| Introduction
A number of means have been put forward to control the effect of water in buildings. Of all these means, rain screens are certainly the best at preventing water from seeping into buildings. This construction technique regulates the impact of the various forces that are on the outside of the building. The pressure differential, capillary action, gravity, and air movement constitute the main elements in these forces.
Even though it is referred to regularly to explain the cause of water seepage, capillary action is certainly the phenomenon that is the least understood. In the laboratory, capillary rise is the height attained by water in a capillary tube when its base touches the water. In practice, this makes it possible to determine the height rain water can reach when a material comes in contact with the water and is drawn up through a crack within the material or between its constituents. Capillary rise can take place in any situation in which there may be water seepage within cracks separating two materials.
This study is therefore aimed at determining for various cladding materials (brick, precast concrete panels, aluminium, wood and vinyl siding) and the exterior surfaces of doors and windows:
ˇ¤ capillary rise within a crack based on the size of the crack;
ˇ¤ the angle of contact of rain water with construction materials;
ˇ¤ the clearance between two horizontal surfaces that allows rain water to cling between them;
ˇ¤ the maximum height that rain water can reach on a horizontal surface.
Methods and Results of the Study
Samples of prepared materials and water were brought to a temperature of 200ˇăC.
The surface tension of the rain water collected was measured and compared with that of distilled water.
On average, the surface tension of the rain water measured was 71.1 dynes/cm and 72.0 for distilled water. The quality of water therefore has little impact on this property. |