Waterproofing for Concrete Water Tank

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Author Message Randall A Chapple, CSI, CCS, AIA, SE, LEED AP Senior Member Username: rachapple Post Number: 70 Registered: 12-2005 Posted on Wednesday, December 05, 2012 - 12:58 pm:    I have been tasked to develop a waterproofing system for a concrete tank that will be a reservoir for a water feature. I have not done one of these and am interested what any of you have specified in the past. I presume that the waterproofing will be applied to the interior of the tank and may be something like traffic membrane type waterproofing. Thanks for any help Wayne Yancey Senior Member Username: wayne_yancey Post Number: 551 Registered: 01-2008 Posted on Wednesday, December 05, 2012 - 01:09 pm:    Randall, Most recently (2011) for interior concrete reservoirs I specfied a polyurethane membrane from Tnemec. SECTION 071416 – COLD FLUID-APPLIED WATERPROOFING 2. Drawing Designation WPM-3 and 3a: Liquid, cold-applied, pure polyurethane membrane system with tape embedded at changes of plane and points of critical movement. a. Membrane system WPM-3 shall coat entire interior surfaces including wall to ceiling joints and ceilings. b. Membrane system WPM-3a shall coat entire surfaces of structural steel support for prefabricated ladder. 1. Primer: Tnemec Series N69 Hi-Epoxoline ll applied at 4.0 to 6.0 mils dry film thickness. Thin primer 10% to 15% using #4 thinner. 2. Filler and Surfacer: Tnemec Series 215 Surfacing Epoxy mortar to fill and flush transitions rock pockets holes and the like. Plan on using a trowel. a. Color: 1212 Gray. 3. Trowel Grade Mortar Filler: Tnemec Series 265TG, modified polyurethane. 4. First Membrane: Tnemec Series 262 Elasto-Shield applied at 20.0 to 30.0 mils dry film thickness. a. Color: Black. 5. Second Membrane: Tnemec Series 262 Elasto-Shield applied at 20.0 to 30.0 mils dry film thickness. a. Color: Black. 3.4 APPLICATION WPM-3, INTERIOR CONCRETE RESERVOIR – POLYURETHANE MEMBRANE A. Surface Preparation: 1. Step One: Water blast 2500 psi, 6 gpm, 180 degrees, turbo tip with nozzle to within 4 to 6 inches of substrate to remove loose concrete back to a sound substrate and to establish a surface profile. Surface is to be clean, dry and free of contaminants. a. SSPC SP-13 Surface preparation of concrete.. 2. Step Two: Diamond grind to remove loose concrete back to a sound substrate and to establish a surface profile in problem areas. a. Surface is to be clean, dry and free of contaminants. B. Application: 1. Mix, thin and apply materials according to the manufacturer's printed instructions. a. Step One: Apply primer. b. Step Two: Apply filler and surfacer. c. Step Three: Form 1-1/2 inch by 1-1/2 inch cants at changed in plane with trowel grade mortar filler; fill voids and annular rings between changes in materials and penetrations with trowel grade mortar filler. d. Step Four: Apply first membrane with 2-inch wide polyester fabric at transitions and points of potential movement. e. Step Five: Apply second coat of membrane. 2. Allow each coat to dry thoroughly before applying next coat. 3. Provide adequate ventilation for tank interior to carry off solvents during drying phase. 4. Membrane system must be a monolithic pinhole free film. C. Quality control: 1. Membrane system can be non-uniform in color and sheen with streaks, laps, runs and sags. 2. Flood Testing: Pass a 24 hours flood test to a minimum 6 feet elevation above floor. a. If fails: Drain to find breach, repair and repeat test until membrane system passes. 3. Test finished system for holidays per ASTM D4784. 3.5 APPLICATION WPM-3a, INTERIOR STRUCTURAL STEEL IN RESERVOIR – POLYURETHANE MEMBRANE A. Application: 1. Mix, thin and apply materials according to the manufacturer's printed instructions. a. Step One: Apply filler and surfacer over shop primer and field applied grout. b. Step Two: Form 1-1/2 inch by 1-1/2 inch cants at changed in plane with trowel grade mortar filler; fill voids and annular rings between changes in materials and penetrations with trowel grade mortar filler. c. Step Three: Apply second primer membrane with 2-inch wide polyester fabric at transitions and points of potential movement. 2. Allow each coat to dry thoroughly before applying next coat. 3. Provide adequate ventilation for tank interior to carry off solvents during drying phase. 4. Membrane system must be a monolithic pinhole free film. Randall A Chapple, CSI, CCS, AIA, SE, LEED AP Senior Member Username: rachapple Post Number: 71 Registered: 12-2005 Posted on Thursday, December 06, 2012 - 12:28 pm:    Wayne, Thanks