Once the prep is completed, it is imperative the concrete substrate is clean and dry as per the manufacturer’s specified requirements to facilitate a good adhesive chemical bond. Proper application in terms of thickness and coverage of all waterproofing components including primer, base coat, and topcoat will impact the bond. Curing is also an important factor that should not be overlooked as inter-coat adhesion can also be affected if one of the components does not fully cure.
The performance of the waterproofing system during its entire useful service life will be dependant on factors such as design, workmanship, assessment, maintenance, and repairs. Upon closer examination of these factors, one gains a deeper understanding of how the integrity of the waterproofing is undermined and how the structural components are affected.
Design
The design methodology has a significant impact on the overall outcome of the waterproofing performance beyond adhering to minimum code requirements. Here are some common questions to consider during th
e preliminary design stage:
• Does the below grade surrounding area have a high-water table or is the area prone to flooding?
• Are the materials selected durable and suitable for the specific application?
• Are there penetrations and sections of the expansion joint directly above critical infrastructure?
• Do the floor slabs and foundation walls have enough provisions for drainage?
Without considering these types of questions, the designer can create vulnerabilities once the project is initiated. Locations and detailing of expansion joints and other types of penetrations such as drains is critical since these areas are the most susceptible to failure of the waterproofing systems. During many garage condition assessments completed, one will commonly observe concrete ledge beams supporting the intermediate slab experiencing delaminated concrete due to premature failure of the expansion joint waterproofing. Delaminated concrete can develop as early as five to 10 years following a breach in the water barrier. As the structural elements age and the waterproofing membrane approaches its end of useful service life, the concrete deterioration can be quite significant if the structural elements were exposed to consistent water and foreign contaminant ingress over extended periods of time.
