Waterproofing is an absolute necessity for an earth-sheltered building, where inadequate waterproofing can range from a nuisance to a disaster. The designer, contractor, owner and lender demand watertightness for the life of the structure. Which waterproofing? I'd suggest you start with the following parameters: What materials are being used to build the structure poured concrete, precast concrete or concrete block? What is the nature of the soil sand, clay or rock? What are the water conditions? Is the water table above or below the floor slab level? Who will be applying the waterproofing the owner, the contractor or a waterproofing subcontractor? When each of these factors is known you can immediately rule out some products, leaving fewer choices from which to make the final selection. Every waterproofing system has certain limitations and, if these limitations are ignored, the likelihood of a poor job will be increased. You must examine waterproofing materials by the criteria that are established by your structure and your construction procedures.
The generic names for the common types of waterproofing materials are bentonite, composite sheet membranes, synthetic rubber sheet membranes, liquid applied membranes, and cementitious coatings. This article discusses each of these types of materials.
Cementitious coatings are, as the name implies, based on Portland cement. These coatings are easy to apply and relatively low in cost. Essentially they will provide a very dense, durable coating of cement paste or mortar to the existing concrete surface. A disadvantage of the system: It is incapable of bridging moving cracks. It will move with the concrete it is bonded to and crack with it. However, given the right structure, cementitious coatings can provide very effective waterproofing.