Application Guide for Crystalline Waterproofing Products

This method statement outlines the procedures for the specification and application of a crystalline waterproofing system to concrete structures. The objective is to ensure the concrete is rendered impermeable to water, thereby enhancing its durability and longevity.

1. Scope of Work

The scope includes surface preparation, application of the crystalline waterproofing product, curing, and quality assurance. This method applies to both new and existing concrete structures.

2. Materials and Tools

Materials:

• Crystalline Waterproofing Product: (e.g., Vandex, Batimix etc…)

• Clean Water: For mixing crystalline products.

• Cementitious Repair Mortar: For repairing defects such as honeycombs, voids, and cracks.

• Patching and Plugging Materials:

  • Hydraulic Cement: For rapid-setting repairs, especially for active leaks.\
  • Epoxy Mortar: For structural repairs and bonding.
  • Polyurethane Grout: For injection into cracks and joints to stop leaks.
  • Fiber-reinforced Mortar: For areas requiring enhanced tensile strength.

Tools:

• Clean containers for mixing
• Brushes or brooms for application
• Trowels and spatulas
• Water sprayers
• Mixing drill with appropriate paddles
• Caulking gun for grout application
• Injection equipment for polyurethane grout
• Protective gear (gloves, masks, safety glasses)

3. Weather Conditions for Application

1. Temperature:

• Ideal ambient temperature range: 5°C to 35°C (41°F to 95°F).
• Do not apply if the temperature is expected to fall below 5°C (41°F) within 48 hours after application.
• Avoid application during extreme heat (above 35°C or 95°F). If unavoidable, work during cooler parts of the day and keep the concrete surface damp.

2. Humidity:

• High humidity conditions (above 85%) are favorable as they aid in the curing process. However, ensure there is no standing water on the surface.

3. Wind:

• Avoid application during high wind conditions which can cause rapid evaporation of water from the slurry, leading to improper curing.

4. Precipitation:

• Do not apply during rain or if rain is forecasted within 24 hours of application.
• Protect the surface from rain, frost, and direct sunlight during the curing period.

4. Surface Preparation

• Completion of Substrate Preparations:

  • Ensure that all pipe sleeves, vents, curbs, inserts, drains, and other projections through the substrate to be waterproofed have been completed prior to starting waterproofing work.

• Inspection and Repair:

  • Inspect the substrate for defects such as honeycombs, voids, and cracks.
  • Repair any defects using suitable cementitious repair mortar to provide a sound substrate.
  • Remove all forming materials, including reveal inserts.

• Cleaning:

  • Remove all dirt, oil, grease, laitance, and other contaminants from the concrete surface using a wire brush, water jetting, or sandblasting.
  • Ensure the surface is free from standing water, but damp.

• Protection of Other Work:

  • Protect other work from damage caused by cleaning, preparation, and application of waterproofing.
  • Provide temporary enclosures to confine spraying operations and to ensure adequate ambient temperatures and ventilation conditions for application.

• Patching and Plugging:

  • Do not allow waterproofing, patching, and plugging materials to enter reveals or annular spaces intended for resilient sealants or gaskets, such as joint spaces between pipes and pipe sleeves.
  • Stop active water leaks with plugging compound.
  • Repair damaged or unsatisfactory substrate with patching compound.
  • At holes and cracks 1/16 inch (1.6 mm) wide or larger in substrate, remove loosened chips and cut reveal with sides perpendicular to surface, not tapered, and minimum 1 inch (25 mm) deep. Fill reveal with patching compound flush with surface.

• Surface Preparation for Optimal Bonding:

  • Remove efflorescence, chalk, dust, dirt, mortar spatter, grease, oils, paint, curing compounds, and form-release agents to ensure that waterproofing bonds to surfaces.
  • Provide concrete surface profile in accordance with the manufacturer’s written instructions.
  • Clean concrete surfaces in accordance with ASTM D4258:
  • Scratch- and Float-Finished Concrete: Etch with a 10 percent muriatic acid solution in accordance with ASTM D4260.
  • Smooth-Formed and Trowel-Finished Concrete: Prepare by mechanical abrading or abrasive-blast cleaning in accordance with ASTM D4259.
  • Clean concrete unit masonry surfaces in accordance with ASTM D4261:
  • Lightweight Concrete Unit Masonry: Etch with a 10 percent muriatic acid solution or abrade surface by wire brushing. Remove acid residue until pH readings of water after rinse are not more than 1.0 pH lower or 2.0 pH higher than pH of water before rinse.
  • Medium- and Normal-Weight Concrete Unit Masonry: Sandblast or bushhammer to a depth of 1/16 inch (1.6 mm).
  • Concrete Joints: Clean reveals.

