Rear-ventilated curtain wall

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As a back-ventilated curtain facade ( VHF ), also ventilated wall or curtain wall is called the construction a multi-layered exterior wall construction or facade . The outer facade cladding protects the building structure from rain, snow and sun, but is usually rear-ventilated in order to be able to dissipate any moisture. If condensation is unlikely to occur, an airtight design is also possible.

In contrast to the curtain wall ( English rain screen cladding , rain protection panel ' ) is a curtain wall (engl. Curtain wall , curtain wall' ) is usually airtight and designed as a (partly) self-supporting facing shell, which is supported only at certain points to the building structure.

construction

System structure

The outermost layer, which protects against driving rain , is separated from the layers behind it by a layer of air . According to DIN 18516-1, the construction consists of the facade cladding, the rear ventilation zone, the insulation and the substructure. A statically supporting anchorage base is required. The thermal insulation is also ventilated from the rear to allow condensation to dry off.

The system allows a wide variety of facade claddings to be selected. Projects that are outstanding in terms of design, technology and economy have been awarded the German Façade Prize for rear-ventilated façades (VHF) by the trade association for rear-ventilated façades since 1999 .

The outermost layer (= facade cladding) can consist of wood , natural stone , artificial stone, ceramic, sheet metal (e.g. galvanized sheets or copper sheets ) or composite materials ( e.g. glass fiber concrete and fiber cement ) or even opaque glass.

Systems are even offered with which extensive facade greening can be realized.

Insects and possibly also rodents and bats should be prevented by grids from entering the rear ventilation zone at inlet and outlet openings. Recommended opening sizes for insect screens are 3 to 4 millimeters. With larger ones, the effectiveness decreases quickly, smaller ones clog quickly.

Technical regulations

Rear-ventilated curtain walls are regulated in DIN 18516-1 External wall cladding, rear-ventilated, Part 1: Requirements, test principles . Curtain walls and post / transom constructions are subject to the requirements of the DIN EN 13830 series of standards and have required a CE mark since 2005 .

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Advantages and disadvantages

A curtain wall is usually much more expensive than other external wall constructions such as thermal insulation composite systems . The surface of the thermal insulation on the outer facade cools down through heat radiation without a rapid replenishment of radiant heat from the sun, i.e. at night. When the temperature falls below the dew point, moisture from the air condenses on it, i.e. it is deposited on the surface and diffuses into the component through vapor diffusion or enters the insulating substance through capillaries, cracks or hairline cracks and is distributed in its pores through capillary action. If this moisture cannot dry out as a result, the building materials soak up moisture, they then conduct heat better and lose part of their thermal insulation effect. In addition, black mold and algae thrive in it. For these reasons, thermal insulation, especially those with pores and air cavities, are "rear-ventilated" to allow waterlogging to dry off, while the "rear ventilation" is behind the facade or facing brickwork that is hung in front of the insulation layer, i.e. between the outer layer and the insulation layer.

Incorrect processing of curtain façades can imply fire risks: in the case of a façade fire , a chimney effect can cause a lot of heat to collect in a short period of time and, thanks to the better buoyancy, air is sucked into the seat of the fire, and the curtain wall can also shield extinguishing water .

The separation of thermal insulation and weather protection implies advantages in terms of execution and design options.

Assembly

  • Step 1: Attaching the anchors in the grid of the support profiles

  • Step 2: Attaching the insulation, foil, support profiles

  • Step 3: attaching the facade cladding

  • Finished facade

Web links

Commons : Ventilated curtain walls  - collection of images, videos and audio files

Individual evidence

  1. ↑ Scott Hygnstrom: Prevention and control of wildlife damage . University of Nebraska Cooperative Extension, Institute of Agriculture and Natural Resources, University of Nebraska - Lincoln US Department of Agriculture, Animal and Plant Health Inspection Service, Animal Damage Control Great Plains Agricultural Council, Wildlife Committee, Lincoln Washington, DC Nebraska 1994, ISBN 978-0-9613015-1-4 , pp. D-20, OCLC 32081842 .
  2. ↑ Mike Guertin: Put a Rainscreen Intake Vent Over Windows and Doors . 18th May 2018.
  3. ↑ CMH Barritt: The Building Acts and Regulations applied . Longman Scientific & Technical, Harlow 1995, ISBN 0-582-27449-4 , p. 95, OCLC 60282122 .
  4. ↑ G. Hopfensperger et al: EnEV amendment 2009 and new heating costs ordinance. Verlag Rudolf Haufe, 2009, ISBN 978-3-448-09241-7 , p. 208.
  5. ↑ Calla Wahlquist: Cladding in London high-rise fire also blamed for 2014 Melbourne blaze . In: The Guardian . June 14, 2017, ISSN  0261-3077 ( theguardian.com [accessed June 15, 2017]).
  6. ↑ 'Firetrap' cladding on Grenfell Tower is BANNED in the US . In: The Sun . June 15, 2017 ( thesun.co.uk [accessed June 16, 2017]).
  7. ↑ G. Hopfensperger, among others: Renovating and modernizing for landlords. Verlag Rudolf Haufe, 2008, ISBN 978-3-448-07588-5 , p. 64.