Thermoplastic waterproofing membrane with active polymer core (APC).

Setting the standard for waterproofing membrane strength, durability and performance for more then 50 years. COREFLEX consists of a thermoplastic membrane integrally bonded to a proprietary Active Polymer Core (APC) layer. Combined with fully welded seams, this provides the ultimate waterproofing protection. Whether your project requires foundation waterproofing, plaza deck restoration, or green roof construction, COREFLEX provides superior waterproofing performance.

The COREFLEX reinforced thermoplastic membrane is engineered to resist high hydrostatic pressure and groundwater contaminants typical of foundation conditions. In addition to waterproofing performance, the membrane has an extremely low water vapor transmission that qualifies it as a Class “A” Vapor Retarder per ASTM E1745.

Dual membrane protection

If COREFLEX’s thermoplastic membrane component is ever punctured or damaged, the superior water barrier performance continues with an APC technology layer that is engineered to actively control water ingress by swelling to produce a reliable seal at the breach. To maximize the performance of the APC Technology, the layer is installed in direct contact with the concrete to be waterproofed, thus preventing water ingress into the structure. With COREFLEX, each membrane overlap seam utilizes both a conventional weld and an overlap assembly of the APC Technology to assure water-tightness. This combination of passive and active barrier technologies provides enhanced seam performance and eliminates the reliance of seam integrity strictly on installation labor.

Exceptional waterproofing performance:

Protection from water Ingress:

  • All seams are heat welded together to form a strong, monolithic waterproofing membrane.
  • Incorporating a high molecular weight plasticizer, the PVC membrane properties will remain intact through the life of the product.

Protection from contaminants:

  • The APC and PVC resists harsh contaminants, including brownfield sites and remedial plaza decks over existing membranes.
  • COREFLEX can solve both water and gas barrier concerns as a Class “A” Vapor Barrier and Certified Methane Barrier (City of Los Angeles).

Installation benefits and features:

Fast and easy:

  • With remedial plaza-deck construction COREFLEX can be installed over most existing membranes, dramatically reducing exposure time of finished space.  
  • No kettles, solvents, fumes or open flames necessary.
  • Faster dry-in time than traditional systems.


  • A true dual-membrane waterproofing system in a single application. The PVC layer of COREFLEX also serves as a root barrier, reducing the number of assembly components for green roof applications.


A polyurethane-based caulk grade swelling paste, AKWASWELL is used primarily to seal rough surfaces in concrete construction joints. Swelling up to 500% of its initial volume when hydrated by water, it creates a positive seal and stops the flow of water through the joint and is suitable for low to moderate hydostatic pressure conditions.

CETSEAL Sealant/Adhesive

A multi-purpose, single component polyether moisture cure sealant/adhesive. CETSEAL is a low VOC, 100% solids, non-shrinking product with excellent UV resistance. Available in 10.1 oz cartridges with 12 cartridges per case at 12 lbs (5.4 kg), or 20 oz foil packs with 12 per case at 20 lbs (9 kg).

CORECAP® Tie-Back Covers

Preformed non-reinforced thermoplastic flashings, designed to provide a welded thermoplastic cover over tie-back heads on property line shoring walls; three preformed sizes available. CoreCap(s) used in conjunction with same size rigid TB-Boot.


A 24 ga. (0.61 mm) stainless steel sheet laminated with a 20 mil (0.50 mm) thick UV stable thermoplastic coating integrally bonded to one side. The thermoplastic coating is compatible with CoreFlex and CoreFlash membranes thus allows for thermoplastic welding to form a monolithic barrier. CoreClad is also resistant to most forms of fungus, algae and micro-biological attack.


A nominal 100 mm (4”) round x 1.5 mm (60 mil) non-reinforced thermoplastic disc. CoreDiscs are used for T-joint patches and to repair small punctures in the PVC membrane.


1.5 mm (60 mil) thick UV stable non-reinforced extruded white thermoplastic membrane used for detail and flashing applications including curbs, walls, field wraps and patches.


1.5 mm (60 mil) thick reinforced thermoplastic membrane (yellow top coat and black bottom coat) used for non-exposed detail and flashing applications including curbs, walls, field wraps, butt-joints and patches.


COREFLEX Consists of a thermoplastic membrane integrally bonded to a self-healing Active Polymer Core (APC). This combination of passive and active barrier technologies, along with fully welded seams, ensures superior waterproofing protection.


