Laying the membrane
The application of the
membrane must be carried out only when the conditions of the substrate and of
the environment will be suitable, as described below. Provision should be made
for expansion joints, according to the nature and dimensions of the structure;
in these areas the membrane must be made independent from the I substrate, with
all arrangements suitable to the specific situation.
In all cases, it is
always necessary to unroll the membrane on the substrate surface in its final
position and then re-roll it ready for bonding. This procedure allows to detect
in time any possible defect either in the waterproofing sheet or in the
substrate. A check must be made to ensure that the correct, torchable side of
the membrane is the one in contact with the substrate.
The torch flame
must touch lightly the surface of the membrane and be in the direction of the
substrate. This brings the bituminous compound to the correct fluidity without
damaging its plastomeric components, and in the same time prepares (by heating
it) the substrate which is then in the ideal condition to "receive" the adhesion
of the waterproofing compound.
A valid indication of the time of heating
of the bituminous compound is given by the colour of the flame of the torch.
When it changes from blue-yellow to red with emission of smoke, this means that
combustion has started and deterioration of the membrane will follow. This is
when the heating of the membrane must stop.
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