How a bottom plate can be sealed

Normally, the gravel or gravel layer under the poured concrete floor slab provides adequate seal against rising moisture from the groundwater in the ground. If a capillary-breaking layer is present, the seal above the bottom plate can be diffusion-tight. If the layer is not present, the concrete must be able to "breathe" upwards and therefore be provided with sealing material which has a capillary effect and is permeable to diffusion.

Sealing with existing capillary-breaking layer

Normally, a thermal insulation is applied to the gravel or ballast layer by means of foil or mats. These additionally seal off and ensure the breathability of the concrete at the same time. Several materials are suitable for sealing on the base plate. Bitumen membranes hermetically seal the base plate and substructure if properly welded. As further materials, the construction industry standard DIN DIN 18195-4 also mentions asphalt mastic, geomembranes made of plastics such as elastomer and bitumen thick coatings. Very important in the sealing are the transitions of the floor slab edges to masonry. At these critical points, the risk of forming moisture bridges is high.

Waterproofing with breathability and diffusibility

For the sealing of the bottom plate, which gives off moisture and must dry out regularly, permeable materials are necessary. Commercially multi-layered mineral mud is offered for this purpose. An alternative is the Dielung represents, the laying of unpainted wood, where only a little "working" hardwood must be used. Other products that are suitable for sealing are granules that are applied to the floor slab under the subsequent screed. As niche products ecologically oriented sealing materials are available, which however must be checked before use to see whether they meet the legal requirements. Examples are loam and clay granules or plates or even specially mixed types of cement and mortar containing, for example, cereals.

How a bottom plate can be sealed: sealed

The external conditions play an important role

In order to achieve a reliable and durable sealing of a floor slab, the local circumstances must be checked carefully. Weather pages, soil conditions, slopes and space utilization above the base plate influence the best possible selection. Even within the legal framework, the procedures and choice of materials are often a matter of faith. Since the stability and habitability of the whole building depends on the successful sealing of a floor slab supporting a residential building, several opinions should be obtained and compared.

Video Board: Sealing and Insulating the Rim Joist