Foundation & Basement Wall Cracks
As with all of my engineering consultation/designs, you will be presented with a detailed written proposal of the Scope of Work for your review, including fee, prior to commencing.
Foundation cracks are a VERY common item cited by the Home Inspection Report, and unfortunately create a lot of anxiety for both sides. Again, keep it in perspective; houses rarely fall down or cave in. You likely are aware of three types of cracks – vertical, horizontal, and stepped. Briefly summarizing, the vertical crack is usually the least worrisome and can be attributed to the development of tensile stresses which exceed the tensile strength of the masonry materials. These tensile stresses may be caused by wall movements due to a temperature differential, change in moisture content, live loading adjacent to the foundation, or actual masonry movement due to settlement or other forces. Typically in and around the garage, soil is not properly compacted, while the footings tend to be shallower, thereby being more susceptible to freeze/thaw cycles. Another possible explanation could be attributed to footing settlement in which the footings have "bent" and settled unevenly, such as when a footing has been placed over unevenly compacted fill or where there was a large boulder under a portion of the footing permitting settlement such that the footing has settled down on one or both sides of this "high point". This isolated fulcrum may be the reason for the crack as the stress could radiate upward as is seen.
Horizontal cracks on the other hand, can run the gamut of minor shrinkage cracks in the mortar, to significant bulges caused by excessive pressure behind the wall. Many times the latter is due to poor drainage, which is also related to the soil, but can be for other reasons like inappropriate use of construction equipment, poor methods of construction, hillside loading, aforementioned freeze/thaw cycles, and lack of necessary wall reinforcement such as pilasters. Stepped cracks are a wild card as they can be due to the same reasons as mentioned above. Suffice it to say that the mortar is the weakest component of the wall, so the crack develops along this plane.
Blue Line Stone Home & Engineering will assist in the following manner. First, I will review any prior inspection reports and/or building plans, then:
• Visit the site to observe the phenomenon, take measurements and pictures, determine the structural members and ensure it is adequate for loading and able to perform as designed.
• Identify the problem and potential causes.
• Prepare a Findings Report which documents the above, and provides a conclusion and recommendation(s). There are generally three scenarios:
Do nothing or “it can wait” (or some very minor repairs)
Identify if it may get worse and take corrective action
Immediate repairs necessary
• The three scenarios may warrant a range of action from merely sealing the crack, to reinforcing it, to demolition and reconstruction. If either of the last two are desired, signed and sealed drawings will be prepared for submission to the building department for the necessary permit.
• BLSH&E will present a cost estimate for repair, and assist with obtaining a qualified contractor for the construction.
And by the way, in the picture above, those cracks are likely due to the water that collects in the window well and has nowhere to go except saturate the soil and push on the wall.