Showing posts with label waterstop. Show all posts
Showing posts with label waterstop. Show all posts

Friday, January 01, 2021

Sunday, September 16, 2018

Understanding Waterstop

To understand what a waterstop is, it is helpful to understand what it is not. Waterstop will not prevent the migration of moisture through a concrete slab, protecting the installed flooring system (such as tile or hardwood) from adhesion failure or deterioration. Nor will waterstop have any effect on capillary water migration through concrete walls. Vapor barriers, drain boards, concrete admixtures, bituminous wraps, flashings, and multiple other construction products are available to the specifier, contractor, or end-user for these criteria and there are many good books written on the subject.

PVC Waterstop
Waterstop has a singular purpose: To prevent the passage of fluids across and along concrete joints. Waterstop does all of its work at the joint. Because concrete joints are frequently open and subject to hydrostatic loads, a strong case states that waterstop has the most critical role in fluid-proofing a concrete structure. A pinhole or imperfection in a vapor barrier will have little to no noticeable effect, but even the slightest defect in a waterstop product or its installation can be truly catastrophic to the fluid-tight integrity of the building envelope. 

The first waterstops used in construction were strips of lead or copper. In the early 1900s, the preferred waterstop material shifted to vulcanized rubbers such as neoprene or styrene butadiene rubber (SBR). While rubber waterstops had excellent mechanical properties (high tensile strength and elongation) they had one major weakness: they were challenging to fabricate as the rubber was vulcanized, meaning it had already taken a “set” (thermoset) and could not be heat welded together like the metals used previously.

In 1926, Waldo Semon of the B. F. Goodrich Company invented plasticized PVC. Semon was attempting to dehydrohalogenate (non-plasticized) PVC in a solution of boiling solvent to create an unsaturated polymer that would be useful for bonding rubber to metal. The results of Semon’s experiment was the creation of a thermoplastic with properties very similar to rubber.  

It took many years for plasticized PVC to find suitable commercial applications, and was first used as a waterstop material in the early 1950s. Back then, the material was properly labeled as fPVC or flexible PVC. The first wide-scale test of any waterstop was performed in 1954 by the Hydro-Electric Power Commission of Ontario, Canada. Many manufacturers still use the results of this test as a benchmark, and other than some new polymers, waterstop has not changed that much since then.


Saturday, December 09, 2017

Hydrophobic Waterstop for Concrete Joints

When most engineers or contractors think of a “waterstop” what they’re generally referring to is a 50-foot long section of a flexible, water-proof material (usually plastic or rubber), six to nine inches wide, and installed along the concrete joint in between the formwork. This waterstop is more accurately defined as a hydrophobic waterstop: A waterstop designed to prevent the passage of fluids by repelling them along and away from the waterstop product, and creating an internal dam at and along the concrete joint. Hydrophobicity is the amount of water repulsion of the surface of the waterstop, and can actually be measured: Place a drop of water on the flat side of the waterstop to be tested and measure the relief angle of the water drop. The sharper the angle the more hydrophobic the waterstop material is. An angle 90 degrees or greater makes the waterstop truly hydrophobic and this product will actively move fluids along the joint and away from the source.
A waterstop that will perform well must have adequate strength and extensibility to avoid be torn or ruptured by joint movement. The best waterstop products are able to maintain these properties (high tensile strength, good elongation [ASTM D-412]) when exposed to the installed environment for the service life of the structure. Exposure conditions which could affect a waterstop’s service life are:


  1. Temperature
  2. UV exposure
  3. Ozone exposure
  4. Chemical attack


Hydrophobic TPV Waterstop by Earth Shield
Because hydrophobic waterstops act as dams at the concrete joint, a general rule of thumb is the greater the size of a waterstop (waterstop size is actually it’s width, e.g. 4”, 6”, 9”, etc.), the greater the head pressure the waterstop will resist. A small 4” waterstop is more than suitable for a containment wall surrounding a tank farm, or even a swimming pool in a back yard, but would be completely inappropriate for the foot of a large dam. Giant concrete structures such as dams or locks will require 9” wide waterstops or greater.

It’s not just width (size) that effects waterstop performance, thickness also plays an important role. Just like conventional dams, the thicker waterstops are able to resist higher head pressures of water (or other aqueous fluids).

