What Is Involved in Underpinning a Home?

Underpinning is a good solution for a home with a severely damaged foundation, which has caused it to settle in any one direction. This process can make your home level and even once again, and protect it from future damage. If you've been told that your house may need underpinning, note what's involved in this process so you know if it's the right decision for your property.

Reason for damage is first addressed

Underpinning a home starts with the digging of trenches around the foundation, so that the area can be thoroughly inspected and the reason for damage to the home identified and fixed. Without doing this first, the foundation may easily get damaged again, even after underpinning.

As an example, it may be discovered that water is collecting around one area of the foundation, and your property needs to be better graded or a retaining wall needs to be built. A contractor may see that the soil around your home is very sandy and soft; you may need to add lime or clay to the soil to make it firmer. These things may need to be done before the underpinning can be completed.


Your home will usually need to be levelled before the pinning of the foundation is done; it may literally be jacked up at one end, or mechanical piers or blocks are pushed underneath the foundation. This will  prevent your home from continuing to sink in that area after the underpinning is completed.


Pinning the foundation is then done; this might include actual pins that are installed around the foundation, or it may mean an added layer of concrete that will make the foundation stronger. The type of actual pinning needed for your home will depend on the amount of damage to the foundation, and if it's strong enough to support your home after the levelling process. Trenches are then filled in to cover over the work and restore your property.

Exterior and interior repair

Once the home is levelled and the foundation pinned, exterior repair is performed; this would include patching up crumbling brick and mortar around a chimney and repairing existing cracks in the foundation. Waterproofing may also need to be replaced.

Inside the home, the beams of load-bearing walls as well as joists in the sub-floor may need to be checked for damage and replaced as needed. You can then also repair any cracks in the walls and ceilings or along timber floors. For more information, talk to a professional like Jeffrey Hills and Associates.