One sign that your house's foundation is unstable is that there are creeping cracks along the walls. Or else, doors might jam and not fit squarely within their frame. However, problems like these can be caused by other issues as well. Only an underpinning expert can judge. In fact, this process uses different experts, as explained below. Additionally, various methods can be used to fix the problem.
Expert Structural Engineer
Structural engineers are trained to analyse the integrity of buildings and structures to ensure they're sound. These experts are an excellent first step in investigating your home's problems. Because they don't carry out the corrective construction work, they don't have a vested interest in the results of their investigation. So their analysis will be independent. They'll give you a report of the problem and suggest solutions.
They may also involve a geotechnical engineer or a soil expert. Doing so will help them work out the cause of the problem and the role the soil type plays. Some soils are sandy, for example, and this impacts buildings. Once you have this independent assessment of the cause and possible corrective procedures, you can approach an underpinning construction company to carry out the work.
Underpinning Construction Experts
An alternate approach is to first approach a company that specialises in underpinning construction. They'll then hire their own structural engineer. However, they may add a surcharge for organising this. Plus, you might not be as confident in the independence of the advice.
If it's determined that underpinning services are required, the contractors may insert steel or concrete pilings that reach deeper into the earth than the current foundations. That way, they'll get past the unstable soil nearer the surface.
Another solution is to excavate and pour concrete around the existing foundation to increase its mass. Depending on the engineer's report, they may instead inject resin into the earth to make it clump and harden. This will produce a more solid cradle for the foundation and house to rest in.
Inserting new pilings and concrete will require a lot of excavation and can be quite disruptive. Your property will be an eyesore while the work is in progress. The resin injection method is less intrusive as holes are bored into the earth. However, the best strategy is the one that works and follows the advice in the structural engineer's report, as this will take care of the problem in the long term.
If you need residential underpinning, reach out to a contractor in your area.