Because proper installation plays such a critical part in the effectiveness of a given waterstop system, the very best waterstops are those that can be fused and fabricated easily. For this reason, the majority of today’s design engineers specify and require thermoplastic waterstops (such as PVC or #waterstop), and not the earlier thermoset varieties (neoprene, SBR, natural rubber). Thermoplastic materials have the ability to be easily field fabricated for simple change of directions and the joining of straight lengths; whereas, the earlier thermoset rubber materials generally were ineffectively glued and clamped together causing a severe weakness in the waterstop diaphragm and leaking.

A waterstop’s cross-sectional area is called its profile, and there are lots of profiles to choose from, but really they all share the same basic anatomy: a series of fins or bulbs to provide interlock with the concrete, the body or web to provide the necessary rigidity and product width, and possibly a hollow cavity or bulb to enable the waterstop with additional movement properties.

By far, the largest difference between various waterstops on the market today are the polymers they are constructed of, and the services offered by various manufacturer’s. It is up to the individual designer to find a manufacturer that offers the desired set of services and support for their project. These after-sale services and support are truly what separates a great manufactured waterstop from a poor one. Just remember, “Choose wisely.” A waterstop is permanently installed in concrete (much like rebar) and there really are no second chances to get it right.

Monday, November 28, 2016

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.

Friday, November 11, 2016

Earth Shield High Density Polyethylene Waterstop

From the leading producer of waterstop products used in the concrete construction industry, J P Specialties, Inc. now add to their range of high-caliber Earth Shield products with the introduction of a material specifically designed to contain oils, fuel and other hydrocarbon products.

The Earth Shield HDPE (High Density Polyethylene) waterstop will create an impenetrable seal for aggressive non polar fluids without suffering any physical decay or distortion to the integrity of its structure over long periods of time, making it the ideal choice for storing hot petroleum oils, industrial solvents and aromatic compounds such as benzene or gasoline products.



This premium thermoplastic copolymer also has the added advantage of being a deliberately engineered, non-toxic plastic which is free of Bisphenol-A and its much publicized detrimental health effects.  This also means that it will not bleed potentially hazardous chemicals such as plasticizers, fillers and stabilizers into the surrounding environment when put into contact with petrochemicals.

Earth Shield HDPE waterstop is ideal for creating an effective chemical barrier in large tanks and holding areas of industrial scale facilities and with its inert behavior and unrivaled qualities in storing hydrocarbon products safely, securely and effectively.


As an established pioneer in the waterstop industry, J P Specialties, Inc. can not only provide high-tech, modern solutions for industrial needs with their range of waterstop products, but they also supply expert technical assistance for both the planning and the design stages of a project, complete with 2D and 3D modeling and both product and project certifications to guarantee the suitability of the product within the overall design.

Wednesday, October 12, 2016

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.

Sunday, October 02, 2016

Mastic Waterstops

Most 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 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.



Obviously, this waterstop function is very limited as the only barrier to migrating fluids is the adhesion to the concrete and compression of the mastic waterstop product within the joint. For this reason, mastic waterstops tend to be more effective in construction situations where large concrete loads are applied on top of the waterstop such as wall on footing or burial vault lid, and far less effective when installed in vertical applications such as a wall joint.

Mastic waterstops are the lowest performing of any commercially available waterstop and are price accordingly, being the lowest cost waterstop as well. Because of the low cost and ease of installation, mastic waterstops are the favored products of commercial constructors and home builders.


Excerpt From: David Poole. “The Little Book of Waterstop.” Waterstop King, 2013. iBooks. https://itun.es/us/Ngg6J.l

Tuesday, December 09, 2008

New Retrofit Waterstop Profile Accommodates Very Large Joint Movements



JP Specialties, Inc. has developed a new Earth Shield® waterstop product specifically designed to accommodate large shear movements, such as tank ring foundations subjected to settlement. The JP621L Retrofit Waterstop System is chemically and mechanically adhered to the existing concrete using one of our chemical resistant, novolac epoxies (VEN500 or VEN1000), stainless steel batten bar, and stainless steel anchor bolts. The waterstop profile is combed along the fastening leg, which facilitates the epoxy bonding to the profile. The embedded waterstop leg has two large polymer dams which are designed to create a torturous fluid path and simultaneously perform as anchor points for the new concrete to bond to. The JP621L profile has a large, tear-web centerbulb that can move greater than five inches without deformation of the waterstops main body. (The thin diaphragm, or "tear-web", ruptures under shear stress, allowing the "U-bulb" to move freely for its entire length when installed in an open joint.) JP621L Retrofit Waterstop can be heat welded to a continuous, fluid-tight barrier, like all our Earth Shield® waterstop profiles, and can be joined to our baseseal (or rearguard) profiles for intersecting joints.