Sheet-Applied Waterproofing in Elevator Pits: A Comprehensive Guide Series

When it comes to constructing waterproof systems, the choice of material and application methodology can greatly influence the longevity and overall performance of the structure being worked on. This is even more important when tackling an elevator pit. Due to access, function, location, and the fact that elevator pits tend to be the lowest points in a building, they are especially susceptible to water intrusion and other costly scenarios that are hard to retroactively fix, not to mention the scheduling nightmare that can come from needing to make a repair. Therefore, it is critical to make sure you plan ahead and create a reliable and secure waterproofing system from the beginning.

At W. R. MEADOWS, we have consistently been proponents of superior technology and products that ensure maximum protection and structural integrity. This is why we wanted to take the time to delve into the intricacies of using sheet-applied waterproofing systems for elevator pits.

INTRODUCTION TO SHEET-APPLIED WATERPROOFING SYSTEMS

Sheet-applied waterproofing systems employ pre-fabricated membrane sheets, which are designed to adhere securely to the substrate, forming a robust barrier against moisture and water ingress. However, keep in mind that different products offer different types of bonds. For example, most products created for blindside applications offer either a mechanical or a chemical bond. Check the manufacturer label of the product you are choosing to find out if the type of bond is right for your project.

The adhesion process, which is crucial, involves carefully laying the sheets over the prepared surface and ensuring they are seamlessly bonded, either through self-adhesive properties, heat welding, or with the aid of specific adhesives. This creates a continuous, impermeable layer that conforms closely to the surface contours, even in areas with complex shapes.

The quick application of these sheets is another significant advantage. Unlike other methods that may require multiple layers or extensive curing time, sheet-applied systems can be rolled out and secured relatively quickly, significantly reducing downtime in construction or maintenance projects. This efficiency does not compromise the quality of the waterproofing, as these sheets are designed for long-term durability and resistance to environmental stressors.

ADVANTAGES OF SHEET-APPLIED SYSTEMS

Sheet-applied waterproofing systems offer a range of advantages for new construction projects, particularly in the context of elevator pits.

• Durability & Longevity: Sheet-applied waterproofing systems are very durable and strong. Not to mention, with appropriate installation and maintenance, sheet-applied systems can dramatically extend the lifespan of the structure.
• Strong Mechanical Bonding: In regards to blindside application, this waterproofing system integrates seamlessly with the concrete, creating a strong mechanical bond. This bond plays a crucial role in ensuring waterproofing efficacy and can accommodate movement, adding to its structural integrity.
• Warranties: While not all manufacturers offer them, warranties provide financial and performance protection. Some may have associated costs, so check with your product’s manufacturer for details.

CONSIDERATIONS & LIMITATIONS

While sheet-applied waterproofing systems abound in benefits, they’re not without limitations:

• Surface Preparation: The substrate must be smooth, sound, and clean to ensure proper adhesion with sheet-applied waterproofing membranes. Irregularities can compromise your waterproofing system membrane’s effectiveness.
• Application Conditions: Extreme temperature and humidity, as well as specific climates, can affect the installation process and potential performance of the system depending on product/system used. Adverse conditions may lead to poor sealing or longer curing times.
• Accessibility: Sheet-applied systems require physical access to the entire pit for proper installation, which may be challenging in restricted spaces or renovations.
• Seam Integrity: Overlaps and seams demand precise workmanship; any gaps can become points of potential failure.
• Repair Difficulty: Post-installation repairs can be more complex and costly compared to fluid-applied and cementitious systems, as accessing the damaged area may be difficult.
• Risk Factors: Some may bypass the full “bathtub” method (only waterproofing the four walls and skipping the ground foundation) owing to budgetary and scheduling concerns. Yet, eschewing this method might spell unforeseen complications later on. Employing vapor barriers is pivotal if not adopting the full bathtub approach. However, the complete ‘bathtub’ technique is highly endorsed for its lucrative ROI in terms of extended lifespan and reduced maintenance expenses.

WHEN TO CHOOSE SHEET-APPLIED WATERPROOFING SYSTEM

When choosing which type of waterproofing system is right for your project, consider two things. One, is this new construction or it repair/rejuvenation; and two, consider what type of access you have. Opt for a sheet-applied waterproofing system in the following scenarios:

1. New construction with access to the exterior of the wall.
2. New construction, when needing to do a blindside application.
3. When substrate is harsh and the waterproofing system needs to be very durable.
4. Repair project where the concrete has aged enough to require pouring fresh concrete to an area using the blindside application method.

APPLICATION RECOMMENDATIONS FOR MAXIMUM EFFICACY

1. Follow Instructions: Adhere strictly to the manufacturer’s instructions as each system and product has its own nuances. This is so important to ensure the waterproofing system performs as intended and so to protect any warranties that are considered or provided.
2. Champion the Excavation: Commence by shaping the pit ready for waterproofing. Despite potential cost savings, the return on investment for the full bathtub application is worth it. A comprehensive approach minimizes future risks and maximizes performance.
3. Deploy Membranes: Maintain continuity of the waterproofing membrane to prevent any breaches that could lead to leaks. Make sure you are overlapping and merging membranes correctly.
4. Prioritize Thoroughness: Pay meticulous attention to how you are applying and setting up your waterproofing system. Your waterproofing barrier’s strength is based on the products used and proper application. Make a mistake in application and your systems barrier loses strength and continuity.
5. Detailing: Pay careful attention to detailing, especially around corners and edges, which are critical to the integrity of the waterproofing system. Anything that goes through the membrane needs to be thoroughly detailed.
6. Fastening Points: Securely fasten all points and detail sufficiently as recommended by the manufacturer to avoid any dislodgment or water ingress.
7. Overlap/End laps: Ensure proper overlap and end laps between sheets, as these are key to creating a seamless and impervious barrier.

Sheet-applied waterproofing systems stand out for their undeniable advantages, especially when it comes to new construction and, notably, elevator pits. Prioritizing a robust mechanical bond combined with a comprehensive “bathtub” application ensures that the waterproofing method remains steadfast and trustworthy for years to come.

Whether you’re a constructor, a distributor, or venturing into the specialized domain of elevator pit waterproofing, it’s essential to emphasize meticulous planning, preparation, precise application, consistent maintenance and routine scheduled checks, and a commitment to not cut any corners. These steps ensure that the system remains impervious and long-lasting.

At W. R. MEADOWS, our credo is clear: Quality and diligence in waterproofing equate to a long-term investment in safety and structural integrity. Never compromise on the method or material. Choose solutions built for endurance. Should you need expert guidance or products tailored to your requirements, our team is here to assist. Always remember: a well-protected foundation is the bedrock of a lasting structure.

If you have any questions about waterproofing elevator pits, please contact Christian Warren, United States based, at cwarren@wrmeadows.com or Gary Tench, Canadian based, at gmtench@wrmeadows.com. Alternatively, you can call (800) 342-5976.

To find out more about W. R. MEADOWS building envelope solutions, including our various waterproofing systems, please click here.

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