What are Mastic Waterstops?

Commercially available mastic waterstops are sold in rolls or strips. The profile is usually a small rectangle or trapezoidal shape, with 3/4”  x 1” being somewhat of a standard. These strips are adhered to existing concrete using an adhesive or primer, or alternately concrete nails at 12” on-center spacing. This adhesion is important, as only three sides of the waterstop will then be exposed to fresh concrete. If the waterstop is displaced during the concrete pour it can easily lose most if not all of its effectiveness. Also, like their similar hydrophilic cousin, mastic waterstops are designed for non-moving construction joints only. No expansion, isolation, or contraction joints.

Unlike the hydrophilic waterstops, mastic waterstops are simply a strip of tacky, rubbery compound (usually based on bitumen and butyl rubber) that is designed to “stick” to a primed surface of a cured concrete cold joint on one side, and have fresh concrete cast against the remaining three sides, with the heat from the hydrating concrete causing the product to become even tackier, and therefore sealing the joint by acting as an internal, adhered sealant.

Adeka P-201 — A Real Waterstop Problem Solver

• Urethane rubber – hydrophilic agent urethane polymer
• Good chemical resistance and durability  pH range 3~11
• Easy to use ONE part hydrophilic urethane (cartridge or pail)
• Easy to apply
• Temperature / humidity cure
• Excellent adhesive strength
• Excellent Durability
• Expansion approximately 2Xs by volume

Adeka P-201 is a single component, hydrophilic, modified urethane waterstop that comes in a 10.8 ounce cartridge. P-201 is used as a waterstop in new construction and in repair applications. It can be placed on damp or uneven surfaces and functions in a wide range of temperatures and ground water conditions.

P-201 will expand up to 2 times (100%) by volume in the presence of water. It will expand in the direction of least resistance. When expansion is inhibited, the product will produce expansion pressure against the resisting substance. This expansion pressure will effectively seal off water penetration. The amount of concrete coverage required depends on bead size. The coverage may range from 2” (1⁄4” bead) to 4” inside a double mat of rebar (1⁄2” bead). Bead size also determines hydrostatic head resistance.

Adeka P-201 cartridge

J P Specialties, Inc. is proud to stock and sell P-201 waterstop sealant.

Expansion Board Cap Waterstop — A Short On-Line Introductory Presentation

We have just posted a short introduction to our integrated cap system, waterstop profiles (JPEB350, JPEB375, et al). Additional information is available from our Technical Sales staff. Expansion board cap waterstop profiles are designed to be installed over the expansion joint filler board, negating the need for form-splitting and post-applied sealant, while simultaneously providing a fluid-tight waterstop seal embedded in the concrete. Click here for an introduction.