Product testing according to WTA standard

WTA stands for „Scientific Technical Work Group“. The WTA publishes leaflets in the area of ​​building maintenance and renovation in order to standardize the general quality requirements for waterproofing building materials. These standards are partly covered by national and European standards. In addition to these standards, the WTA regularly tests individual products such as horizontal barriers, renovation plasters and systems for interior waterproofing.

The „Test 4-6“ carried out for us belongs to Unit 4: „Building waterproofing“ and Area 6: „Subsequent sealing of areas in contact with the ground“.

Specifically, in test 4-6, a waterproofing is applied to a standardized test specimen, which is intended to simulate an outer basement wall, for example. This test specimen is then subjected to water pressure over a longer period of time, for example to simulate groundwater. In order to be able to optimally explore the load limit, one works with a total of six test specimens and two load levels:

• 3 specimens, 14 days, 50 cm water column
• 3 specimens, 28 days, 750 cm water column

The water acts exclusively on a free, non-waterproofed area of ​​the test specimen. The evaluation is carried out visually. To pass the test, no water penetration and no blistering or cracking may be observed after the respective test period. Both products have passed the WTA test at the highest load level.

Meaning for KÖSTER WP Mortar
Normal concrete is still water penetrable at a thickness of 5 cm. Conventional barrier mortars have watertight properties from 20 mm. The KÖSTER Barrier Mortar WU to be tested was applied at an average of approximately 4 mm, making the layer comparatively thin.

Even thin layers of KÖSTER WP Mortar increase the waterproofing performance enormously. Continuous layers from 4 mm can be used reliably as interior waterproofing and/or for renovations.

Recommended layer thickness: 4 mm
Endured load: 28 days, 7.5 bar

Meaning for KÖSTER NB 4000
Traditional flexible systems of this type are vulnerable to water hitting the subfloor from the non-waterproofed side. In the event of prolonged exposure, the waterproofing layer detaches from the load-bearing substrate - the waterproofing effect is ruined.

KÖSTER NB 4000 adheres reliably and ensures the waterproofing effect over the long term. After sealing the pores with KÖSTER WP Mortar, apply it in two thin layers. It should be noted here that the first layer must set sufficiently so that it can no longer be damaged when the next layer is applied.

Recommended layer thickness: 3 mm
Endured load: 28 days, 7.5 bar




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