Water infiltration through improperly sealed glass windows and walls can have disastrous consequences for commercial buildings. Choosing the right material to caulk your building’s windows and other glass structures can avoid costly leaks and reduce liability.
Commercial Window Caulking
Caulking is the process of using a waterproof sealant to seal off cracks or gaps around a window. It’s a relatively small investment and a simple job that delivers a big payoff. A high-quality commercial caulking job protects your building for many years against moisture intrusion, drafts, and heat leaks.
Many building owners are unaware that most non-silicone commercial window caulking only lasts 10 years or less. Over time, the caulk hardens and can start to break away from the surface where it’s applied. Moisture may accumulate beneath the loosened caulk and cause damage. Window sealants come in single and multi-component silicones as well as acrylic latex and butyl. We recommend silicone caulking and here’s why.
The Effects of Water Intrusion
Water and moisture intrusion in commercial window systems generally occurs in two places:
- When deterioration of the control-joint sealant occurs (between the window frame and building substrate) and water makes its way inside the window system.
- Age-related and UV-exposure shrinkage of the gasket (between the glass and metal window frames) causes a gap in the building envelope and allows leakage.
Moisture intrusion in commercial structures can cause chronic dampness in spaces like wall voids, service areas, and unventilated attics. The result is usually a hidden mold that will grow unseen until it starts to cause problems, including serious health effects in people.
Silicone Caulking’s Superior Performance
A high-performance sealant, silicone caulking, is far superior to other materials like polyurethane. While urethane and other new hybrid sealants may offer a waterproof solution that lasts up to 10 years, silicone thoroughly waterproofs your building’s window system and consistently has a lifespan of over 20 years. It’s also extremely strong and offers lasting adhesion with significant flexibility.
For any caulking to perform well and function properly, appropriate preparation of window perimeters and glass to metal, aka. wet glazing joints is critical. It’s also important to tool the joints in a concave manner. Many property owners and managers consider this an aesthetic benefit, but few people outside the industry notice or even know what a window perimeter joint is—especially ones that are four floors up or and higher! In all seriousness, the real importance of joint tooling is that it properly beds sealant into the joint and allows it to reach full flexibility and range of motion.
Due to costs and paintability, some building owners or contractors choose to use urethane in window perimeter joints. In our experience, instead of cutting out the old caulking and installing new backer rod and sealant, this material has usually been applied over old, expired caulking. This type of application doesn’t allow for proper flexibility and often leads to window system spot leaks. We typically remove all sealant in a joint and use a grinder on the window’s exterior frame and building substrate to achieve proper adhesion of the new silicone caulking.
In our view, the case for using silicone caulking to waterproof the wet glazing joints in window systems is clear. Our silicone product of choice, Dow Corning 795, offers primerless adhesion and a 20-year warranty. The limited amount of material required in an L-shaped joint, the 4x lifespan vs. urethane caulking, and the time saved in not applying primer are all good reasons for justifying the product’s higher cost.
Choose the Proper and Most Effective Sealant
Watertight windows are one of the tough challenges commercial building owners face. A leak-free structure creates peace of mind and protects a building’s structural integrity. When reviewing proposals for the weatherproofing of your commercial window systems and curtain walls, we believe, despite it’s higher initial cost, silicone is your best choice. It’s important to keep in mind that when you consider labor, access, and insurance costs, the additional up-front expense of silicone is less than 15% of the total waterproofing project cost. Given that the standard warranty for silicone caulking is 20 years—13 to 15 years longer than urethane sealant—the right choice from a long-term cost perspective is obvious.
With years of experience serving commercial clients of all sizes, Presto is the trusted local name in waterproofing. If you’re looking for commercial window caulking services in your city, we’d love to learn more about your project. Contact Presto Restoration for a free consultation today.
Call us at 1-800-785-9927 or email [email protected].