The foundation is the most important part of your structure. Foundations are typically made up of concrete footings laid underground as the structural base for a poured concrete or CMU block wall. Foundation problems should be addressed as soon as they are discovered and before the damage is irreversible. The two most common types of foundation failures are foundation settlement (vertical movement of the footers) and foundation wall bowing (lateral movement of below-grade walls).
Foundation Settlement
Typical signs of foundation settlement are stair-step cracks and vertically sheared bricks or blocks. The most common and typically most economical method for repairing failed, settled foundations is to install a series of steel underpinning piers below the affected area. The concept is based on the principle of turning or pushing an anchor into stable subsoil strata until the applied torque or pressure indicates that the required load capacity has been achieved. The load-bearing steel shafts are installed independently of the structure, and their bearing or holding capacity is verified for each pier as it is installed.
Adjustable brackets are then attached to the base of foundation walls, connecting the anchors to the foundation. The home’s weight is then shifted to the anchors. In the process, foundations, walls, and floors are repositioned and held to prevent further movement.
Bowing or Leaning Foundations
Bowing walls often have a long horizontal crack running from a corner foundation to the opposite corner of the same wall. This crack is typically within the middle third of the wall, but can be in the upper third as well. Horizontal cracks in the lower third of the wall are often associated with a shift or offset of blocks rather than a bow of the wall.
These here are the most common remedial methods of stabilizing bowing walls are installing a series of (A) vertical struts or I-beams, (B) wall anchors or dead-man anchors, and (C) carbon strips. Each method has its own advantages and disadvantages and not all methods can be used in every situation.
Damaged Framing
Framing is the backbone of any construction project. The most common types of damaged framing are: cracked or cut roof trusses, bowing or twisting of joists and beams, column bowing, and inadequate connections between framing members. For example, one of the most common in a home improvement situation is a handyman cut where they probably shouldn’t have to accommodate pull-down attic stairs. An inexperienced handyman or homeowner can unintentionally weaken the roof truss and framing system, which ultimately can lead to roof failure.
Retaining Wall Damage
Most retaining wall failures are due to inadequate drainage behind the wall to reduce hydrostatic (water) pressure. Active failures include bulging, leaning, bowing, and material deterioration due to high moisture content of the retained soils.
A proper drainage system will capture and redirect surface water infiltration behind the wall, thereby dramatically reducing hydrostatic pressure.
Most situations can often be rectified and stabilized, and save existing retaining walls by excavating behind them and installing drainage systems rather than demolishing and rebuilding. Stabilizing a retaining wall rather than rebuilding can yield significant cost savings.
Wet and Damp Basements
Wet basements or crawl spaces are often sources of immediate and long-term problems. Standing water inside and/or seepage into residential crawl spaces and basements can cause many problems for the homeowner. Wet basements and crawl spaces are sources of high humidity, which can produce surface condensation, mildew and fungi, musty odors, and an unhealthy environment. Such moisture can also cause deterioration of floor joists, beams, sub-flooring, insulation, and electrical and mechanical systems. Prolonged water around the footer and foundation wall can soften the soil and weaken its bearing capacity, increasing the possibility of foundation wall movement. Serious seepage beneath the foundation footer may erode the soil and cause the wall to settle and crack.