External thermal insulation composite system (ETICS) describes a multi-layer insulation system for exterior walls. It is also colloquially known as full thermal insulation or thermal skin and can be used for renovation on existing walls but also in new buildings. An ETICS usually consists of the layers of insulation material, reinforcement layer, reinforcement fabric, façade plaster and façade paint.
Types of ETICS:
Image: PUR boards - bauwion
Image: Mineral foam boards - bauwion
Image: Wood fibre insulation boards - bauwion
Image: Brick façade insulation - bauwion
Image: Mineral wool panels - bauwion
Image: Mineral wool slats - bauwion
Image: EPS panels - bauwion
manufacturer's processing instructions must be observed in any case. The layers, including paint, must be coordinated with each other and may only be carried out as a jointly approved system. A wide variety of materials are used for both the insulation materials and the plaster layer. The available space requirements should be taken into account at an early planning stage. Better insulating systems, e.g. made of PUR, require less space with the same insulating effect as other systems. However, other factors are just as important, especially the fire protection requirements and the fastening substrate.
offastening/substrate: Existing plasters and coatings must be checked for strength and cavities as well as load-bearing capacity, non-load-bearing areas must be completely removed. Larger protruding mortar or concrete parts must be knocked off, and larger unevenness in the substrate must be levelled out with suitable mortar, e.g. plaster of the mortar group PII.
The following fastening options are generally available for attaching an ETICS to the substrate (load-bearing wall):
Depending on the system, combinations of the individual fastening options are also required, e.g. simultaneous bonding and doweling.
A rail fastening system is particularly suitable for a substrate with larger unevenness and/or with non-load-bearing coatings, i.e. mainly for the renovation of existing buildings. However, due to the disadvantages (usually higher price, greater thermal bridge influences), it should be checked in each individual case whether bonding + dowel is also an option. In many cases, pure bonding without additional anchoring is possible in new buildings depending on the insulation material, the tear-off resistance of the substrate and the wind suction to be applied, more information can be found from the respective manufacturer. For the anchoring, the number/arrangement of the required dowels may have to be found out from the respective manufacturer, taking into account the relevant factors according to DIN 1055-4 such as wind zone, building height, height above sea level and the ratio of height to width of the building. This also determines whether the calculation can be carried out in a simplified procedure or whether the exact number of dowels must be calculated in each individual case.
Water vapour permeability: When applying a coating, the water vapour permeability of the coating must always be compared to that of the top plaster (► 303 | exterior plaster-top plaster), whereby the coating must be more vapor-permeable than the top plaster underneath .
Surface colour, light reference value: A dark colour scheme is only possible to a limited extent in a thermal insulation composite system . The decisive factor here is the so-called light reference value. If this is below 20%, sunlight leads to increased thermal effects on the façade surface and thus to increased stresses in the reinforcing and plaster layer, which can lead to cracking. In addition to the light reference value , the degree of exposure to the sun, the material of the external thermal insulation composite system (organic systems are less prone to cracking than mineral systems in this context) and the size of the affected façade surfaces (large surfaces also have greater stresses than smaller ones) also play a role. If the external thermal insulation composite system is to have a dark surface (light reference value <20%), the basic feasibility must therefore be clarified in consultation with the manufacturer and, if necessary, what additional measures (e.g. multiple coat of paint, additional reinforcement measures, organic coating) must be taken.
Reinforcement: Subsequent reinforcement measures give the external thermal insulation composite system its stability. Basically, a reinforcement compound is applied in which the reinforcement fabric is inserted into the wet reinforcement compound, in the case of surface reinforcement as a sheet product, at corner points, e.g. as fabric molded parts with corner protection rails.
Expansion joints: In principle, building-related separation joints (expansion joints) must be incorporated into the external thermal insulation composite system . The joint is closed to the outside, for example, by means of expanding joint sealing tapes or special ETICS expansion joint profiles. Depending on the insulation thickness, it may be necessary to backfill the area behind the profile or sealing tape with mineral wool. In the area of fire walls, a strip of non-combustible insulation material must be arranged on both sides of combustible insulation layers, which must be glued to the substrate over the entire surface. The strip width must at least correspond to the thickness of the fire wall and be at least 10 cm on each side of the joint, and the area behind the profile or expansion joint tape must also be completely filled with mineral wool in any case. The plaster in the area of the strip must not be produced with flammable organic products.
EIFS in splash water areas: Façade areas that are located directly above horizontal water-bearing levels, e.g. above the site or over balconies/roof terraces, are exposed to increased mechanical and moisture-related loads. In the plinth area, there is the possibility of forming a recessed plinth, in which the external thermal insulation composite system ends well above the water-bearing layer and ends at the bottom with a plinth rail. The disadvantage of this variant is the interruption of the external insulation, so the effects must be critically examined in terms of energy, with regard to the risk of condensation and compliance with the minimum thermal insulation.
Alternatively, the perimeter insulation can be led from the ground to the external thermal insulation composite system , or special plinth insulation boards can be used. The insulation is then provided with a splash-resistant plaster system approved for use in the plinth area or appropriate coatings.
In the case of splash water areas of buildings for which non-combustible façade cladding is prescribed, e.g. in special buildings such as high-rise buildings, it must be checked on a case-by-case basis whether and, if so, to what extent the use of (combustible) plinth insulation boards is possible. In most cases, this is limited to a strip of no more than 60 cm high, which must be provided with a mineral plaster.
