There are several reasons that render can deteriorate, both naturally and by human activity.
As a force of nature, weather is out of the control of all humans and this could be the first problem. The role of render is to protect the main walls of a property from the most extremes of weather; extreme heat, heavy rain and wintry conditions are just a few types of weather that can affect the condition of render. Over time the render begins to give way and shows signs of wear and tear. The harsh weather can start to rip chunks of render off the wall and this begins the process of deterioration. However, weather is not the only reason for render deterioration but also, the lack of human activity.
When render begins to deteriorate, it needs to be repaired as soon as, to prevent the problem getting worse. Neglect, is another way that render can deteriorate. Many people assume that once the rendering is done, that is the end of it. But that simply is not the case. Once signs that the render may deteriorate occur, the render either needs to be repaired or replaces. Simply neglecting or dismissing the signs will cause the render to continue to deteriorate until all the render has broken away from the wall. An example of neglect can include leaving a leaking downpipes. At first it may not appear to be damaging any of the render and so people tend to leave it, however, by leaving a leaking downpipes the render is actually deteriorating and people do not realise until they have fitted a new downpipe.
Another form of render deterioration is through structural movement. Structural movement can include a number of things such as sway, bouncy floors and expansion. When a wall expands, for example, cracks begin to appear which can get bigger if not treated. When these walls have render on them, the render can begin to crack and therefore deteriorate. One way that an expanding wall can be treated is by attaching an expansion or movement joint. This absorbs the pressure, taking some of it away from the wall, which can stop the expansion of the wall. This can also stop the deterioration of the render as the wall stops expanding.