Double facade

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Double facade with glass slats
Lower end of a double facade with ventilation openings

The double facade is a facade that has two facade levels. The outer level (secondary facade) has the function of absorbing environmental impacts such as solar heat input, wind loads (especially in tall buildings) or weather conditions . The inner level (primary façade) forms the end of the individual usable areas and usually also takes on the thermal insulation function . In between there is a space of min. 20 cm to several meters. A double facade can be designed either as an inlet or as an exhaust facade.

advantages

  • If the double façade is designed as a lamellar façade , it offers effective shading of a glass façade or windows behind it, especially against overheating of south-facing glass façades in summer
  • The space in between brings advantages for the air conditioning of the building, since the temperature of incoming outside air adapts to the inside temperature before it enters the individual areas of use. It is therefore possible to supply fresh air even at extreme temperatures.
  • Even in bad weather, the inner facade can be opened / left open from the usage areas.
  • Especially at higher altitudes, it is difficult to establish a connection to the outside world due to the wind forces that occur. The fact that the outer level breaks the air when entering the space means that the user can treat the inner facade to this as if it were a quiet inner courtyard .
  • The spaces in between can contain functions such as escape balconies or simply open spaces. Often there are also expansions in which common rooms can be integrated (also multi-storey).
  • The second skin provides additional sound insulation.

disadvantage

  • The execution entails not inconsiderable costs. However, the construction costs can be amortized over time through better air conditioning functions and thus lower operating costs.
  • The structure consumes floor space and thus limits the main usable area compared to the gross floor area . Especially relevant in cramped inner city situations with high property prices.
  • Double facades are often poor in terms of lighting technology, as cantilevered components and the second glass level absorb the daylight.
  • Risk of condensation forming.
  • Double facades often tend to "pump", i. This means that unsteady alternating currents arise in the space between the façades.

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Wiktionary: double facade  - explanations of meanings, word origins, synonyms, translations