5. Mixing

• Mixing Ratios:

  • Follow Holderchem’s specifications for mixing the crystalline waterproofing powder with water. Typically, a slurry mix is prepared at a ratio of 5 parts powder to 2 parts water by volume.

• Mixing Procedure:

  • Gradually add the crystalline waterproofing powder to the measured water while continuously stirring to avoid lumps.
  • Mix thoroughly until a homogenous, creamy consistency is achieved.

6. Application

1. Surface Preparation Prior to Application:

• Saturate the surface with water for several hours and maintain a damp condition until applying waterproofing. Remove standing water.

2. First Coat:

• Apply the first coat of the slurry mix uniformly using a stiff brush or broom.
• Ensure complete coverage of the surface without leaving any gaps.

3. Second Coat:

• After the first coat has reached an initial set (typically within 2-4 hours, but not fully cured), apply the second coat perpendicular to the first coat to ensure thorough coverage.
• Maintain the surface damp between coats.

4. Dry Shake Method (Alternative for horizontal surfaces):

• For freshly poured concrete, broadcast the crystalline powder evenly at the specified rate immediately after initial set.
• Trowel the powder into the surface to ensure full integration.

5. Application to Specific Areas:

• Apply waterproofing to surfaces, and extend waterproofing onto adjacent surfaces as follows:

  • Onto columns integral with treated walls.
  • Onto interior nontreated walls intersecting exterior treated walls, for a distance of 24 inches (600 mm) for cast-in-place concrete and 48 inches (1200 mm) for masonry.
  • Onto exterior walls and onto both exterior and interior columns, for a height of 12 inches (300 mm), where floors, but not walls, are treated.
  • Onto every substrate in areas indicated for treatment, including pipe trenches, pipe chases, pits, sumps, and similar offsets and features.

6. Initial Coat Application:

• Apply the initial coat by brush, hand trowel, or spray equipment in accordance with the waterproofing manufacturer’s written instructions. Immediately follow up the spray application of the initial coat with brushing to ensure the coat fills voids and is in full contact with the substrate with each final brush stroke in the same direction.

7. Number of Coats:

• Apply the number of coats required for the specified water permeability, typically two or three.

8. Subsequent Coats:

• For multiple coats, apply subsequent coats while the previous coat is still “green” and can support the additional coating being applied. When brush applied, place final applied brush strokes perpendicular to brush strokes of the previous coat.
• Dampen the surface between coats.

9. Final Coat Finish:

• Provide a smooth, brushed, or spray-textured final coat finish. When brush applied, place final applied brush strokes in the same direction to provide an even texture and finish.

7. Curing and Protection

1. Moist Curing:

• Moist-cure waterproofing for a minimum number of days in accordance with the manufacturer’s written instructions, immediately after the final coat has set, followed by air drying, unless otherwise recommended in writing by the manufacturer.

2. Timing of Backfilling or Filling Water Containment Structures:

• Complete backfilling or filling water containment structures treated with waterproofing in accordance with the manufacturer’s written instructions.

3. Protection Courses:

• Provide protection courses when backfilling to protect treated surfaces from gouging, scratching, and other damage.

8. Field Quality Control

1. Manufacturer’s Field Service:

• Engage a factory-authorized service representative to test and inspect the completed application of waterproofing.

2. Testing and Inspection Reports:

• Prepare test and inspection reports documenting the quality and effectiveness of the waterproofing application.

9. Conclusion

By adhering to this method statement, the application of crystalline waterproofing products will be carried out effectively, ensuring the concrete structure is properly protected against water ingress. Proper execution, weather condition consideration, and quality control are critical to the success of the waterproofing system.