Building envelope

The building envelope is a closed geometric structure and the physical separation between the inner and outer surroundings of a building . It comprises all components of a building that close it off from the outside. The outer shell is a barrier against precipitation , outside air , outside temperature , noise and radiation. The building envelope protects the internal facilities and installations together with the mechanical conditioning systems and supports the air conditioning .

The construction, dimensioning and design of building envelopes is the specialty of architecture and civil engineering .

construction

The building envelope is made up of components that separate the heated room from the outside climate and the unheated rooms. The physical components of the building envelope consist of the foundation , the walls , in them doors and windows , ceilings and the roof . The dimensions, properties and compatibility of materials, manufacturing processes and details, their assembly and interrelationship are the main factors that define the effectiveness and durability of the building waterproofing. The shell consists of several layers: base layer , thermal insulation layer , airtight and vapor barrier layer, moisture buffer layer and protective layer.

function

The heat-transferring surrounding area must meet changing thermal conditions and loads (such as wind and snow loads ) and the physical requirements of the building . In addition to the functional properties of the building envelope, there are also social and aesthetic properties: “As a transition between inside and outside - belonging to the house and urban space - the building envelope is of particular importance. It provides protection from wind and weather, demarcates property and provides privacy, but equally important is its aesthetic and cultural function. "In addition, there are still requirements for sustainability, energy efficiency and comfort.

The functions of the building envelope can be divided into:

Support function (to withstand mechanical loads and dissipate them)
Control function (of the material and energy flow)
Building closure ( to enable controlled heating and air conditioning in the interior )

To achieve these goals, all building envelopes must have a load-bearing structure. A water-repellent layer is required to protect against soaking. Buildings with common rooms for people and animals or for the storage of sensitive goods also require an airtight layer, a thermal barrier and a vapor barrier , depending on the climate and requirements . Controlled air flow is important in order to guarantee pleasant air quality in the building, to limit energy consumption, to prevent condensation through convective moisture transport and to ensure comfortable indoor air . Sealing against moisture (e.g. through horizontal barriers ) is crucial, especially in cold and hot and humid climates.

Up until the end of the 20th century, commercial and residential buildings also had a more or less leaky building envelope . With efforts to achieve a better building energy balance, the ventilation heat losses due to uncontrolled free ventilation through openings in the building envelope (see also joint ventilation ) became the focus and the aim is now to achieve a tight building envelope .

The blower door test is now often used in new buildings to check the tightness of the building envelope . Thermal imaging cameras are used in the thermography of building envelopes in order to make temperature anomalies of the inner and outer surfaces visible by analyzing the infrared image, to identify leaks and cold bridges and to detect condensation.

literature

Michael Hladik: Focus on the building envelope: planning - construction - execution - technology - structural damage. Fraunhofer IRB Verlag, August 27, 2012, ISBN 978-3-8167-8166-0 .

Individual evidence

↑ Jeff Wilson: The Greened House Effect: Renovating Your Home with a Deep Energy Retrofit . Chelsea Green Publishing, 2013, ISBN 978-1-60358-450-0 , pp. 42 .
↑ Christian Schittich, Walter de Gruyter: building envelope . Birkhäuser Verlag GmbH, 2012, ISBN 978-3-03821-338-3 , p. 9 .
^ John Straube, Eric Burnett: Building Science for Building Enclosures . Building Science Press, Westford, 2005, 549 pages, ISBN 978-0-9755127-4-6 .

[Wilson_2013-1] Jeff Wilson: The Greened House Effect: Renovating Your Home with a Deep Energy Retrofit . Chelsea Green Publishing, 2013, ISBN 978-1-60358-450-0 , pp. 42 .

[Schittich-2] Christian Schittich, Walter de Gruyter: building envelope . Birkhäuser Verlag GmbH, 2012, ISBN 978-3-03821-338-3 , p. 9 .

[3] John Straube, Eric Burnett: Building Science for Building Enclosures . Building Science Press, Westford, 2005, 549 pages, ISBN 978-0-9755127-4-6 .