Dampness is generally defined as unwanted and excessive water or moisture. The existing of dampness in building is one of the most damaging failures that really must be taken care of. It can cause damage in brickwork by saturating them, decaying and breaking up of mortar joints, rotting in the timber structures, defecting by the corrosion of iron and steel materials and also destroying the equipment in the building. Dampness in walls has been taken in consideration in recent years.
If even the level of dampness is low, the value of the building can be highly affected. Dampness can be a serious matter, particularly to the building located near water sources. Somehow, the water can enter the building bit by bit through different routes resulting in dampness. Furthermore, prevailing wet wind and rain will due to water penetrations that occur through walls.
Dampness also occur when water penetrate through capillaries or cracks between mortar joints, and bricks or blocks before building up trap moisture behind hard renders. Moreover, contribution of dampness is due to the existence of gravity. The other factor such as leaking gutters or down pipes, defective drains, burst plumbing, and condensation due to inadequate ventilation also can be the factors yielding to dampness occurrence. Dampness in building originated from a number of sources such as:
a) Rain:-
Precipitation can be wind driven that it penetrates joints that remain watertight in normal weather condition. The gutter overflow also can collect and be the aspects of dampness against walls.
b) Condensation:-
Humid air condensation on cooler surface or within, or between, building materials also can result to dampness. Air can become humid in several ways, including from the occupants’ water vapours.
c) Rising damp and flooding:-
It may be contract with groundwater or floodwater. It also the groundwater may be absorbed by the walls and transported up the wall by capillary action.
d) Services leaks:-
It may not just from pipes and tanks, but also the overflowing of condensation forming together with ventilation systems.
e) Construction process:-
The construction process too can play its role in this scenario. It is where the process of mixing water to form mixtures that dry out for the construction purpose before the building is functioned, but sometimes by retaining moisture (sealed in by impermeable finishes) that shows and causes problems in the completed building.
f) Use of the building:-
This may includes the cleaning of the building, spills, and apparatus leaking.
g) Moisture in the air:-
It is in contrast with condensation. Hygroscopic salts can extract moisture from the air in condition that would not allow that moisture to undergo the process of condensation.
