Chapter 19, Problem 1RQ

To determine

Write the reasons for the difficulties faced to make cladding watertight.

Explanation of Solution

The forces due to gravity, momentum, surface tension, capillary action, and wind pressure that cause water leakage make it difficult to handle. Gravity is a factor in which water is pulled through the wall only if the wall contains an inclined plane that slopes into the building.

The falling raindrops’ momentum drives water through a wall only when the wall has a suitable oriented hole that goes fully through the wall.

The water to be drawn into the building due to the surface tension of water causes it to adhere below the cladding component.

Capillary action is the effect of surface tension that pulls water through any opening that can be bridged by a water drop.

The water tightness of cladding is difficult because wind can drive water in any direction on the building’s face as well as through any openings. Any crack or crevice will cause the water to enter. This problem takes place in very tall buildings, where high wind velocities at upper levels produce abnormally high velocities and pressures.