In the case of waterproofing of components in contact with the ground in the form of a "black trough", the components only become waterproof through additional measures in the form of external coatings.

In contrast to the sealing of components in contact with the ground with a white tank, components with external sealing can be manufactured to be vapour-tight, so that they are often used when the rooms behind them are used to a high standard.

More about waterproofing with black trough

DIN

18533 must be applied to the waterproofing of components in contact with the ground. It can be used on reinforced concrete walls and floor slabs, but also on brick basement walls. High-quality basement rooms must be permanently protected against moisture. The above-mentioned seals also ensure sufficient tightness in terms of water vapour diffusion. The planner must first determine the correct water impact class (see lexicon article ►Water impact classes according to DIN 18533-1). All sealing measures must then be coordinated with this. The load case soil moisture and non-pressing water must always be assumed as a minimum requirement for all building waterproofing, unless there are further requirements. The basis for decision-making listed in the matrix in the above-mentioned encyclopedia article can be determined by a geotechnical expert report in accordance with DIN 4020.

Notes on the planning

of plinth sealing: The wall plinth of single- and double-shell masonry must be sealed in accordance with DIN 18533-1, Sections 5.1.5 and 8.8 (water exposure class W4-E), unless pressing water is to be expected, e.g. in the event of a high design water level. In the construction state , the waterproofing must be carried out from approx. 20 cm below to approx. 30 cm above the ground surface (GOK). The elevation above the ground surface should never fall below a height of 15 cm, even in the final state . Further specifications and example details can be found in DIN 18533-1 Section 8.8.

Cross-sectional sealing: DIN 18533-1 Section 8.8 also regulates the necessity and execution of additional cross-sectional waterproofing in the base area of external walls and under interior walls if the substrate and the affected walls are capillary conductive. A horizontal seal (cross-sectional sealing) is provided below the walls, which connects to the vertical plinth sealing in the outdoor area. DIN 18533-1 Section 8.8 also contains further specifications and example details.

Connection to the floor slab: In the case of pressurized water, the wall and floor waterproofing must form a closed tub together. For this purpose, an external cove is formed. When the wall waterproofing transitions to a waterproof floor slab, the waterproofing must be guided at least 15 cm below the upper edge of the floor slab. If the water column is > 3 m (W2.2-E), the waterproofing must no longer be connected directly (adhesively) to the waterproof component, but via a built-in component that is installed to protect it from the rear flow, e.g. a weld-on flange. Specifications and example details on the transition between floor and wall waterproofing are contained in DIN 18533-1 Sections 9.1 and 9.2.

Door connection: In the case of patio doors or house entrances, etc., the penetration of water or the backflow of the waterproofing must be prevented by guiding the waterproofing at least 15 cm above the water-bearing level. This dimension can be reduced, for example, for barrier-free house entrances if additional measures are taken, such as drainage channels or large canopies. Running of the seal must be prevented, e.g. by a watertight connection of the seal to the door threshold by means of a clamping profile. Specifications and example details can be found in DIN 18533-1 Section 9.3.

Penetrations: The following minimum distances must be observed for adhesive flanges, weld-on flanges and sleeves (from the outer boundary of the flange or sleeve), unless larger distances are required for processing reasons:

≥ 15 cm distance from each other and from other components, e.g. to building edges/grooves and wall connections,
≥ 30 cm distance to movement joints.

For loose and fixed flange constructions, larger minimum distances (from the outer edge) must be observed in the following cases:

≥ 30 cm distance to building edges/grooves,
≥ 50 cm distance to movement joints.

If these minimum distances are not met, a special construction must be planned for the waterproofing. In the case of W2-E, penetrations, e.g. pipe penetrations, drains or anchorages, must be located as far as possible above the design water level. Specifications and example details on penetrations can be found in DIN 18533-1 Section 10.

Movement joints: Depending on the type of joint, movement joints must already be taken into account during planning in accordance with DIN 18533-1, sections 4.4 and 11. Depending on the material, the design is carried out in accordance with DIN 18533-2 (for membrane-shaped waterproofing materials) or according to DIN 18533-3 (for waterproofing materials to be processed in liquids).

Radon radiation: A black tub significantly reduces the input of natural radon radiation from the ground. Radon is a colourless, odourless and tasteless radioactive noble gas that occurs everywhere in nature, albeit locally in very different concentrations. According to a letter from the Bavarian State Agency for Environmental Protection, radon and the associated decay products are the second most common cause of lung cancer after smoking.

According to

DIN 18533-1, the subsoil for building waterproofing in contact with the ground must comply with the following properties: frost-free, firm, even, free of nests, gaping cracks and burrs, free of damaging impurities. The moisture content of the substrate must be matched to the waterproofing system and must not exceed its permissible level. Other requirements for the substrate also depend on the waterproofing materials chosen. Waterproofing materials to be processed in liquid form usually have higher requirements for the substrate than membrane-shaped waterproofing materials, e.g. unevenness, depressions, open butt and bearing joints or breakouts have to be closed or compensated for. Specific requirements result from DIN 18533-2 Section 4.2 (for membrane waterproofing materials) or DIN 18533-3 Section 4.2 (for waterproofing materials to be processed in liquids).

Basement ceiling connection: Often, the basement ceiling is only concreted after the external waterproofing and perimeter insulation have been applied, because then the perimeter insulation is used as the front formwork. However, this means that the front of the blanket is without protection against moisture ingress. In connection with a black trough, a slab edge formwork should therefore be used and the waterproofing should only be applied to the front side of the slab after the ceiling has been concreted.

Layer thickness of waterproofing materials to be processed in liquid: In order to ensure the required minimum dry layer thickness, a layer thickness surcharge is required during application, which must be specified by the manufacturer for the respective application and which must be taken into account in the wet layer thickness to be applied. Compliance with the required layer thickness must be checked, e.g. by means of procedures in accordance with DIN EN ISO 2808 and in accordance with the instructions in DIN 18195 Supplement 2.

Protection: To protect the waterproofing, a protective layer must be created on the outside, for example in the form of perimeter insulation, a dimpled film or a drainage mat. The protective layer must be applied immediately after completion of the waterproofing, unless temporary protective measures have been taken during the construction period.

Weather influences: The seals are sensitive to rain, frost and direct sun when fresh. For this reason, suitable weather conditions must be ensured during the waterproofing work, taking into account the manufacturer's instructions.

Standards and Literature

DIN 18195 Waterproofing of Structures - Terms

DIN 18533 Waterproofing of Components in Contact with the Ground:

Part 1: Requirements, Planning and Implementation Principles
Part 2: Waterproofing with Membrane Waterproofing Materials
Part 3: Waterproofing with Waterproofing Materials to Be Processed in Liquid Liquid Sealing

Materials

DIN 4095Subsoil; drainage for the protection of structural facilities; Planning, Design and Execution

Guideline for the Planning and Execution of Waterproofing with Plastic-Modified Bitumen Thick Coatings (KMB Directive), published by Deutsche Bauchemie, May 2010

WTA Leaflet 4-6-14/D Subsequent Sealing of Components in Contact with the Earth, published by the Scientific-Technical Working Group for Building Preservation and Monument Preservation e.V., November 2014

Source: bauwion

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