House Underpinning: The Process and Necessary Steps

House Underpinning is construction of additional and stronger footings to strengthen or stabilise an existing residential property. There are many reasons due to which underpinning may be required. If the original foundations is not strong or stable enough then underpinning is required. When the properties of the soil supporting the foundation or the structure has changed at that time also underpinning is required. Sometimes nearby structure construction makes it necessary to excavate the soil supporting existing foundations. Sometimes it is necessary to increase the depth or load capacity of a building to support an additional storey. Many a times it is economical to work on an existing building than to build a new one. Natural calamities like floods, earthquakes or drought can lead to requirement of underpinning activity.

Underpinning normally involves digging the new bored pier footings besides a house at about two metres to three metres centres. Footings need to go deep enough into the soil which is strong enough to support the weight of the building. The deeper footings need to be joined to the existing building. Often this is achieved by digging under the existing footing to make a strong prop for existing footing. The arrangement of prop and pier is reinforced with bars of steel and filled with concrete.

Most underpinning contractors first recommend an inspection by a structural engineer. This is required to identify and diagnose footing movement which could reverse with change in soil moisture conditions. It is recommended that independent soil tests be performed before investigation. The structural engineer can specify the diameter, depth and spacing of the underpins based on the type of construction of the building, strength of the soil, type of soil and amount of footing movement. A contractor is required for arranging building approval and installing underpins. For more information on house underpinning visit company CornerStone Foundations.