There are many reasons for structural foundation movement. Most of the time it is a combination of issues that attribute to foundation movement.
Signs of Foundation Problems
- Cracks in the foundation
- Cracks in brickwork
- Cracks in the drywall
- Uneven or sinking floors
- Doors and windows stick or don’t open
What Causes These Problems?
Bad Building Practices
Many structural foundation problems are caused by some form of builder error. Many times developers do not put in the time or money needed for soil testing, backfilling, or proper compaction in a subdivision before development takes place. Therefore the foundations are under engineered and foundation movement takes place.
All soils are composed of different materials and have different strengths. The strength of the soil determines how much weight it can support. Heavy buildings are commonly built on weak soils and it creates foundation movement.
Changes in Soil Moisture
The constant change in soil moisture is the number one reason for structural foundation movement. Clay soils and some others expand and contract greatly with changes in moisture content. Clay soils soak up moisture and expand when it rains. This exerts tremendous amounts of lateral pressure on the foundation walls. This can cause the foundation walls to bow or lean inwards.
Foundations can also settle over time with extremely wet soil. Some soils soften and weaken with extreme saturation. The weakened soil cannot support the weight of the structure above it and the foundation settles. In times of drought, the clay soil releases all of its moisture and the clay shrinks and loses some of its strength. The soil pulls away from the foundation and downward settlement can occur.
Trees and Vegetation
Trees and other deep rooted vegetation cause a significant amount of structural foundation issues. Trees and other plants soak up water with their roots. This adds to the drying of the soil in drought conditions. It is common to see foundation settlement in areas where large trees are growing near a foundation. Trees can also be the cause of lateral foundation movement. Tree roots grow outwards from the tree in search of water in the soil. If a tree is planted too close to a house, then the roots will grow against the foundation and in many cases can exert enough pressure on the wall to push the wall inwards.
Underground plumbing and sewer leaks can cause foundation settlement. The soil under the footing of the house can be washed away over time. This leaves a void under the foundation and it can sink. This excess water will also saturate the soil. This can cause a weakening of the soil, which will result in the settlement of the foundation.
How is My Foundation Moving?
Foundation movement can usually be classified in two different ways; inward movement (bowing or tipping) or downward movement (settlement). Foundations can also move upwards, but this is rare and extremely hard to solve.
Foundations will move inwards when there is a tremendous lateral pressure exerted on the wall from the outside. This pressure is usually caused by tree roots and soil expansion. Tree roots extend past the canopy of the tree in search of food and water. Tree roots that are growing up next to a foundation can exert a sizable force against the wall. This pressure on the outside of the wall can cause a foundation wall to be pushed inwards. Foundations will begin to crack and break apart. Diagonal cracks will form at the corners of the walls, and long horizontal cracks can appear in many types of foundations. Sometimes the walls will tip in at the top and sometimes they will bow inwards in the middle. Tree roots can crack the foundation so badly that the only option for repair is foundation replacement.
Soil expansion can also cause inward movement. Clay soils expand when they get wet and shrink when they dry out. During the rainy season, the clay outside a foundation wall expands. This expansion puts pressure on the foundation wall. It can increase to tons of force per square foot. If the pressure increases high enough, then the wall will fail and push inwards. This pressure will continue to increase over time with the seasons and cause the foundation to worsen. This happens because when the soil dries out again in the dry season it will shrink away from the foundation. It is common for a gap to form between the soil and the foundation well in the heat of summer. This gap is part of the problem. Soil, mulch, twigs, and other debris fall into this gap during the dry season. Then the wet season returns and the soil expands again. The new debris increases the pressure on the wall and it moves in a little more. This cycle continues to get worse through the seasons until the wall is properly supported.
has the widest range of products to solve almost any inward wall movement. There is no one solution that will solve every unique situation. Each unique problem requires a properly engineered solution. Basement Authorities offers Hold Right Wall Anchors, Gorilla Wall Braces, carbon fiber technology, and helical wall anchors. Your local certified Basement Authorities' expert will go through an extensive inspection to determine what the absolute best solution is to accomplish your goals and solve your problems.
Vertical Movement (Settlement)
Vertical movement occurs when the soil under the foundation can no longer support the weight of the structure above. The foundation will begin to sink, and the rest of the house will follow. Cracks will develop in the brickwork and drywall around the house. Large vertical cracks that are wider at the top than at the bottom will form in the foundation. Floors will become uneven. Doors and windows will begin to stick or not work at all. The home is no longer stable and is susceptible to further movement. This movement can cause a tremendous amount of damage, and should be dealt with before the situation becomes extremely costly. There are many reasons for foundation settlement. Poor building practices, weak soils, trees and vegetation, changes in soil moisture, and plumbing leaks are some of the main causes of foundation settlement. The end result of these issues is that the soil underneath the footing of the foundation weakens or shrinks away from the bottom of the footing. The footing sinks with the unstable soil and the rest of the house follows downward.
The best permanent solution for foundation settlement is piers. There are helical piers and push piers. Helical piers are a series of steel pipes that are screwed into the ground. The pipes screw into the ground until they reach stable soil. Push piers are a series of pipes hydraulically driven to stable soil or bedrock. Both piering systems are installed in specific locations around the house, and are attached to the footing of the house with a metal bracket. The pier acts as a steel column. It transfers the weight of the house off of the weak soil below the footing. The weight is transferred to more competent soil deep below the surface. This soil is not subject to the changes that affect soils closer to the surface. In many cases, the foundation can be raised back to its original position. Repairing a settling foundation is extremely complicated. It takes a properly trained and experienced expert to diagnose and engineer a proper solution. It is not worth the risk to have it repaired by an inexperienced contractor. Your local certified Basement Authorities' expert has the knowledge and skill to permanently repair your settling foundation.