Waterproofing of Drinkable (Potable) Water Treatment Plant Tanks, Reservoirs, Water Channels & Pipes

Cem-Kote systems have over 25 years of field-proven performance

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Gemite’s Cem-Kote Waterproofing Systems withstand Positive and Negative hydrostatic pressure exceeding 5 bar (50 m head of water) and are designed for Internal and External structural waterproofing of concrete and other mineral substrates.

Cem-Kote Cementitious Waterproofing Membranes are suitable for Below and Above grade and are designed to last in different climate zones and conditions and deliver lasting and reliable durability and performance.

Restoration

In restoration projects the concrete surface maybe deteriorated (eroded) to varying depths and requires surface repair.  The condition of the surface is sometimes only found after a suitable surface preparation is carried out, using high-pressure water 35 MPa (5,000 psi), or sandblast – depending on concrete quality and/or contamination.

Levelling & Reprofiling up to 12 mm (1/2”) – Gem-Plast TC
Spray applied and troweled, or hand applied.  Floor slabs may require a higher thickness.

Levelling & Reprofiling over 12 mm (1/2”) – Fibre-Patch OV
For larger volumes consider using Spray-Con WS ST – wet shotcrete process applied mortar.

Rebar Rustproofing – Fibre-Prime
Polymerized cementitious rustproofing is applied to any exposed reinforcing steel

Surface Preparation
Clean the reprofiled surface using 24 MPa (3,500 psi) pressure water to obtain CSP #3 (ICRI International Concrete Repair Institute), before proceeding with application of waterproofing.

Waterproofing & Protection

Design Note:
Product selection is based on existing conditions, or new project requirements

Cem-Kote Flex ST

Flexible Polymerised Cementitious Waterproofing

Cem-Kote Flex ST is a 2-component, flexible, breathable, thixotropic, cementitious modified polymer coating with high adhesion to concrete and properly prepared steel.
Drinking Water Approved – ANSI/NSF Standard 61

Cem-Kote Flex ST is insensitive to moisture in the concrete and high relative humidity unlike polymer coatings.

Cem-Kote Flex ST forms a seamless membrane, without joints, and its inherent flexibility is enhanced with Reinforcing Fabric HD to deliver an excellent bridging of substrate cracks.

Cem-Kote Flex ST forms a highly alkaline coating that protects concrete, or other substrate against attack by salts, and chemicals used in treatment of drinking water.

Application Procedures

  1. Concrete surface is cleaned and profiled using high-pressure water 34 MPa (5,000 psi)
  2. Cracks are repaired using Reinforcing Fabric HD – embedded in Cem-Kote Flex ST
  3. Cem-Kote Flex ST – apply 2-coats by spraying or brushing
  4. Allow 1stcoat of Cem-Kote Flex ST to cure sufficiently to allow application of 2nd
  5. Curing – 3-day air cure is sufficient prior to exposure to water

Cem-Kote CW Plus

Crystalline (in-Depth) Waterproofing

Cem-Kote CW Plus contains reactive chemicals that penetrate the concrete substrate, forming a new, non-soluble crystalline structures that seal capillaries and hairline cracks, making the concrete waterproof.  Drinking Water Approved – ANSI/NSF Standard 61

Cem-Kote CW Plus is breathable, and insensitive to moisture in the concrete and high relative humidity unlike polymer coatings.

Cem-Kote CW Plus advantage over old style crystalline materials is its other Membrane Waterproofing Mechanism that allows direct use on concrete substrates containing cavities, and it also waterproofs concrete substrates “starved” of free calcium ions due to carbonation.

Application Procedures

  1. Concrete surface is cleaned and profiled using high-pressure water 34 MPa (5,000 psi)2
  2. Cracks are repaired using Reinforcing Fabric HD, embedded in Cem-Kote Flex ST
  3. Cem-Kote CW PLUS – apply 2-coats by spraying or brushing
  4. Allow 1stcoat of Cem-Kote CW Plus to cure sufficiently to allow application of 2nd coat
  5. New Concrete – Cem-Kote CW PLUS is broadcast (see TDS for application instructions)
  6. Curing – 3-day moist cure is sufficient prior to exposure to water
Advantages of Cem-Kote Flex over Polymer (epoxy or polyurethane) coatings

New Concrete

Cem-Kote Flex can be applied after curing new concrete for ONLY a few days

Polymer (epoxy or polyurethane) coatings require concrete to be cured for a minimum 28 days (most recommend 45 days) to prevent debonding. Installation of polymer coatings requires frequent testing to satisfy stringent surface “dryness” and very low humidity (35% relative humidity).

Insensitive to Moisture & Humidity

Cem-Kote Flex can be applied on Wet Substrate & at High Humidity

Cem-Kote Flex is completely insensitive to surface moisture and high humidity. It stops water penetration from the Negative side and prevents debonding due to vapor condensation resulting in high capillary pressures at concrete-membrane interface. Polymer coatings are very sensitive to moisture in concrete, surface moisture, high relative humidity and water vapor penetrating from behind or below concrete (below grade).  Most polymer coatings require 1-inch depth of concrete to be dried, or application of moisture barrier layer, prior to application. These procedures are extremely expensive, since drying a concrete tank requires expensive heating for 2 weeks or longer.

