Sunday, September 06, 2020

Concrete Joints and Waterstop

Over its long lifespan, concrete is subject to physical changes in length, width, height, and volume of its mass when subjected to environmental changes and mechanical conditions surrounding it. The effects may be a permanent contraction from drying shrinkage, carbonation, or creep, abnormal changes from chemical reactions of sulfate or alkali attacks, or merely applying a concrete load.

As the concrete moves, it relieves the internal stresses by forming a crack. Engineer designers minimize the unsightly appearance of self-formed cracks by introducing joints into the concrete to accommodate the movement without losing structural integrity. 

Contraction joints divide large pours of concrete into smaller structural units. Contraction joints create a man-made plane of weakness to regulate and control the location of a crack formed by moisture loss of concrete. Without this formed contraction joint, the concrete would freely crack in unexpected and unattractive places.

A scheduled or unscheduled interruption of the concrete pour 30 minutes or greater creates a construction joint.

Designed to negate the compressive forces from abutting concrete structures that may occur due to expansion, loads, or differential movements, expansion joints require an actual gap between the concrete pours, filled with a compressible joint filler material such as foam, rubber, cork, or cane fiberboard.

Waterstop is a preformed joint material, metallic or nonmetallic, designed to stop the migration of fluids by creating an internal dam running across and along concrete joints.

Commercially available waterstops are either metallic or nonmetallic. Metallic waterstops possess high strength and extreme heat and cold resistance but offer little extensibility. Nonmetallic (plastic, rubber) waterstops provide flexibility rather than strength and have good extensibility, recovery, chemical resistance, and fatigue resistance.

Sunday, August 16, 2020

MSI Process for Waterstops

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, 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. Still, even the slightest defect in the waterstop product or its installation can be truly catastrophic to the fluid-tight integrity of the building envelope. For this reason, a great deal of care must go into what I call the MSI Process: Manufacturing, Selection, and Installation.

Waterstop MSI Process

  1. Waterstop MANUFACTURING, history, and types of products commercially available. The manufactured waterstop must be of the highest quality from a manufacturer offering specification, detailing, and installation assistance.
  2. Waterstop product SELECTION is the second most important consideration. Profiles are available for myriad applications and conditions. The designer must choose correctly, preferably with manufacturer consultation.
  3. Waterstop INSTALLATION. Most waterstop failures occur because the material incorrectly installed.

Monday, July 13, 2020

The Little Book of Waterstop Version 2.0

My book, The Little Book of Waterstop Version 2.0 is available for free download here.

The Little Book of Waterstop version 2.0 is the definitive source of waterstop information, including manufacturing, selection, and installation.

Saturday, May 02, 2020

Keyed Waterstop Joints with Keycup and MSB Form

by David R. Poole CSI, ACI

Keycup™ is a multi-function, reusable concrete accessory that securely holds waterstop in place while simultaneously creating a keyed construction joint. Typical applications include:

- Slab on grade
- Wall joints
- Lumber replacement
- Labor saver

MSB Form is an adjustable formwork solution for the concrete construction industry, designed to be compact, lightweight, and strong for all conditions and applications - commercial, industrial, residential, and civil.

When used in conjunction with one another, Keycup and MSB Form are the ultimate labor-saver for keyed concrete slab joints.

Thursday, March 19, 2020

Waterstop with NSF 61 and NSF 372 Certification

J P Specialties, Inc., the manufacturer of Earth Shield® Waterstop, is proud to announce that our PVC waterstops are certified to NSF/ANSI 372 and conforms with the lead content requirements for “lead-free” plumbing as defined by California, Vermont, Maryland, and Louisiana state laws and the U.S. Safe Drinking Water Act.

Additional certifications include:
  • NSF 61 — Safe for drinking water
  • CA Prop 65 — carcinogen-free
  • CRD C-572 — Corps of Engineers specification for waterstop

Qualified technical assistance is available during any phase of your construction project.

Sunday, November 17, 2019

Waterstop Keyway Former — How to Form a Keyed Construction Joint with Waterstop

Four easy steps to form a keyed joint with embedded waterstop.
Keycup™ is a multi-function, reusable concrete accessory that is used to securely hold waterstop in place while simultaneously creating a keyed construction joint. Typical applications include:
  • Slab on grade
  • Wall joints
  • Lumber replacement
  • Labor saver
Keycup1 part number 2" x 120" waterstop keycup
Keycup2 part number 3" x 120" waterstop keycup

For more information visit Keycup.

Patent Pending

Sunday, October 20, 2019

Concrete Contractors — Save Time and Money with the ST-10® Waterstop Splicing Table

The ST-10® Waterstop Splicing Table by J P Specialties, Inc.

The ST-10® was designed and patented by J P Specialties as the perfect solution for producing high-tensile strength, leakproof welds on thermoplastic waterstops such as PVC, HDPE, LDPE, TPER, and TPV. New quality assurance standards in today’s waterstop specifications mandate tensile testing across field welded joints, usually requiring tensile strength 80% or better of the parent material. Waterstops welded with the ST-10® assure the Contractor that their workmanship will yield results conducive to these rigorous requirements. The ST-10® is also an extreme labor saver, taking a two-man job — welding waterstop — and taking it down to just one man.

  • Easy to use
  • Aligns the waterstop
  • Portable, lightweight
  • Weather resistant
  • Minimizes fumes (maximizes safety)
  • High tensile welds
  • Welds under pressure, eliminating air bubbles

Saturday, August 24, 2019

Integrated Expansion Board Cap Waterstop

Integrated expansion board cap waterstop systems are designed to replace post-applied joint sealant, and provide a fluid-tight internal seal like a traditional waterstop with a one-step, integrated unit. Install Earth Shield® expansion board cap waterstop on top of conventional expansion board filler or Earth Shield’s chemical resistant, plastic expansion board. The expansion board acts as the form; therefore, no form splitting is necessary, significantly accelerating the project schedule and provides a long-lasting, attractive finished concrete joint. Earth Shield® screed key cap slides over the top of the metal screed key, eliminating the need for sealant. Like all our thermoplastic vulcanizate waterstops, Earth Shield® integrated cap system waterstop can be heat-welded using a standard waterstop splicing iron allowing for easy field fabrications and allows the waterstop to function as a continuous, homogeneous, fluid-tight diaphragm. Waterstop directional changes are available along with straight roll stock. Custom, fit-to-print waterstop modules are produced to order. Prefabricated ells, tees, tank pads, column fittings, and many others are in stock and ready to ship.