If the foundation walls don’t appear to have any bowing, bulging, or movement, then the solution may be simple. First, look at how close trees are to the home. Tree roots can extend outwards for a distance equivalent to at least the trees height, and in some cases a lot longer, depending on the soil conditions and/or tree type. Do some research if you’re unsure about the species of the trees. Next, inspect the gutters, downspouts, and downspout extensions to be sure they are clean, undamaged, and that the downspout extensions extend at least 6 feet from the homes foundation. In addition to the gutters, proper grading plays an important role in keeping water away from the homes foundation. The ground around the foundation should be sloped to direct rain water away, keeping the soil from becoming too saturated, allowing it to cause pressure against it.
If everything on the exterior looks good, let’s look at the interior. Does the basement have a sump and pump? If not, your trouble may be a result of hydrostatic pressure. If a sump and pump is present and working properly, you may be looking at backfill related foundation cracks. These are usually the result of poor backfilling, large rocks, frozen chunks of soil, and/or backfilling before the concrete has cured enough.
If unsure of the possible cause, a foundation inspection can be done to determine if there are any noticeable defects that could cause the foundation issues. Horizontal cracks with signs of bulging, bowing, or leaning should be examined by a foundation specialist, who can assess and recommend possible repair solutions. For example, adding buttresses, pilasters, wood, steel beams, or channels to the inside of the foundation walls. An interior wall built against the foundation wall, or an exterior wall (sister wall) built against the foundation can also be used. Helical anchor screws can also be screwed into the outside ground, with plates on the interior, preventing the foundation wall from moving any further inward. A foundation specialist can advise you of which solution is best to provide the required support for your foundation.
Horizontal cracks with no signs of movement can most times just be properly sealed, and monitored for movement. Don’t be scared by the often used term “foundation failure”, because in some cases it may not be as bad as you think.