Used with COREFLEX XP, CORETEX XP is a polymer impregnated geotextile featuring XP technology for transition details, corners, butt-joints and protection from rough edges and surfaces.


A unique low permeable hydrophilic waterproofing product that utilizes an Active Polymer Core (APC) technology that is less permeable and more chemically resistant than traditional active waterproofing membranes.


Induction Welding Metal Plate with thermoplastic coating.


Molded non-reinforced thermoplastic flashings, specially designed for round penetrations 50 mm (2”) or less in diameter.


A trowel-grade mastic designed for a variety of surface preparation and detailing work with CETCO active waterproofing membranes. Featuring XP Technology hydrophilic polymer, SEAL-X XP swells upon contact with water to form a watertight barrier in fresh to high-saline water conditions. With the consistency of thick grease, SEAL-X XP is easy to apply and bonds to most building materials. Available in 25kg (5 gallon) pails.


A 17-inch wide flexible PVC base-seal profile waterstop used in concrete construction to form a watertight seal across and/or along concrete pour joints. TW-17 can be used in tunnel construction as a grid water barrier.


A weldable thermoplastic rebar support, TW-ANCHOR is a weldable PVC Flange for supporting the dead load of the steel rebar cage concrete reinforcement.


A molded non-reinforced thermoplastic flashings used to seal inside and outside corner details. Universal Corners come as one piece and are trimmed to fit the appropriate corner condition.


An active, flexible strip concrete construction joint waterstop, WATERSTOP-RX provides a strong positive seal by expanding upon contact with water. Proven effective on projects worldwide for over 20 years, Waterstop-RX is designed for both continuous and intermittent hydrostatic conditions. WATERSTOP-RX is available in multiple configurations.

Approval and Certifications

Architectural Specifications

LEED Letter

Product Manuals

Product Sheets

Technical Data Sheets

Helios Energy Research Facility

Berkeley, CA, USA

From design development to construction, CETCO’s expertise in waterproofing was called upon to ensure that the basement, housing expensive laboratory equipment, remains dry at all times. CoreFlex’s composite system also saved the added labor of a two-membrane installation process.

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Mercy Hospital Plaza

St. Louis, MO, USA

To minimize building exposure, poor air quality, and odors, this occupied hospital utilized COREFLEX to waterproof the plaza deck prior to installing a GreenScapes vegetated roof system, hard-scape and water features.

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Piper Tech Parking Deck

Los Angeles, CA, USA

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Ronald McDonald House

Chicago, IL, USA

CETCO provided the complete watertight green roof assembly for the nation’s largest Ronald McDonald House. Protected by CETCO’s COREFLEX® waterproofing membrane, three GreenScapes assemblies—intensive, extensive, and vegetated trays—were utilized to meet a challenging landscape design.

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Rush University Hospital Atrium

Chicago, IL, USA

Rush University is one of the top-ranked nursing colleges in the US. Its hospital is comprised of 676 beds and boasts national rankings in 10 of 16 specialty areas in U.S. New & World Report’s 2011 “America’s Best Hospitals” issue.

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Sandpiper Run Plaza Restoration

Pawley's Island, SC, USA

This restoration application used an extensive GreenScapes system with COREFLEX® waterproofing technology to create an ocean side lawn space for condo occupants. When used in restoration applications, CoreFlex® minimizes demolition, reduces building exposure and limits building down time.

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Shady Hills Gymnasium and Parking Garage

Cambridge, MA, USA

The original spec called for ULTRASEAL below slab with a layer of VOLTEX DS installed over it to provide protection from subsequent concrete operations. However, once the dewatering of the site began, it became apparent that there would be significantly more water at a greater flow rate.

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Toronto Fire Services

Totonto, ON, Canada

Vapor intrusion has become a significant environmental issue for regulators, industry leaders, and concerned residents nationwide. The use of a spray-applied gas vapor barrier to protect against the threat of vapor intrusion has become a widely recognized application by numerous local and state regulatory and guidance groups.

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University of CA Berkeley Boalt Hall

Berkeley, CA USA

University of California Berkeley’s Boalt Hall has an iconic name. A law library set two stories below grade, Simpson Gumpertz & Heger, the waterproofing consultant, had a zero tolerance for water ingress on the new structure.

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Wake Forest University Hosp. Plaza Deck Restoration

Winston-Salem, NC, USA

Restoration of the plaza deck was required for watertightness of the hospital space below and reopening of the emergency room entrance. COREFLEX was quickly installed over the leaking hot-applied rubber membrane to complete the project on time with minimal building exposure.

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