Basement waterproofing from the inside: crystalline waterproofing

Ground moisture seeping into the basement is a common problem in both old and new buildings, especially when water rises through the floor, the surroundings are already finished and the foundation can no longer be dug out. In that case you need waterproofing from the inside that not only holds back water but also protects the concrete itself.

Why crystalline waterproofing fits here

Surface waterproofing coatings are also suitable for basements, but when water presses from the other side of the wall (negative pressure) not all of them work from the inside: you need coatings rated for negative pressure, such as PLASTIVO 180 or VANDEX BB 75. Crystalline waterproofing works differently – it crystallises inside the concrete itself, so it does not depend on bonding to the surface and also protects the concrete. A simple, reliable solution is the deep crystalline waterproofing VANDEX SUPER.

How crystalline waterproofing works

Once applied to the concrete surface, the active chemicals react with free lime and moisture in the capillaries and form insoluble crystalline structures. The crystals block capillaries and micro-cracks, so water, even under pressure, can no longer get through. Vapour can still migrate, so the concrete stays "breathing".

Because water does not get in, the reinforcement is also protected from corrosion. VANDEX SUPER also protects concrete from sea water, sewage, aggressive groundwater and chemical solutions. As the crystals densify the concrete structure, there is a side benefit: higher compressive strength.

When to work

It is best to waterproof in autumn or spring, when the groundwater level is high:

• defects and strong leaks that need repair are easiest to see;
• the concrete is already wet and needs no extra moistening. VANDEX penetrates the concrete only with water and does not react in dry concrete, so in summer dry concrete would have to be soaked thoroughly.

Step by step

1. Prepare the surface. The key condition is clean, damp concrete. Remove paint, plaster and other surface layers.
2. Repair. Fill cracks and joints with the repair mortar VANDEX CEMLINE MG 4 or VANDEX UNI MORTAR 1 and stop water leaks with the rapid-setting VANDEX PLUG.
3. Apply. Brush VANDEX SUPER onto the repaired, damp, clean surface. The chemical reaction starts.
4. Cure for 5 days. Protect the surface so the crystals are not wiped or washed off, and keep it moist with a fine water mist so it does not dry out.
5. Finish. The waterproofing slowly continues deeper into the concrete. After a few weeks the surface layer can be cleaned off, because the whole effect stays inside the concrete.

As the effect is deep inside, the treated surface can be drilled or nailed if needed without damaging the waterproofing.

Where else it works

VANDEX SUPER is used not only for basements but wherever there is concrete: foundations, wells, lift shafts, drinking water and wastewater tanks, dams, quays and bridges. It is certified for contact with drinking water.