A large portion of my job deals with material testing, building forensics and quality assurance of exterior building applications. In this role I am quite often faced with the responsibility of notifying contractors that their work is unacceptable.

The first question that an architect will have to answer is if waterproofing is required on the building that they are designing.

The initial cost of a roof system is typically 10 percent of the total building cost. However, over the life span the building the roof could account for nearly 60 percent of the building’s total maintenance costs.

Once it has been established that waterproofing is required, the next important decision is to determine where it is required. Typically, waterproofing should be applied over all below-grade concrete surfaces.

To review, there are five reasons why waterproofing is required. They are: 1. To meet code requirements. 2. To keep water out of the building. 3. To protect the structure’s concrete and steel elements. 4. To cope with hydrostatic pressure. 5. To minimize economic concerns, such as the cost of future excavation.

In addition to keeping moisture out of the building, waterproofing serves another equally important role. It helps protect the structural elements - concrete and steel - from damage due to moisture and chemicals in the environment.

The determination of hydrostatic pressure is an important element prior to the design stage. This is a basic factor in the choice of a waterproofing system. By definition, if hydrostatic pressure is present then waterproofing - not dampproofing - is required.

Proper roof specifications require a thorough description of the roof component installation process. Without identification of all component material and installation procedures, the specification is open to contractor interpretation.

The first question that an architect will have to answer is if waterproofing is required on the building that they are designing. This can be a complex question and the answer could have a significant ramification over the life span of the structure.

There is a common misconception that concrete provides waterproofing capabilities. This supposition has led to moisture infiltration and structural damage with countless buildings.