Figure 26. Placing top
membrane during light
winds.
Cutting the final grade or removing any excess
after it is placed on the membrane. The Poly Seal
soil from the edge near the membrane requires
tape is permanently adhered to the plastic as soon
great care. It may be necessary to use brooms or
as it touches it.
shovels to remove excess soil.
It is recommended that both tapes be kept
above 10C (50F) before use, e.g., by keeping the
It is critical that the top surface be smooth with
no loose material. Because the upper membrane
tape in a heated vehicle. It is also possible to heat
is not protected from the fill material and small
the tape and the membrane with a heat gun as the
stones, hard soil particles, etc., can easily punc-
tape is being applied. (As mentioned in the
ture the membrane. Small stones may be tracked
"Membrane sealing" section, using a heat gun
on the surface by vehicle tires, shoes, etc.
would require a generator.)
Sealing membranes. The membranes must be
Placing, compacting, and grading the encap-
clean for the tape to bond properly. Dust quickly
sulated soil. This is one of the most difficult steps.
accumulates on the membranes. If the soil becomes
The initial lift must be placed carefully to avoid
wet at any time the membranes may become
damaging the lower membrane. Care must also
muddied and then must be cleaned. The mem-
be taken when spreading and compacting near
branes can be cleaned with water and, if required,
the sides of the membranes. The membrane can
rubbing alcohol.
be torn easily by the heavy equipment (Fig. 27).
Figure 27. Membrane tear.
17
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