Up to now, heavy rain has been the cause of the most significant
problems for many companies. During severe downpours, the challenge
is to prevent water from penetrating buildings and to drain it off
in an efficient and controlled manner.
Heavy rainfall can impact a building from three directions: from
above, from the side and from below. It is particularly important
to remove water from large roof surfaces. If the roof is flat, and
drainpipes are blocked with leaves or other debris, the water may
not run off properly or may accumulate on the roof. In rare cases,
the roof may collapse. Water can run over the edge of a roof for
example, or through cracks in the roof's surface into skylights,
electrical installations, ventilation gratings etc. All in all, it
is important to notice where the water goes if it is not able to
run away through gutters, drainpipes and wells.
If there are large areas of concrete, asphalt or flagstones, large
volumes of water should be channelled into sewers or to areas that
allow the water to seep away. Check the ground around buildings to
see whether there are any hollows or sloping ground that may allow
water to reach and perhaps penetrate buildings. It is also
important to note that the capacity of sewerage systems is
inadequate in many areas, which can mean that water penetrates
buildings via the sewers.
In some cases, it will be a matter of insufficient capacity in the
sewers; in others a matter of regulations against the channelling
of water into the sewerage system. Where such conditions apply, it
may be a good idea to consider installing a dry well under a car
park or channelling the water into an area in which a temporary
lake would not represent an inconvenience.