One of the most pervasive issues we come across in our construction business in Charleston SC is foundation failure. It's not a great outcome, but with a little thought and the right help all things are fixable. This is specialist work and we use trusted sub-contractors to remedy, rectify, lift and replace. Here are a few thoughts from one local team that are experts in their field:In downtown Charleston the two most common causes of foundation failure are chimneys and earthquakes. Chimneys are the heaviest part of the building and when sat on the muddy soil of the lowcountry for a 100 years or more they will shift, moving the building in the process. For a major renovation, if the chimney plays no role and does not add aesthetically to the building, then consider removing it. Sometimes all that is needed is a faux chimney above the roofline to restore the visual effect. If the building is being lifted more than 12 inches, then again consider removal as the hearth will disappear into the floor. Earthquake is responsible for many leaning buildings in Charleston. In most cases the owners live with the long-term effects and quite like the quaint leaning it produces. For a major renovation we would recommend rectifying the structural lean before replacing anything internally since everything rests on a foundation.
On newer properties, especially those built as tract homes, then improper framing can have the same effect as foundation settlement - drywall cracks, doors swinging open or not closing, or windows jamming. It's a structural issue, but once identified it's usually easy enough to solve with additional bracing.
Soil movement can be caused by improper compaction during construction. Have you ever seen a ranch style house where the slab has failed and zig zag cracks formed in walls typically following the mortar lines in brickwork? This is the result of "ground heave" (heave from dry soil absorbing moisture or moist soil drying out - especially clay based soils). Drying can be seasonal or caused by other nearby construction and drainage. Even simple things like a long term plumbing leak or blocked drain can cause localized heave. Again, once understood then remedy is easy enough but may involve extra underpinning down to a more stable soil layer.
Trees. We all like trees near our homes though preferably not touching them. That shade from the summer sun is a welcome addition to any property. Trees take up a huge amount of moisture and can cause large changes in soil conditions. Some trees are particularly invasive and can also cause physical cracking of concrete foundations and blockage of drains. Willow and Eucalyptus are two good examples of this behavior. Large old oak trees have been on your lot for a very long time so conditions should be stabilized. Young, fast growing trees are the ones to watch out for.
Note: So if it's earthquake damage, leaning chimneys, cracks, settlement, broken slabs, soil heave, or whatever foundation issue you experience, the one certain thing to remember is that with expert advice and support, even the most severe issue is usually not as problematic as it may first appear. The one thing we can't fix is landslides, but that's not really an issue here in the very flat lowcountry.
With thanks to Travis Bedson of CNT Foundations