Once you have determined that the building is not in imminent danger of falling down, the next task is to determine what is causing the cracking to occur. This can be down to many factors. Typical examples include poor drainage running under the foundations, causing erosion of the sub soil. The sub soil might be drying out, resulting in shrinkage of the soil under the foundations. This can be caused by a dry summer; lack of rainfall leads trees and vegetation to reduce soil moisture levels. As the soil
shrinks, the building settles on the foundations, leading to the generation of cracks.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /?>
Cracking may be caused by a defect in the original design of the building, or by structural changes that have been made to the house after it has been constructed. A classical example of this might be the removal of a chimney and fireplaces. When the architect originally designed the house, he relied upon the chimneybreast for structural support. If this is removed, is the property still structurally sound? Another classical problem which causes cracking is changing the slate roof for a clay tiled roof,
the clay tiles are about five times heavier than slate, are the walls and roof structure man enough to take the extra weight?
To complicate matters, the cracking may be caused by a number of factors, which come together, interact, and cause the failure to occur. One has to read the building, and diagnose the problem. In many ways the building surveyor is more of a pathologist, than a surveyor.
The next stage of the process is to determine whether the crack is getting bigger, or whether it is stable. Building surveyors tend to use glass tell tails screwed across the crack. They in effect are two rulers which sit side by side. If the crack widens, the surveyor will be able to measure the difference in the gap. And determine what is going on.
If the crack is moving, we will know that remedial work will be required to stabilise the wall, and that point, one tends to pass the problem back to the building's insurer, and make a claim.
In this case, we are at the very early stages of the process; it will be interesting to see how it develops over the coming months, but no doubt it will be a source for a few articles to come.