Leaks in the basement can cause damage, but hydraulic cement is a quick solution for sealing cracks and gaps in foundation walls. This fast-setting material expands as it cures, creating a watertight seal even during active leaks. In this video, This Old House host Tom Silva demonstrates how to apply hydraulic cement around a waste pipe in a basement wall.
What is Hydraulic Cement?
Hydraulic cement is a specialized type of cement designed to set and cure in wet conditions. Unlike traditional cement, which requires a dry environment to harden, hydraulic cement can be applied to actively leaking areas, making it a great option for basement waterproofing.
Key Properties of Hydraulic Cement
Hydraulic cement is water-activated, meaning it begins to set when exposed to water, allowing it to cure in damp or wet conditions. As it hardens, hydraulic cement expands slightly, filling in small cracks and creating a tight seal against surrounding surfaces. The formula of this cement causes it to set within minutes of application, speeding up your repairs.
When To Use Hydraulic Cement
Hydraulic cement is useful in many basement waterproofing projects, including sealing cracks in concrete walls or floors, patching holes in pipes, stopping active water leaks, and repairing worn mortar joints in masonry walls. While hydraulic cement can provide a temporary or permanent fix for many basement water issues, you still need to address any underlying causes of leaks.
How To Apply Hydraulic Cement
Applying hydraulic cement requires preparation and quick work because of its rapid setting time.
Preparing the Surface for Hydraulic Cement
Proper surface preparation will guarantee a strong bond between the hydraulic cement and the existing concrete or masonry. Follow these steps to prepare the damaged area:
- Remove loose material: Use a chisel and hammer to chip away any loose concrete or mortar around the leak to provide a stable base for the new cement.
- Clean the surface: Brush away dust and debris with a wire brush to clean the area.
- Create a suitable profile: For smooth surfaces, roughen the area to improve adhesion, giving the new cement something to grip onto.
- Dampen the surface: Moisten the repair area with clean water just before applying the cement to help it set properly.
Applying Hydraulic Cement
Once the area is clean and ready to go, follow these steps for application:
- Prepare the cement: Mix small batches of hydraulic cement according to the manufacturer’s instructions until you get a thick paste.
- Apply the cement: Use a trowel or gloved hands to press the cement firmly into cracks or gaps, making sure it’s well-packed.
- Shape and smooth: Quickly shape the cement and smooth the surface before it begins to set for a clean finish.
- Allow to cure: Keep the repaired area damp for at least 24 hours so it can cure properly.
Tools and Materials Needed to Apply Hydraulic Cement
The right tools are important for the application and safety of this project. To apply hydraulic cement, you’ll need the following tools and materials:
- Hydraulic cement
- Mixing bucket and trowel
- Safety glasses and rubber gloves
- Chisel and hammer (for surface preparation)
- Wire brush
- Clean water for mixing and dampening surfaces
Tips for Working with Hydraulic Cement
To get the best results when using hydraulic cement, mix small amounts of cement that you can use within two to three minutes because of its quick setting time. Always use gloves and safety glasses when handling cement, as it can be hazardous and cause irritation. Mist the repaired area with water periodically for 24 hours after completing your repair for proper curing.
Limitations of Hydraulic Cement
While hydraulic cement is a quick solution for many basement water issues, there are a few limitations. Hydraulic cement can stop leaks, but it doesn’t address underlying damage. For structural cracks or wide gaps, you may want to consult a professional for a proper fix.
Hydraulic cement is also not recommended for expansion joints since they are designed to move and should be sealed with more flexible materials.
Alternative Waterproofing Methods
In some cases, hydraulic cement may not be the best solution for basement waterproofing, especially for larger issues. For that reason, there are a few alternative methods worth considering, such as exterior waterproofing membranes. These are applied to the outside of your foundation, providing a barrier to prevent water from entering your basement.
Interior sealants and coatings seal porous walls and floors from inside your basement. Using epoxy or polyurethane foam can fill cracks and provide a flexible, durable seal. Placing French drains or other drainage systems outside your home can divert water away from your home.
Hydraulic Cement: Our Conclusion
Hydraulic cement is a great tool for addressing basement leaks and water infiltration. However, it’s important to know that it’s just one part of your waterproofing strategy to protect your home’s foundation. For bigger leaks or gaps, consult a professional or consider an alternative method to waterproof your basement.