Underpinning is a method to support your home's foundations. Sometimes the concrete slab the supports a house can sink on one side and cause walls to crack and doors and windows to stick within their frame. When this happens, underpinning can help to restore the integrity of your home. Two basic options are available, as explained below.
If you build a second story on your home, the existing foundation may not be strong enough to carry the building weight, and it may sink without additional support. In such a case, concrete underpinning can reinforce the concrete slab in the ground underneath. Contractors will excavate the earth and pour new concrete underneath and around the slab. Alternatively, they may construct concrete pilings and submerge them into the ground. Another situation where concrete underpinning might provide a suitable solution is if the foundation was faulty in the first place.
Other foundation issues are caused by the soil around the building settling and sinking downwards. Of course, this causes the concrete slab your house sits on to shift accordingly, which can destabilise the structure, especially when it drops more on one side. Because the problem lies with the soil, your contractors may suggest another solution besides concrete underpinning. This alternative option involves injecting resin into the ground to clump and solidify the earth, making it more secure. Resin injection involves less excavation than concrete underpinning, as the filler is pumped into the ground. If you live in a coastal area with sandy soil, contractors may inject other materials to help bind the earth. This approach focuses on stabilising the soil around the foundation rather than reinforcing the foundation itself.
Thus, two common approaches are available to deal with home structural issues. Concrete underpinning helps to bolster the supporting concrete, and it may be the best option if the current slab is not bulky enough to support the building. On the other hand, resin injection may be a better approach if the problem lies with the earth surrounding your home.
You could contact a structural engineer, a specialist who assesses a building's structural integrity. They may enlist the help of a geotechnical engineer to investigate the soil. The structural engineer can then advise you of the cause and recommend possible solutions. These experts offer an ideal first step, as though you'll pay for their report, they don't have a vested interest in the process you undertake to correct the problem. Then, you can take their report to residential underpinning experts to get quotes.
To get started, contact a local underpinning service.