Mounting elements: In order to enable the fastening of individual loads in the external thermal insulation composite system , there are various system components depending on the manufacturer. For small loads such as signage and bells, special spiral-shaped mounting anchors are usually sufficient, for larger loads there are, for example, pressure-resistant polystyrene cuboids or components made of rigid PU foam with foamed-in metal plates, which are integrated into the insulation level and are largely invisible in the finished state.
Fastenings that have to be statically verified, e.g. for balcony railings, may not usually be attached to these elements.
Renovation of existing facades: Existing buildings can generally be renovated well with an ETICS, the design possibilities are very large, and in terms of energy and appearance, the renovated facades can come very close to a new building. The additional space required for the ETICS façade must be taken into account. Existing external thermal insulation composite systems can also be doubled up at a later date for an improved insulating effect. In this case, the new external thermal insulation composite system must be anchored through the existing ETICS in the load-bearing outer wall. In addition, the manufacturer's specifications for the design details must be observed, e.g. with regard to permissible (total) insulation thicknesses, and with regard to the (possibly subsequently necessary) installation of fire bolts in the area of window lintels or roller shutter boxes.
Is the subsequent insulation of an existing exterior wall subject to approval? The individual state building codes contain different requirements for this. In Bavaria, for example, "exterior wall cladding, including thermal insulation measures, except for high-rise buildings, cladding and plastering of structural facilities" are generally exempt from proceedings (Bavarian Building Code Art. 57 para. 1 no. 11e).
In any case, however, compliance with substantive requirements (e.g. compliance with distance areas, property boundaries and building boundaries/building lines, extent of structural use) must be observed. These result in particular from the state building code and from the development plan, if available. The permissibility of reducing the clear width of passages/passages (escape route widths!) must also be examined if necessary.
The increased building volume due to the external wall insulation and the changed position of the façade level(s) must therefore always be checked by an expert, e.g. an architect, with regard to building law effects. Depending on the facts, this may require the building supervisory approval of a deviation from the state building code and/or an exception or exemption from the development plan.
Lightning protection: The installation of lightning protection systems is regulated in the DIN VDE series of standards 0185-305-1 to 0185-305-4 including all supplements, but there is no specification as to whether lightning rods may be laid within a thermal insulation composite system. This must therefore be checked in each individual case by the responsible planner in consultation with the ETICS manufacturer, also with regard to the installation conditions (inspection flap in the area of terminal points, wall distance of the lightning protection cables), but laying outside the ETICS is generally preferable. The installation of the entire lightning protection system must always be carried out by an authorised specialist company, taking into account the relevant legal provisions.
Fire protection: The state building codes contain stipulations on fire protection requirements for exterior walls and façades, in each case depending on the building class and, if applicable, supplemented by other regulations such as a garage ordinance or a special building regulation.
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conditions: In the event of unsuitable weather conditions, such as strong sunlight, precipitation and temperatures below 5°C during bonding work, additional suitable measures may be necessary, which the executing company must take in coordination with the client and for which it is entitled to a separate remuneration in accordance with DIN 18345 (VOB C) No. 3.1.3.
Measurement and invoicing: DIN 18345 (VOB C) must be observed for the preparation of the service description and the measurement, but also for the billing, in particular sections 0 ("Notes for the preparation of the service description") and 5 ("Invoicing").
Note: DIN 4108-1 (Thermal insulation in building construction; Sizes and units) has been withdrawn and replaced by DIN EN ISO 7345
DIN 4108 Supplement 2, Thermal insulation and energy saving in buildings - Thermal bridges - Planning and execution examples
DIN 4108-2, Thermal insulation and energy saving in buildings - Part 2: Minimum requirements for thermal insulation
DIN 4108-10, Thermal insulation and energy saving in buildings - Part 10: Application-related requirements for thermal insulation materials - Factory-made thermal insulation materials
DIN 18345, VOB Part C, General Technical Contract Conditions for Construction Services (ATV) External Thermal Insulation Composite Systems
DIN 18363, VOB Part C, General Technical Terms and Conditions of Contract for Construction Services (ATV) Painting and varnishing work - Coatings
DIN V 18550, Pre-standard , Plaster and plaster systems - Execution
DIN 18558, Synthetic resin plasters; Definitions, requirements, execution
DIN 55699, Processing of external thermal insulation composite systems
DIN EN 13162, Thermal insulation materials for buildings - Factory-made products made of mineral wool (MW) - Specification
DIN EN 13163, Thermal insulation products for buildings - Factory-made products made of expanded polystyrene (EPS) - Specification
DIN EN 13165, Thermal insulation products for buildings - Factory-made products made of rigid polyurethane foam (PU) - Specification
DIN EN 13171, Thermal insulation products for buildings - Factory-made products made of wood fibres (WF) - Specification
DIN EN 13499, Thermal insulation products for buildings - Exterior thermal insulation composite systems (ETICS) made of expanded polystyrene - Specification
DIN EN 13500, Thermal Insulation Materials for Buildings - External Thermal Insulation Composite Systems (ETICS) made of Mineral Wool - Specification
DIN EN ISO 7345, Thermal Insulation - Physical Quantities and Definitions
EnEV - Energy Saving Ordinance for Buildings, Ordinance on Energy-Saving Thermal Insulation and Energy-Saving System Technology for Buildings
Source: bauwion
