We've been using the Desertcrete system for more than 3 decades. it's multilayer system provides a long lasting protection needed to prevent water damages on walkable spaces. 

Magnesite is a mineral based cement used mostly for stairs, balcony decks or similar. It looks like chalk in most cases. Magnesite is not completely waterproof, and it might crack eventually allowing water to sip through. 

The Desertcrete system adheres to magnesite supporting its durability when being repaired. However, depending on the conditions it might be best to remove the magnesite material and replace it entirely.