concrete and masonry accessories
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Mastic & Hydrophilic Waterstops

Synko-Flex® 302Fuel Resistant
Synko-Flex® 312
Hydro-Flex® 302Primer 311



Installation and
Technical Data

Synko-Flex® 302 mastic waterstops

Synko-Flex       Preformed Plastic Adhesive Waterstop

Synko-Flex® .. NSF 61 Certified Waterstops

Henry Synko-Flex Synko-Flex® 302 waterstop is a non-expansive, single component, self-sealing plastic adhesive compound, extruded in a square cross-sections between two quick release protective wrappers. It bonds to cured concrete surfaces and fuses with fresh concrete during the hydration and curing process to achieve a watertight seal. Once adhered, Synko-Flex is unaffected by rain, snow or infiltrating ground water which may be present during the installation period. Click here to see documentation (PDF) of NSF Certified Waterstops.


SYNKO-FLEX’s unique formula and packaging provides a simple, easy-to-install solution for effective waterstop sealing. It is also resistant to acids, alkalis and hydrogen sulfide gases over the life of the structure. SYNKO-FLEX has been used since 1968 as a waterstop Mastic Waterstops Packaging for cold joints in highway tunnels, airport terminals, marine animals theme parks, hospitals, performing art theaters, parking garages, hotels, office buildings, fish hatcheries, enclosed potable water reservoirs, warehouses sports complexes and wastewater plants.

Synko-Flex® 302 waterstop is a specially formulated preformed adhesive joint sealant that provides a lasting, watertight bond to both fresh and cured concrete surfaces. Designed as an alternative to conventional waterstops that are used in cold joints at footings, walls or slab joints.

Synko-Flex® Primer

The primer readily penetrates the pores and seals dusty concrete surfaces to providing an optimal surface for the adhesion and bonding of Synko-Flex performed mastic waterstops.