You have just purchased Poly Lock to mechanically fasten an HDPE geomembrane to a concrete structure. It is the professional solution for critical transitions between plastic sheeting and civil works: perimeter walls of a landfill, pond walls, inspection chambers, or geomembrane anchorages on concrete-headed slopes. In this guide, we will show you how to install it correctly to ensure a durable seal.
Product specifications
Poly Lock is a polyethylene profile with a T-shaped or trapezoidal section designed to be embedded in concrete during pouring or anchored to hardened concrete. The protruding flap receives the geomembrane, which is mechanically trapped between the profile and a counter-flap secured with a screw. The seal is watertight and resists both hydrostatic pressure and differential movements between the membrane and the concrete.
| Specification | Poly Lock |
|---|---|
| Material | Polyethylene (PE) |
| Fastening type | Mechanical with screw |
| Application | Geomembrane – concrete seal |
| Compatibility | HDPE geomembrane and similar |
| Service life | Permanent (non-biodegradable) |
Step-by-step usage guide
Poly Lock supports two installation methods: embedded during fresh concrete pouring or mechanically anchored to hardened concrete. Embedded installation is more watertight and professional but requires planning with the civil works. Anchored to dry concrete is viable when the wall is already built.
Mark the fastening line
Use chalk to mark the horizontal line where the Poly Lock profile will run. This is usually 10 to 15 cm (4 to 6 in) above the anticipated maximum liquid level. This elevation defines how high the geomembrane extends before transitioning to the concrete.
Prepare the base profile
If embedding the profile in fresh concrete, attach the Poly Lock to the inner formwork of the wall before pouring, using small nails or double-sided tape. Ensure the flange faces the geomembrane side. If anchoring to hardened concrete, mark and drill fastening points every 30 cm (12 in).
Pour concrete or anchor to the wall
For embedded installation, pour concrete into the wall and allow it to set; when the formwork is removed, the profile is integrated into the wall with the flange protruding. For anchored installation, secure the profile with stainless steel screws and expansion anchors to the pre-drilled points, with a butyl sealant joint between the profile and the concrete.
Unroll the geomembrane up to the profile
Bring the edge of the geomembrane up to completely cover the Poly Lock flange, leaving a 5 cm (2 in) margin above. The geomembrane must lie flat on the flange, without folds or wrinkles, in full contact with the profile surface.
Weld the geomembrane to the profile
Use an extrusion welding machine with an HDPE welding rod to fuse the edge of the geomembrane against the Poly Lock flange. Material compatibility (both polyethylene) ensures molecular fusion. Inspect the weld bead for any points without penetration.
Seal the top joint
Apply polyurethane sealant to the upper edge where the geomembrane joins the concrete above the profile. This band prevents surface water from entering behind the Poly Lock and compromising the fastening over time.
Whenever civil works allow, plan for embedded installation instead of anchoring to hardened concrete. Embedded installation requires no additional screws, anchors, or sealants: the profile is integrated into the wall itself, and the fastening is permanent. The aesthetic and durability difference is significant, especially in audited hydraulic works.
Do not fasten the geomembrane to the concrete directly with screws, without Poly Lock. Each screw perforates the geomembrane and becomes a leak point, no matter how many washers and sealant are used. Poly Lock exists precisely so that mechanical fastening never pierces the impermeable sheet: screws secure the profile to the concrete, and the geomembrane is sealed against the profile by welding.
Embedded or anchored Poly Lock?
If you're unsure whether to choose embedded or anchored installation for an existing wall, or need to calculate linear meters of Poly Lock for your project's perimeter, ask the virtual assistant. It will guide you based on the type of civil work and project phase.
Complementary products
Poly Lock does not work in isolation: it requires a geomembrane, extrusion welding, and a compatible rod. These three complementary products are what you will need for any hydraulic work involving a geomembrane-to-concrete transition.
HDPE polyethylene geomembrane is the waterproofing sheet that Poly Lock fastens to concrete: both materials are compatible for extrusion welding. The extrusion welding machine is the indispensable tool for fusing the bead between the geomembrane and the profile; without it, the mechanical seal is not watertight. HDPE welding rod (bead) is the consumable that melts during the operation; calculate the quantity by linear meters according to the machine manufacturer's specifications.
Maintenance and care
Properly installed Poly Lock is permanent and requires no maintenance. Periodic inspection focuses on verifying that the seal shows no signs of failure:
- Annual visual inspection: check the profile and weld bead for cracks, detachments, or the presence of moisture behind the Poly Lock. Any visible leak must be addressed before it progresses.
- No subsequent mechanical aggression: the profile protrudes from the concrete and may be hit by equipment during maintenance of the work. Signal it or protect it with a metal stop when possible.
- Top sealant review: the polyurethane caulk on the top edge degrades before the rest of the system. Reapply every 5 to 7 years to maintain the complete barrier.
- Storage of uninstalled profiles: in a covered place, on a flat surface, without heavy objects on top that could deform the flange.
Frequently asked questions
Can I use Poly Lock to fix PVC geomembrane or only HDPE?
Polyethylene Poly Lock is compatible with HDPE and LLDPE geomembranes: both are polyethylenes and are welded together by molecular fusion. For PVC or EPDM, the fastening is not by welding but by mechanical compression with a counter-flange and rubber gasket; specific versions exist for these cases. Before purchasing, verify material compatibility with the virtual assistant.
Is it essential to install Poly Lock in waterproofing works with geomembrane?
Yes, in any transition between geomembrane and concrete structure. It is the critical point of the entire work: if the transition fails, it does not matter if the geomembrane is perfect, there is a leak. In audited projects (landfills, industrial ponds, treatment plants), the audit requires the Poly Lock system or a certified equivalent.
Embedded in fresh concrete or anchored to hardened wall, which to choose?
Embedded whenever civil works allow it: more watertight, without screws that create potential leak points and at an equal or lower material cost. Anchored to hardened concrete is reserved for existing works where the wall is already built, or for repairs. Embedding is planned in advance: it is necessary to coordinate with the formwork crew and the pouring moment.