How to Apply Crystalline Waterproofing Material to Basement Walls

Crystalline waterproofing material, or CWM, is a great way to protect your basement walls from water and freezing. This crystalline waterproofing material is applied to basement walls and penetrates into the porous cavities of the cement. This changes the porous concrete into a waterproof solid. This is a great product to use in a wet basement where water seepage is a problem. Installation is straightforward and can be done by any do-it-yourself homeowner.

Step 1: Clean Concrete Wall Surface

The crystalline waterproofing material will only adhere to the concrete surface if it is free from any other obstructions. Use the wire brush to clean off any loose concrete and paint. A hammer and a cold chisel may be needed for large pieces of concrete that must be removed. If there are multiple layers of paint that cover a wide area, try power washing the surface or sandblasting it. 

Step 2: Repair Concrete Surface

If there has been water leaking through the surface of the concrete for any time, you will need to do some repair work before applying the waterproofing material. Use a shop vac to suck up any of the dirt and loose concrete in the cracks or crumbling areas. Mix up some concrete patch, or use some liquid concrete in a tube. Spread it over the surface with a trowel and make sure that the entire crack, or hole, is full of the patch. Let it dry and set before doing anything else to the surface.

Step 3: Wet Surface of Concrete with Water

Before you apply any of the waterproofing material, you will want to wet the concrete thoroughly. You do not want to soak the area, but it should be wet before you apply any of the waterproofing material. 

Step 4: Mix Waterproofing Material

In a bucket, mix the crystalline waterproofing Material with water. Apply just enough water so that the material becomes a thick paste. Do not be alarmed when the material starts to heat up. The chemical process of the water and the material creates this type of chain reaction. 

Step 5: Apply Waterproofing Material to Concrete Wall

Once the material is mixed to a thick paste, apply a thick coating to the concrete wall. Use a masonry brush to spread the waterproofing material over the surface of the wall. It should be thick but should also be even in depth throughout. 

Step 6: Keep Wall Wet While Applying Material

Once the crystalline waterproofing material is applied to the surface of the concrete, you must keep it wet for at least 48 hours. This is so that the materials will penetrate into the porous concrete. If it sets too quickly, it will not have a chance to impregnate the concrete wall. 

Step 7: Sprinkle Over New Concrete Pours

Another way to apply this type of waterproofing material is to sprinkle it over new concrete pours. If you are building a new foundation, then sprinkle the material over the surface of the wet concrete. As the concrete dries, it will cause the material to solidify inside the wall, creating a waterproof seal.