Cementitious Waterproofing in Elevator Pits: A Comprehensive Guide Series

Elevator pits are integral components of modern buildings, often hidden yet crucial for the operation of elevator systems. However, being located below ground level, these pits are inherently prone to water ingress, leading to potential corrosion, structural damage, and operational hazards. They are also quite challenging to access for restoration. In this context, cementitious waterproofing becomes a vital solution.

Cementitious waterproofing, with its robust and reliable nature, stands as an ideal solution for safeguarding these subterranean spaces. This method employs a blend of cement and waterproofing materials to form a hard, durable barrier against moisture penetration. The concrete construction of elevator pits, coupled with the environmental challenges they face, makes cementitious waterproofing particularly effective in protecting these essential spaces.

INTRODUCTION TO CEMENTITIOUS WATERPROOFING SYSTEMS

Cementitious waterproofing systems involve the use of a cement-based solution, often combined with waterproofing additives, to create a moisture-resistant barrier. This method is particularly known for its strong adhesion to concrete surfaces, making it a suitable choice for elevator pits typically constructed with concrete. The mixture, once applied, dries and hardens, forming a dense, durable, and impermeable layer on the surface it’s applied to. These systems are known for their robustness and are particularly suitable for areas subject to high levels of moisture.

ADVANTAGES OF CEMENTITIOUS SYSTEMS

Cementitious waterproofing systems provide a plethora of benefits for construction projects.

• Strong Adhesion: Cementitious materials bond exceptionally well to concrete surfaces, which is a common material in elevator pits.
• Durability: They offer a hard-wearing, abrasion-resistant surface that can withstand tough conditions in subterranean environments.
• Resistance to Positive and Negative Water Pressure: This system is effective in resisting water ingress from both the exterior (positive pressure) and interior (negative pressure) sides.
• Vapor Permeable: Cementitious systems allow trapped moisture within the concrete to escape, preventing issues like vapor buildup.
• 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.
• Compatibility with Concrete: This method is highly effective in elevator pits constructed with concrete, offering a cohesive, integrated waterproofing solution.
• Ease of Application: Cementitious waterproofing can be applied without sophisticated equipment or specialized skills.

CONSIDERATIONS & LIMITATIONS

While cementitious waterproofing offers numerous benefits, it also has its limitations.

• Thickness Control: Achieving and maintaining a consistent thickness across the application area can be challenging with cementitious waterproofing systems.
• Maintenance: The success of cementitious waterproofing hinges on periodic inspection and maintenance to sustain its effectiveness.
• Cure Time: These systems require adequate curing time to develop their full waterproofing properties. This can impact project timelines, as the area may need to remain unused until the curing process is complete. For example, W. R. MEADOWS products require a 48 – 72 hours wet cure, but some other products cure for up to 14 days.
• Environmental Sensitivity: The application and curing process can be affected by weather and temperature, needing careful planning.
• Limited Flexibility: The rigidity of the layer makes it less suitable for structures that undergo significant movement or settling.
• Chemical Sensitivity: Certain cementitious systems may be sensitive to chemicals or pollutants. This is a critical consideration, especially in industrial environments or areas with potential chemical exposure.

WHEN TO CHOOSE A CEMENTITIOUS WATERPROOFING SYSTEM

Choosing cementitious waterproofing over sheet or fluid-applied systems is advisable in scenarios where:

• For elevator pits primarily constructed of concrete, as cementitious systems bond well with this material.
• For areas where there’s a significant risk of water ingress, both from internal and external sources.
• For refurbishing older elevator pits where the original waterproofing needs to be replaced with a similar, compatible material.
• Situations requiring resistance to both inward (positive) and outward (negative) water pressure.

APPLICATION RECOMMENDATIONS FOR MAXIMUM EFFICACY

• Surface Preparation: The concrete surface must be clean, free from oil, grease, or any other contaminants. Any cracks or surface irregularities should be repaired.
• Preparing Mix Design: Follow the manufacturer’s instructions to mix the cementitious waterproofing compound, ensuring a consistent, lump-free consistency.
• Application Process: Apply the mixture using a brush or trowel. It’s often recommended to apply in multiple layers for the best results, allowing each layer to slightly set before applying the next.
• Curing Time: After application, the material needs to cure, creating a solid waterproof barrier. The specific time required for curing varies based on product and environmental conditions.

Cementitious waterproofing is a reliable, durable, and cost-effective choice for elevator pit waterproofing, particularly in concrete structures and high-moisture environments. While it may not offer the flexibility of fluid-applied systems, its strength and compatibility with concrete make it a strong contender for many projects. Understanding the specific needs of your elevator pit and considering factors like structure, environment, and budget will guide you to the most suitable waterproofing solution. Stay tuned for our next article in the series, where we will explore another innovative waterproofing technique.

For expert advice and quality waterproofing solutions, W. R. MEADOWS stands ready to assist in ensuring the longevity and effectiveness of your waterproofing projects.

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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