Hardly anything can shake your confidence in a building more than cracks on its wall or floor .This is taken to be the smoking gun evidence of deployment of substandard building materials and poor workmanship, which can sent the value of the house into a tail spin. However these cracks can also be caused directly by a building’s relative movement either partially or as a whole. Which in turn has nothing to do with quality of building materials deployed but everything to do with lack of great workmanship. Parts of building or the whole building structure will experience unwanted movements because of either one of the following phenomena: settlement, changes in temperature, variation in moisture levels, wear and tear or building loading.Embed from Getty Images
The settlement and uplift all buildings experience is the result of building’s load on the foundation. Settlement is slow and act in one direction causing a shearing effect on sealants like mortar and mastic used in joints. If this shearing is great, it may lead to structural cracks which obviously is not sweet music to ears of those who have invested in it for the long haul and are not ready to deal with recommendations of the county and national building authorities.
Also settlement can be caused by dynamic forces like earthquakes and explosions.
Temperature variation within a day and between seasons can cause a building’s various parts to expand and contract. The amount of these contraction depend on the materials used. Timber has the least movements with any drop or increase in temperature. Glass, steel, bricks, stones and concrete have moderate reaction to changes in heat in the atmosphere. Last but not least, plastics and Aluminium exhibits astonishing expansion or contraction when it becomes hot or cold.
Again consider before-hand using dark colours , good insulation and thick construction materials on your building ;they respond better when the weather changes from cold to hot or the reverse. Which of course means, minor movements in the building parts.
Regardless of the weather conditions, concrete and mortar will show initial contraction when it cures, timber will show little shrinkage if properly seasoned and bricks will expand if used immediately after firing. Depending upon the atmospheric fundamentals, moisture and heat related movements may resist or complement each other.
Moisture exposure in building is mainly due to wall penetrating rain water, damp soil, high water table, pipe leaks inside the wall, and open water in the event of high flooding.
This moisture is likely to cause deterioration on the building interior finish and pre-mature aging of wooden parts because of the attack of mould and fungi. Also moisture is likely to cause corrosion and rust on metal parts like windows and the roofs.
By the same breath, deterioration of materials such as corrosion of steel or sulphate attack on concrete is often associated with irreversible expansion causing movement of adjacent components. Again concrete structures may exhibit creep which is a gradual permanent deformation under load over many years.
Dead weight is responsible for initial building settlement. However movement associated with live loads like Cars, human traffic and wind can cause perpetual cyclical movements within a building components.
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Sources: 1.Materials for Architects and Builders by Arthur Lyons