About the Flat Ribbed Profile
Flat ribbed waterstops are specified for non-moving construction joints in concrete structures — joints where continuous bonded reinforcement carries through the joint and the waterstop is exposed to negligible or no movement. Without a centerbulb or tear web, the profile lies flat across the joint, with a series of ribs running along each flange to create mechanical interlock with the surrounding concrete. The result is a continuous diaphragm intended to prevent the passage of liquid through the joint, with sealing characteristics that are widely regarded as the best of any flat profile.
Flat ribbed profiles are produced in widths of 4 inches, 6 inches, and 9 inches across a range of weights and head pressure ratings, with the appropriate size depending on the project’s hydrostatic head pressure, concrete thickness, and specification. Some profiles in this family are tied to specific engineering firm standards such as MWH Black & Veatch. See the sizing reference below or reach out for help selecting a profile for your specification.
Typical Applications
✓Commonly Specified For
- Non-moving construction joints
- Joints with continuous reinforcement through the joint
- Water and wastewater treatment plants
- Reservoirs, aqueducts, and lock-and-dam systems
- Tunnels, culverts, and foundation walls
- Containment structures and tanks
- Potable water contact applications
- MWH Black & Veatch and similar engineering firm specifications
→Other Profiles May Be Considered When
- The joint will experience movement — see Ribbed Centerbulb or Dumbbell with Centerbulb
- Large joint movements are expected — see Tear Web profiles
- A dumbbell-anchored non-moving profile is preferred — see Dumbbell
- The application is a slab-on-grade joint — see Base Seal
- The joint is at an existing concrete face — see Retrofit profiles
Profile selection should always be verified against project specifications and engineering requirements. Contact us if you’d like assistance reviewing options for your application.
Available Sizes & Versions
Sika Greenstreak produces flat ribbed waterstop in a range of profile sizes to suit different joint widths, concrete thicknesses, and head pressure ratings.
Profile 646
Width: 9″
Thickness: 3/8″ rib / 1/8″ web
Weight: 2.37 lb/ft
Head Pressure: 175 ft (523 kPa)
Profile 679
Width: 6″
Thickness: 3/8″ rib / 1/8″ web
Weight: 1.50 lb/ft
Head Pressure: 125 ft (373 kPa)
Profile 781
Width: 4″
Thickness: 3/16″ rib / 1/8″ web
Weight: 0.43 lb/ft
Head Pressure: 65 ft (194 kPa)
Profile 782
Width: 6″
Thickness: 7/16″ rib / 3/16″ web
Weight: 0.84 lb/ft
Head Pressure: 75 ft (224 kPa)
Profile 783
Width: 6″
Thickness: 3/8″ rib / 1/4″ web
Weight: 1.39 lb/ft
Head Pressure: 125 ft (373 kPa)
Profile 786
Width: 9″
Thickness: 3/8″ rib / 1/4″ web
Weight: 2.07 lb/ft
Head Pressure: 175 ft (523 kPa)
Sizing considerations generally include hydrostatic head, concrete cover, and any engineering-firm-specific specifications. Contact us if you’d like help cross-referencing a profile against your spec.
Installation Overview
Flat ribbed waterstops are typically installed prior to concrete placement using split formwork. Heat welding is generally the recognized method for splicing PVC waterstop, and factory-fabricated transitions are widely recommended to reduce the risk of failure at intersections. Always refer to the manufacturer’s installation guide and project specifications for complete instructions.
Center the waterstop over the joint with roughly half the profile projecting into each pour.
Tie off the outer flange to adjacent reinforcing steel using hog rings, punched flanges, or similar methods.
Heat-weld butt splices in the field. Factory fabrications are generally recommended for changes of direction.
Place and consolidate concrete around both flanges to encapsulate the waterstop fully.
Frequently Asked Questions
+What is a non-moving joint, and why use a flat ribbed profile there?
A non-moving joint is a construction joint where 100% of the bonded steel reinforcement runs continuously through the joint, exposing the waterstop to negligible or no movement. Because there’s no expected flex, a centerbulb or tear web isn’t needed — the joint won’t open enough to require one. Flat ribbed profiles are preferred for these applications because the ribbed flange geometry provides the best sealing characteristics of any non-moving profile, creating strong mechanical interlock between the PVC and the surrounding concrete.
+How is a flat ribbed profile different from a dumbbell?
Both profiles are suitable for non-moving joints, but they anchor into the concrete differently. Flat ribbed profiles use a series of ribs along the flange to create mechanical interlock and are generally noted for providing the best sealing characteristics of any non-moving profile. Dumbbell profiles rely on enlarged bulb-shaped ends at the edges of the flanges to anchor the waterstop. Sika literature recommends ribbed shapes over dumbbell shapes when better sealing is the priority.
+Which flat ribbed profile should I specify?
Selection typically comes down to width, hydrostatic head requirements, and any engineering firm specifications on the project. The 781 (4″) and 782 (6″) are lighter profiles for lower head pressure applications. The 783 (6″) and 786 (9″) are heavier-duty profiles with thicker webs for higher head pressure. The 646 (9″) and 679 (6″) are specifically tied to MWH Black & Veatch standards. If your specification calls out a profile by number, that’s the deciding factor — otherwise, project-specific requirements should drive the final selection.
+What if my joint actually does move?
Flat ribbed profiles are not appropriate for movement joints. Without a centerbulb or tear web to absorb joint flex, a flat profile placed in a moving joint can go into tension and fail. If the joint is designed to accommodate drying shrinkage, thermal expansion, settlement, or live load deflections, a movement-joint profile such as Ribbed Centerbulb, Dumbbell with Centerbulb, or Tear Web should be specified instead.
+Are factory-fabricated intersections necessary, or can they be done in the field?
Field-fabricated intersections are widely cited as a leading cause of waterstop performance issues. Sika recommends factory-made fabrications for L’s, T’s, crosses, and other changes of direction. Field welding is generally appropriate for straight butt splices between runs of waterstop. The project specification will typically indicate which approach is required.
+Are flat ribbed profiles suitable for potable water structures?
All Sika Greenstreak PVC waterstop profiles, including each flat ribbed size, are NSF/ANSI 61 certified for potable water contact. This makes them appropriate for many applications such as finished water reservoirs and treatment plant clearwells, subject to project-specific requirements.
+How is flat ribbed waterstop welded in the field?
PVC waterstop is typically heat-welded using a thermostatically controlled splicing iron. The two ends are squared, butted against the heated blade until the PVC begins to melt, then pressed together and held until cool. Sika offers a Waterstop Welding Certification Program for contractors seeking formal training, as weld quality has a significant impact on long-term performance.
