Surfaces should be level and free of all sharp rocks (all rock and stone greater than .05 diameter), objects, vegetation and stubble. (Soil sterilization may be necessary to kill roots and certain types of grasses.)

The subgrade surface should provide a unyielding foundation for the geomembrane with no sharp or abrupt changes or break in grade. Proper compaction assures stability and support of the liner.

No

Yes

Rough ground and standing water, mud, snow - any excessive moisture - is counterproductive for liner deployment.

Groundwater should be taken into account and, if present, it will need to be controlled both during and after construction. One method for controlling groundwater is to develop a French drain system under the lining that allows the water to flow laterally under the lining without floating the lining.

A good design for an underdrain is to pipe it to the outside of the lake into a gravel sump. This allows the sump to run continuously during construction and, with the placement of an upright at this sump, the underdrain can be pumped if needed to relieve hydrostatic pressure and gas buildup under the lining system.

Side slopes should be no steeper than 3:1 whenever feasible. Contact CLI directly when site specifications or conditions differ.

Slopes are usually hand-raked to achieve proper smoothness.

The pallets are shipped rolled with a tarp cover to prevent damage, and to protect the tightly folded and rolled material from direct sunlight and heat.

Each pallet may weigh up to 5,000 lbs. and the rolls can be unloaded and transported by field fork equipment of sufficient capacity.

Liner panels are fabricated into large sheets to minimize field seaming. These large panels are first accordian folded, then rolled up on a core and strapped to a wooden pallet.

The adhesives, solvents, shrouds and other items are generally shipped with the panels. It is recommended that the liners panels' protective covering not be removed until installation and that any uncovered panels be stored out of direct sunlight.

To secure the edges of the lining in an earthen pit, an "anchor trench" is dug. Anchor trenches are approx. two foot wide by two foot deep (2' x 2') and one foot back from the crest of the berm (standard trench dimensions and depth vary according to project design.)

Dirt removed should be raked out flat on the far side of the trench, away from the pit, to be used to backfill after the liner edges are laid out in the anchor trench, while allowing the panels to be unrolled along the berm.

Slightly rounding corners of the trench avoids sharp bends in the geomembrane. The trench itself needs to be free of loose soil and rocks.

Use a lift system that suspends a roll off the ground. The roll is raised by a loader, forklift, crane or other lifting equipment and then spooled off and deployed. An unwind stand can also be used from a modified flatbed trailer.

It takes considerable manpower to deploy a liner. It is "pulled" but not stretched. Minor wrinkles insure the liner is installed in a relaxed condition.

A ballast system, such as dead weights (sand bags) and anchor trenches are used for all geomembranes installed in exposed applications. For buried applications, the installed liner should be temporarily secured by sand bags until cover soils are placed, working from center to out.

Take time when unloading and placing rolls of lining to avoid damage. Verify the location of a panel or sheet before unrolling and placement to avoid improper alignment.

Sandbags (or similar ballast) are required to keep the panels in place during installation, exposed or covered - a minimum of 25 bags per panel.

If is it windy: wind uplift and wind suction forces can lift exposed, unballasted liners off the ground and potentially damage them.

Care should be taken to avoid wrinkles in the seam areas and around mechanical attachments.

Pre-fabricating panels at our facility into essentially larger panels reduces the amount of field seaming a project requires. (Fabrication seaming is performed under controlled conditions and the seams are fully tested.)

The lining material itself determines the types of field seaming techniques used.

The most commonly used process is solvent welding, which is very similar to welding pipe and basically melts the adjacent panels together. Wedge welding provides excellent seam properties and reproducible welds and is faster and cleaner than solvents.

Now, with advanced technology in field welding, the use of wedge welders that apply heat and pressure to form a homogenous weld are becoming the state-of-the-art.

Place the geomembrane over the anchor bolt, place a strip of neoprene gasket between the liner and batten strip an d secure the batten strip with washers and nuts.

Liner can be attached to concrete structures. This attachment is acheived using stainless steel batten.

The stainless steel strips are attached to the concrete by inserting stainless steel wedge-type anchor bolts into the concrete.

A pipe boot is a "sleeve" that allows mechanical piping to be placed as needed without destroying the integrity of the liner.

An undersized hole is cut in the center of the sleeve, stretched over the pipe, creating a flange of material. Wrap pipe 12" and tie into flange of material. Stainless stell clamp sleeve to pipe.

Pipe boots can be pre-made to your liner type and outer-diameter pipe specifications. Shipped with the liner to your site, this step reduces field installation time.

Panels around piping penetrations are cut with rounded corners to prevent tear propagation.

90-degree and slope boots are also available.

Driving on the liner is permitted only with a 12" dirt covering. No excessive speeds, no sharp turns.

Disclaimer: These guidelines are for informational purposes only and are intended as illustration or general information only and are not intended as a guarantee or warranty. Colorado Lining International assumes no responsibilities in connection with the use of this information.