Sika Sika Greenstreak Lockstop

Sika Greenstreak Lockstop is a strip-applied mastic waterstop specifically engineered for nonmoving concrete joint waterproofing. Installed using Lockstop Primer Adhesive, it creates a durable, watertight seal between concrete surfaces without swelling or generating internal joint pressure — making it a low-risk, high-performance alternative to hydrophilic waterstop systems. Its slim, pliable profile requires minimal concrete cover, simplifying forming requirements and reducing material costs on tight-clearance applications.

Lockstop’s flexible mastic composition conforms closely to the concrete substrate, filling minor surface irregularities and exhibiting self-healing characteristics that help maintain long-term waterproof integrity. Designed to perform across a broad range of temperatures and weather conditions, Lockstop keeps projects on schedule regardless of site conditions — a critical advantage for contractors working in variable climates or year-round construction environments.

Key Features

Lockstop is a non-expansive mastic waterstop purpose-built for static, nonmoving construction joints. When paired with Lockstop Primer Adhesive, it forms a continuous, watertight seal that holds up under long-term hydrostatic exposure without swelling or placing stress on the surrounding concrete.

Its self-healing, pliable composition is one of Lockstop’s most valuable field advantages — the material conforms naturally to uneven or imperfect concrete surfaces, compensating for minor surface irregularities that could compromise other waterstop systems. Because it is non-expansive, Lockstop can be positioned outside of the reinforcing steel with minimal concrete cover, offering greater flexibility in joint design and reducing formwork complexity.

Installation is straightforward in nearly any site condition. Lockstop performs across a wide range of temperatures and weather environments, minimizing weather-related delays. Splicing is handled with simple lap joints, and corners and intersections can be molded by hand or bent to shape — eliminating the need for heat welding equipment required by PVC waterstop systems.

Lockstop also delivers solid chemical resistance, showing no visible deterioration when exposed to common 5% chemical solutions including KOH, HCl, H₂SO₄, NaOH, and H₂S — making it a dependable choice for wastewater, industrial, and containment structure applications.

Technical Specifications

Frequently Asked Questions

How is Lockstop installed? Begin by brush-applying a 2-inch wide coat of Lockstop Primer Adhesive along the joint surface. Allow the primer to dry for approximately two hours before placing the waterstop — both the primer and waterstop should be applied the same day. Once the primer is ready, press Lockstop firmly and continuously into the primed area, achieving roughly 25% lateral spread across the material’s width. The concrete surface should be smooth, dry, and free of laitance or oil, and concrete should be allowed to cure a minimum of 24 hours before application.

Can Lockstop be mechanically fastened? Yes. For vertical or overhead applications where additional holding power is needed, concrete nails may be used at approximately 12 inches on center. Mechanical fastening should always be used in addition to — not as a replacement for — the Lockstop Primer Adhesive.

How are splices and corners handled? Splices are made by lapping the ends of the material side-by-side approximately 1 inch and molding them together until no gaps or air pockets remain. The same molding technique applies at intersections and corners. Alternatively, Lockstop can simply be bent around corners to avoid splicing altogether, saving time on complex joint layouts.

When should the separation paper be removed? Do not remove the separation paper until just prior to the second concrete pour. Before placement, inspect the full length of the strip for any discontinuities or debris contamination. If damage is found, remove and replace the affected section with new material rather than attempting a repair.

Does Lockstop swell like hydrophilic waterstops? No. Unlike hydrophilic or swelling waterstop products, Lockstop is entirely non-expansive. It will not absorb moisture or generate internal joint pressure, which means it can be safely positioned outside the reinforcing steel with minimal concrete cover — a significant advantage in tighter joint configurations or where rebar spacing is limited.

What types of joints is Lockstop suitable for? Lockstop is designed specifically for nonmoving, static construction joints. Common applications include retaining walls, box culverts, concrete pipe joints, vaults, slabs, elevator shafts, and penetrations. For joints that require movement accommodation, a PVC centerbulb or retrofit waterstop system would be more appropriate.

What is the shelf life and how should Lockstop be stored? Lockstop has a shelf life of two years when stored properly. Keep it in a cool, dark, dry environment in a tightly closed container to maintain product integrity until installation.

Is Lockstop chemically resistant? Yes. Lockstop demonstrates no visible deterioration when exposed to 5% solutions of common industrial chemicals including KOH, HCl, H₂SO₄, NaOH, and H₂S, making it well-suited for wastewater treatment facilities, containment structures, and other chemically demanding environments.