A damp-proof course protect rising building walls from moisture which may rise in a capillary way from the ground through the foundations or the floor slab. The barrier is laid horizontally and is an indispensable component of the building structure. It not only prevents the penetration of rising moisture, but also the penetration of carried along and potentially damaging minerals and salts, coming from the soil and penetrating the interior part of the wall.
A standard application is the so-called horizontal barrier, inserted at the base of the wall to prevent moisture from rising vertically from the foundation into the walls.
Horizontal damp-proof courses may also be needed on the level or above the ground adjacent to the building. In case of double-shell exterior walls, these barriers are used to keep the moisture from driving rain and splashing water away from the insulation and the back wall shell at the base and through the wall openings. The front wall shell - the actual facade - protecting the building from driving rain is usually made of exposed masonry. The static load transfer is carried out by the rear shell. Between these shells there is the thermal insulation. Often there is an additional air gap used for the air circulation as well as for the dehumidification.
Horizontal barriers in basement walls are inserted between the floor slab and the first layer of stone during the construction of the outer and inner walls. Mechanically resistant and durable sealing sheets made of plastics or bitumen are suitable for this purpose. When laying, the bearing surfaces must be levelled out with the masonry mortar up to a thickness to guarantee a smooth and even surface.
Thanks to their robust and bitumen-compatible material, the products DELTA®-MAUERWERKSSPERRE or DELTA®-PROTEKT are ideal for the horizontal sealing at the base of the house because they can be easily laid in strips. The membrane must have the minimum width of the masonry including any plaster. However, it is recommendable to choose the width so that an overlapping connection to the horizontal and, if possible, the vertical surface sealing is feasible as well.
The barrier membrane can be laid as an L or Z barrier in double-shell outer walls. The designations “L barrier" and/or “Z barrier" refer to the shape given to the sealing membrane by the special type of laying in the wall cross-section.
Thanks to the Z barrier, the upper end of the membrane is embedded horizontally in the rear wall shell while the lower end of the membrane is embedded in the front wall shell. This means that the Z lock serves as a cross-sectional seal in both the rear wall and the front wall shell. An L lock is attached to the rear masonry, down the wall and horizontally, if needed with a slight incline to the external part, to the face of the support of the facing wall.
In order to meet the said requirements, the sealing sheets must be particularly flexible and reach a high level of durability. Due to the special material structure, these properties are met by the products DELTA®-SOFTFLEXX, DELTA®-THENE or DELTA®-PVC-MAUERWERKSPERRE when used as an L barrier and DELTA®-PROTEKT when used as an L and Z barrier.