Breathability

Cem-Kote Flex is “breathable” = Allows Water Vapor to Escape from inside the Substrate

Polymer membranes act as vapor barriers, preventing water vapor escape - resulting in de-bonding problems.

Flexibility + Crack Bridging

Cem-Kote Flex delivers crack bridging, augmented by Reinforcing Fabric HD

Polymer coatings (epoxy, vinyl-esters or flexibilized epoxies) are non-flexible, without (or limited) crack bridging capability.

Easy + Fast Application

Cem-Kote Flex is Easily & Quickly Applied without Special Equipment

Polymer coatings are “sticky” and the tools and equipment is difficult to clean, even with expensive organic solvents.  Application of polymer coatings has to be carried out in a very narrow “application window”, which increase the applied cost.

Resilient

Cem-Kote Flex is a very “robust” product.

It accommodates large variations in moisture content, relative humidity and temperature, and its “application window” is wide and tolerant to varying site conditions. Application of polymeric coatings is restricted due to the substrate moisture, RH and temperature conditions required. Expensive heating equipment is needed to dry the application area.

Eco-Friendly & Non-Toxic

Cem-Kote Flex is completely Non-Toxic & Not Hazardous

Cem-Kote Flex is a water-based, polymerised cementitious coating and does not require any personal protection.  Only disposable dust masks respirators are recommended during mixing. Polymer coatings are highly flammable, requiring proper ventilation at all times, and emit noxious smell requiring chemical protection (gloves & masks) at all times. Inhalation of epoxy fumes & dust is highly dangerous.

Cost Savings

Cem-Kote Flex is less than 50% of the Applied Cost of polymer coatings

Application of polymer coatings is very complex, especially when moisture and higher humidity exist, which significantly increases application time and results in very high applied cost.

Advantages of Cem-Kote CW Plus over Old-style Crystalline Waterproofing

New Concrete

Cem-Kote CW Plus can be applied next day, after placing concrete

Polymer (epoxy or polyurethane) coatings require concrete to be cured for a minimum 28 days (most recommend 45 days) to prevent debonding. Installation of polymer coatings requires frequent testing to satisfy stringent surface “dryness” and very low humidity (35% relative humidity).

Dual Waterproofing Action

Cem-Kote CW Plus combines Crystalline Waterproofing + Membrane Waterproofing

Result is an extremely Fast Activation - a few days, rather than weeks that are the norm for an old-style crystalline waterproofing. It can be used for negative and positive waterproofing as a brush-or spray-applied slurry.

Quicker Construction

Structures treated with Cem-Kote CW Plus can be filled in less than 24 hours

3-day moisture cure is recommended for Cem-Kote CW Plus, but if needed it can be exposed to water after only an overnight cure, since the membrane mechanism is fast acting. Water Exposure Delay using old-style crystalline waterproofing is several weeks (or longer) since the reaction time of the reactive compounds into concrete is very slow and needs water.

Lack of Free Silicate

Cem-Kote CW Plus Waterproofs Concrete “starved” of free calcium ions

Cem-Kote CW Plus works successfully on concrete substrates “starved” of free calcium ions” due to carbonation provided by Membrane Waterproofing Mechanism. Ordinary (old-style) crystalline waterproofing does not work in some old concrete structures, which due to carbonation have an insufficient amount of free silicate to react.

Poor Concrete

Cem-Kote CW Plus forms a continuous Waterproofing Membrane

Cem-Kote CW Plus positively waterproofs due to its Membrane waterproofing action. Leaks in the structures often occur, because the amount of crystalline material is relatively small, and is insufficient to waterproof spaces (cavities) created by poor concrete consolidation, “sand pockets” in dry shotcrete, insufficient embedment of reinforcing steel, or due to the high porosity of concrete.

Longer Open Time + Easy Application

Cem-Kote CW Plus has a much longer open-time = Easier + Faster Application

Cem-Kote CW Plus is very easy to spray apply using conventional spray equipment, peristaltic or positive displacement, due to its excellent rheology and virtually no rebound. Other crystalline materials have quite short “working time” after mixing, and higher ambient temperatures further shorten set times, resulting in very trying application.

Crack Treatment

Larger cracks are treated using Cem-Kote Flex ST + Reinforcing Fabric HD

Cem-Kote CW Plus system treats any larger substrate cracks using Reinforcing Fabric HD embedded in layer of Cem-Kote Flex ST - cracks are waterproofed quickly (overnight), allowing application of waterproofing system to proceed Old-style crystalline materials can only seal non-moving, hairline cracks, and are unable to seal larger cracks that are moving due to temperature change and structural loading (filling & emptying tanks). The “cut and fill” method used by conventional crystalline supplier is time consuming, costly and takes additional time to develop crystalline action to function properly.

Cost Savings

Cem-Kote CW Plus has lower applied cost than old-style crystalline materials

Ease of application, longer open time and simpler and faster crack treatment of Cem-Kote CW Plus results in lower applied costs.