formed by slats is a copy of the roof of the General Staff building. One would find a number of common elements in both buildings and also other houses in Vítězné Square.

Victoria with an overview

The Penta Real Estate and Kaprain consortium will build a nine-storey building in Vítězné Square for about a billion crowns. The building will come with a total of 97 flats, two underground floors for technical facilities, cellars and mainly 135 parking spaces. This will thus create 7,200 sq m of living space and 1,800 sq m for retail and services in an area of over 4,200 sq m. According to the requirements of the city district, there will be a supermarket, a pharmacy, a bank branch and also a mobile network operator. The apartments will be among the top offers in the capital. The larger one’s face both sides of the building – i. e. the square and the peaceful zone of a courtyard. The vast majority then come with outdoor loggias or terraces. This category of apartments is characterized by a high proportion of natural materials, and premium brands come as a matter of course with regards to the equipment. The open glazed facade divided by vertical lamellas, which is the dominant element of the building, allows a rich transmission of light into the interior of all residential units. “We have a number of higher standard residential projects that are of greatest interest in the market under construction,” says David Musil, Residential Development Manager at Penta Real Estate, adding: “Victoria is a different story. It has the same character as Trafalgar Square in London or the Leipziger Platz in Berlin. Places that do not fall asleep. Victoria represents exceptional housing in Prague, for which the price corresponds.” The apartments will be put on for sale in the near future. According to preliminary information, the price of a studio apartment, i. e. 33 sq m bedsit with kitchenette, exceeds CZK 7 million. The very best that Victoria has to offer are four penthouses situated on the top two floors, with sizes ranging from 130 to 202 sq m and terraces from 80 to 236 sq m. These apartments, for which their future owners can get directly from an elevator, will require tens of millions of Czech crowns.

A private garden in the courtyard will be available for the apartment owners; It is almost pointless to emphasize that it will come with trees, plenty of greenery and a water feature. This is just another of the benefits that are obvious to anyone who knows Prague: Victoria Palace will become part of the centre of the Prague location, which is characteristic for traditional residential functions in highly regarded areas, such as Ořechovka, Hanspaulka and the area surrounding Vítězné Square. Prague 6 alone is a city district with large green areas, to which we can also include a part of Prague’s Stromovka. It is no coincidence that this part of Prague has been chosen by a number of countries for their embassies. Victoria Palace is located close to the underground and Václav Havel Airport is also easily accessible.

Penta Real Estate has currently started preparing a building site and the Victoria Palace residence should be completed before the fourth quarter of 2023.

PR