WATERPROOFING - Completing the Envelope.

Once the sources of water have been identified, the types of systems to prevent leakage chosen, and the materials selected to provide necessary aesthetics to the finished product, the envelope design must be carefully constructed and reviewed to ensure successful performance of the completed product. To prevent all possible water intrusion causes, a building must be enveloped from top to bottom with barrier or drainage systems, with divertor com- ponents added where appropriate to increase performance of the envelope.

These systems then must interact integrally to prevent water infiltration. Should any one of these systems fail or not act integrally with all other envelope components, leakage will occur.

Even with continuing technological advances in building materials, water continues to create unnecessary problems in completed construction products. This is most often due to an envelope’s inability to act as an integrated system that prevents water and pollutant infiltration. All too often several systems are designed into a building that have been chosen inde- pendently and are acting independently rather than cohesively.

Detailing transitions from one component to another or terminations into structural com- ponents are often overlooked. Product substitutions that do not act integrally with other specified systems create problems and leakage. Inadequate attention to movement characteristic of a structure can cause stress to in-place systems that they are not able to withstand. All these situations acting separately or in combination will eventually cause water intrusion.