NEXLER BITFLEX System for Foundation Waterproofing

Foundations are the cornerstone of any building, channelling its weight to the ground and ensuring structural integrity. For building longevity, robust protection against moisture and groundwater is absolutely essential. Foundation waterproofing not only prevents material degradation but also safeguards against mold and fungi, which can compromise residents' health. Proper waterproofing is an investment, ensuring the building's durability and future peace of mind for its occupants.

Types of Foundation Waterproofing

Foundation insulation is categorised by its location within the structure: horizontal and vertical waterproofing.

Horizontal Waterproofing

Horizontal waterproofing prevents capillary moisture from rising from the substrate into the wall structure. This is applied at the level of foundation footings and where foundation walls meet above-ground walls. This process is crucial for preventing moisture from penetrating the upper parts of the building, especially when walls are constructed from absorbent materials like brick or aerated concrete.

For robust and safe horizontal foundation waterproofing, using roofing felts specifically designed for underground building sections is recommended. The felt's type and size must correspond to the foundation's width and the prevailing soil and water conditions.

Vertical Waterproofing

Vertical waterproofing shields foundation walls from direct contact with water and ground moisture. It is applied to foundation wall surfaces, forming a barrier against water and moisture ingress from the ground. Effective foundation waterproofing requires not only selecting correct materials but also ensuring their proper connection. Only a tight, continuous barrier can completely protect the building from moisture's and groundwater's detrimental effects. Therefore, a crucial step involves choosing the appropriate waterproofing type, tailored to the ground and water conditions, and the building's structural design.

Choosing the Right Waterproofing

The decision on waterproofing type should stem from analysing ground, water conditions, and the building's structural design. There are two main types of insulation:

Damp-Proof Insulation

This is used when groundwater levels are low (at least 30 cm below foundation, with no periodic fluctuations) and soil exhibits good permeability (e.g., coarse or medium sands). This allows rainwater to drain freely. Damp-proof insulation protects foundations from ground moisture but is insufficient where water is present.

Waterproof insulation

This is necessary when groundwater levels are high or soil is impermeable (e.g., clay), leading to water accumulation near foundations. Waterproof insulation protects foundations from water exerting hydrostatic pressure, ensuring the structure's complete watertightness.

Among various waterproofing products, bituminous water masses are considered the most popular and versatile. Two main types exist:

Thin-layer masses (e.g., Dysperbit type) – used as both primer and waterproofing.
Thick-layer masses (e.g., KMB type) – suitable for any type of waterproofing application.

Before choosing between damp-proof or waterproof insulation, consider a few key questions:

Does groundwater appear continuously or periodically near or above the building foundation?
Are there impermeable soils, such as clays, that could cause temporary water stagnation?
Does the building have a basement?

If the answer to at least one of these is 'yes,' waterproofing is recommended. If the answer to all questions is 'no', you can decide on damp-proof insulation. However, variable ground and water conditions might render the damp-proof insulation insufficient.

Substrate preparation

Before applying a waterproofing coating, you need to thoroughly prepare the substrate. The surface should be clean, free of loose items, dust, and other contaminants that could negatively affect adhesion. Any unevenness and defects in the substrate should be levelled and filled. After thoroughly cleaning the surface, you need to prime it. For this, bituminous water-based primers are recommended, especially those that are deeply penetrating, quick-drying, and based on advanced fine-particle technology.

Key Recommendations for Waterproofing Foundations

Effective protection of foundations against moisture and groundwater requires installing continuous, tight damp-proof or waterproof insulation over the entire surface of the structure in contact with the ground. A waterproofing system works efficiently only if it's used correctly, following the manufacturer's recommendations, meeting technical specifications, and with proper preparation of both the substrate and application conditions. You should pay particular attention to the plinth area because it's also exposed to rainwater. Depending on the chosen solution, the waterproofing should extend at least 30 cm above ground level for a gravel apron, and 50 cm for a concrete apron.

To avoid mechanical damage during backfilling and subsequent construction work, we recommend using protective layers like drainage membranes or dimpled foil.

NEXLER BITFLEX System – a modern waterproofing solution

The NEXLER BITFLEX series features a modern waterproofing system built upon fine-particle anionic emulsion technology. The use of modern materials, including KMB masses from the NEXLER BITFLEX series and quick-drying bituminous-anionic NEXLER BITFLEX Primer, guarantees effective protection even in demanding conditions. Thanks to its fine-particle technology and flexible properties, this system ensures durable insulation and resistance to external factors. Selecting proven solutions and following sound construction practices will enable you to effectively safeguard your foundations and ensure the longevity of your building for many years.

The products in this series are distinguished by:

Exceptional Flexibility: Bridge cracks effectively.
Ease of Application: Apply quickly and efficiently by spray or trowel and simplify the work process.
Radon Barrier: Prevent the carcinogenic gas from entering interior spaces.

Properly executed waterproofing is a long-term investment that safeguards your building from expensive moisture-related damage and structural degradation.