Check of layer thickness and thorough drying of waterproofing products

The respect of layer thickness is one of the main issues when waterproofing basement walls with polymer-modified bitumen thick coatings (PMBC) or flexible cement-based flexible slurries (MDS) for obtaining a reliable and sustainable watertight performance. For this reason, great importance is attached to the minimal layer thickness in the regulations/standards for waterproofing (in Germany DIN 18533, PMBC or MDS guideline). When using trowel-, brush- or spray-grade waterproofing materials, the total application thickness must be controlled to ensure the functionality of the waterproofing. Since the drying of the materials is also influenced by the layer thickness, this must be checked before the excavation is filled with earth.

Waterproofing

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Minimal dry layer thicknesses

1. The necessary dry layer thickness of all the above-mentioned categories of waterproofing materials depends upon water load and material type: either polymer-modified bitumen thick coatings or crack-bridging/non-crack-bridging cement-based waterproofing slurries (MDS).
2. Control of layer thickness with a layer thickness gauge (weber Schichtdickenmesser).
3. The insertion of the woven glass fiber mesh weber.sys 981 makes visible if the layer thickness is sufficient.
4. The layer thickness control with the notched trowel weber.sys Schichtdickenkelle is also possible. Whatever the hand angle is, the layer thickness remains unchanged (3 mm). Here with the 2-comp. lightweight bitumen waterproofing thick coating weber.tec Superflex 10.
5. This special notched trowel allows better layer thickness control also for the 2-comp. reactive and quick-setting waterproofing coating weber.tec Superflex D 24.
6. Smoothing of the second layer weber.tec Superflex D 24 (applied with the above-mentioned notched trowel) with flat trowel.
7. Whenever cement-based flexible waterproofing coatings are applied with a flat trowel, for ex. weber.tec Superflex D 2, their uniform layer thickness can be checked very well with a notched trowel. Here is the application with the flat trowel weber.sys Aufstreichkelle + triangular notched blade Zahnleiste no. 2 (notch size 5 mm).
8. Smoothing of the second layer weber.tec Superflex D 2 with a flat trowel.
9. The complete drying is checked on a sample stone, which is deposited near the building to be water-proofed. The best practice is to lay different layer thicknesses on the sample stone at the beginning of waterproofing works.
10. After completion of waterproofing works, the drying of the whole layer surface is checked by cutting the bitumen layers applied on the sample stone. The bitumen is completely dry when it is black and does not stick to fingers.
11. Only after complete drying of the waterproofing layers, insulation boards can be applied to the last waterproofing layer.