Underpinning

Underpinning is a method used to increase foundation depth or repairing faulty foundations. This might be the case if you plan to add stories to an existing structure or when the foundation has been damaged. One visible sign that your building needs underpinning are cracks appearance. When a building needs a foundation repair some cracks, especially wider than ¼ inch appear visible, meaning than an underpinning needs to be done. Foundation failures could also be considered as heaved foundations, cracked or buckled walls and cracked concrete floors.
Underpinning: Mass Pour
The most used method of underpinning is mass pour method. Excavate sections in sequence to a pre-established depth below the footing and place concrete on each pit. Repeat the method until the entire affected area has been underpinned.
Underpinning: Screw Piles and Brackets
Underpinning with screw piles and brackets is normally used in certain instances where traditional underpinning process is not possible.Some buildings might require excavating to great depths or maybe is unfeasible to use a piling rig and the screw piles and brackets method is then selected. The screw piles and brackets can be installed by only a two man crew by hand or using small equipment such as a mini excavator. Screw piles can be installed in foundations having the capacity to work in tension and compression, withstand vertical and lateral wind forces, and vibration and shear forces. They are ideal when used with underpinning support brackets. The structure can then be lifted back to a level position and the weight of the foundation transferred to the pier and bracket system.
Screw piles have many advantages over traditional pilings, such as the speed of installation, little noise and minimal vibration that may cause damage to the surrounding area.
Underpinning: Pile and Beam
Underpinning with pile and beams is another great and preferred method to alleviate footing. Using this system requires that a min-pile must be