House underpinning refers to the process of repairing a foundation so that existing problems (such as foundation settling) are solved. Many house-underpinning methods exist, such as mud jacking and using helical piles. This article discusses some key considerations that you should have in mind as you select a house underpinning method for your home.
Extent of Access
Some underpinning methods (such as the use of precast piers) require the use of heavy machinery. It may be difficult to move such machinery to the congested site so that the underpinning system is driven into the ground. Such congested sites may call for the use of wall anchors. This is because this underpinning method can be used in places with limited access (such as a street with houses that are very close to each other).
The Water Table
How high the water table is in your area can also play a role in determining which underpinning method is suitable. For example, it may be inappropriate to use the mass-concrete method to create a foundation underneath the existing foundation. This is because the high water table may still cause the ground underneath the added foundation to settle. It may be better to use screw piles in such a location. Screw piles are ideal because they can be driven deep into the solid rock underneath the home. This provides stability from the changes caused by seasonal fluctuations in the moisture content of the location.
Your Additional Objectives
You may wish to create a usable basement in your home. This objective can motivate you to select the use of screw piles and mass-concrete underpinning. This approach enables you to use the piles to support the foundation as you excavate a void to create a basement. The blended approach keeps water out of the basement while strengthening the existing foundation so that it does not cave in during the excavation process.
Some municipalities may have regulations restricting the options available to homeowners that wish to underpin their homes. Such restrictions may be imposed in order to reduce how much damage is done to nearby structures during the underpinning process. For example, the use of heavy machinery to drive piles into the ground can cause vibrations that can damage surrounding properties. Contact the local authorities to confirm which underpinning methods you can use.
Hire an underpinning contractor to take you through all the available options before you make such an important decision regarding the structural integrity of your home.