Container leaks must always be expected. The roof, floor and container door areas are particularly likely to leak.
If the spreaders are not positioned accurately, they may be set down on the container roof next to the corner castings. Setting down of a spreader on the container roof may be done very roughly, resulting always in the risk of direct damage and subsequent rusting through. If this happens repeatedly, the container roof may suffer serious damage, resulting in leaks, especially at the points which have by then rusted through.
Forklift trucks may cause the container to bulge upwards and these points then corrode, leading to leaks in the floor area.
Leaks frequently occur in the container door area. By way of example, the doors of a refrigerated container warped as a result of damage to the container roof, so that rainwater could get in, forming a layer of ice in the area of the doors.
However, leaky rubber door gaskets on refrigerated containers may also allow rainwater to enter in the door area, forming a layer of ice.
Leaky doors on standard containers have also resulted in mold damage to malt which was being transported from Europe to Japan as a deck cargo. This was dealt with by fitting a plastic curtain to protect the container doors from moisture penetration.