Property managers and owners often ask: “If I have my building façade ‘sealed’ will that prevent it from leaking?” This question often signals misconceptions regarding the expectations of applying a “sealer”, or as is correctly called a water repellent.
Although there can be benefits from using water repellents, these materials are not intended to provide complete “waterproof” protection. They should be applied after first understanding their purpose and conducting any necessary façade repairs prior to application.
The types of repairs are numerous and can include:
- Repointing cracked and damaged mortar joints
- Replacing joint sealants (caulking)
- Replacing or repairing cracked façade materials (brick, stone, precast concrete, stucco, etc.),
- Installing missing/failed flashing systems and damaged exterior envelope components
Before any repairs are undertaken, it is recommended that existing conditions be thoroughly
reviewed and discussed with a qualified building envelope contractor and/or consultant. It is critical to determine the causes, and not just the symptoms, of moisture infiltration. Frequently water intrusion problems are due to issues behind the surface within the back-up walls, roofs, or the foundation.
A key to understanding water repellents is they do not “bridge” or fill cracks, holes, or other voids. These issues and associated repairs must first be addressed prior to water repellent application for the best results. Also, it is vital to use a water repellent that allows building exterior substrates to breathe. While it is important to keep moisture out of a façade, it is just as essential to allow moisture from within to escape.
Once an appropriate water repellent material is selected and properly applied to a clean and restored façade, there are a number of benefits that can be realized.
- Clear penetrating repellents reduce the rate of water absorption into the building’s exterior components. This allows for the extended protection of these building materials.
- By preventing water from sitting in voids and cracks behind the surface, the risk of freeze-thaw damage (water allowed to sit beneath the surface, freeze in the winter, and expand when thawing, leading to face spalling and cracking) is reduced.
- Proper application of a water repellent can increase the duration required between façade cleaning or power washing.
The benefits and cost savings from using a systematic approach to building façade repairs and application of water repellents are substantial. As a building manager, understanding the limitations of water repellents, and regularly maintaining façade components, will greatly increase the life of the structure, and save long term capital repairs costs for your owners.
