|  Upcoming articles will include case studies of disputes and lawsuits involving other masonry issues. | |
Upcoming articles will include case studies of disputes and lawsuits involving other masonry issues. |
Previous articles in this series covered general principles and drainage. The first article states that lawsuits can be minimized by good ethics, well-written contracts, clear communication, and by following directions (e.g., building codes). The second article illustrates how to avoid inadequate drainage, which moves the foundation and is the most common cause of masonry distress and lawsuits. This article addresses the foundation itself, which is the second most common cause of masonry distress and lawsuits.
Code Principles
To minimize movement, the foundation is required (IBC* 1604, IRC*R401.2) to be designed and constructed (of masonry or other materials) to carry the loads from the building (or other structure) to the supporting earth. Loads from the structure include (IBC*1603, IRC*R301.1) dead loads from the structure itself, live loads from use and occupancy of the structure, and environmental loads such as wind, rain, snow, water action, flood and earthquake. The loads carried through said foundation to the earth are required (IBC*1804, IRC*R401.4.1) not to exceed the capability of the earth to support said loads. Failure to comply with these code principles is a major cause of foundation movement and resulting masonry distress.
Case Studies
The following examples (from the author’s expert witness cases) illustrate inadequate masonry foundation design/construction, and illustrate inadequate non-masonry foundations causing masonry distress.
Case #1: Masonry Pier/Beam Foundation. A large percentage of small buildings nationwide (existing and proposed) have a concrete masonry unit (CMU) pier and beam foundation, which can be a practical and economical choice. Unfortunately, many of these foundations do not comply with building codes (and do not comply with loan requirements of the Federal Housing Administration and Veteran’s Administration). These code violations cause economic loss, injury and death (particularly with wind or flood loads), and subsequent lawsuits. One such case, a manufactured home (Photo 1), did not comply with:
a. Required foundation depth below ground (IRC*R403.1.4),
b. Securing of piers from footing up through CMU to house framing (IRC*R401.2),
c. Drainage slopes away from building (IRC*R401.3, R403.1.7.3).
These masonry foundation problems caused moving and cracking of the walls and roof, water entry into home, organisms (mold), and risked injury and/or death. The solution was vertical steel into new concrete footings and up through the hollow CMU, secured to the beams, and then the hollows filled with concrete grout. These costly problems and this costly litigation could have been avoided by complying with the building code.
Case #2: Post Tensioned Foundation. Cracks continued to worsen in masonry siding, in slab, and in drywall in a building on a post tensioned foundation on expansive clay (Photo 2). These cracks were caused by violations of foundation construction plan requirements (“a” through “f” below) and by violations of foundation building code requirements (“g” through “I” below):
a. No removal of bad soil.
b. No proof rolling sub-grade.
c. No select fill.
d. No compaction or compaction testing.
e. No thickened slab in high-stress areas.
f. Missing steel reinforcement.
g. Inadequate concrete consolidation (IBC*1905.10).
h. Inadequate slab elevation above public drainage (IBC*1805.3.4).
i. Inadequate drainage around building (IBC*1803.3).
The estimated cost to repair exceeded the estimated cost to remove and replace the building. These costly foundation problems (that showed up first as masonry cracks) and this costly litigation would have been avoided if the building contractor had followed the requirements and/or if inspections were performed by competent personnel (e.g., a licensed professional engineer).
Case #3: Slab/Gradebeam Foundation. Extensive cracks in masonry siding (Photo 3) and interior drywall cracks, stuck doors, and excessive slab elevation changes were caused by violation of foundation code requirements in a reinforced concrete slab/gradebeam foundation. These code violations included:
a. Load exceeding soil bearing capacity (IRC*R401.4.1),
b. Shallow gradebeams (IRC*R403.1.1),
c. Slab out of level (ACI*4.4.1) and excessive slab slopes (ACI*4.8.2),
d. Inadequate drainage (IRC*R401.3, R401.7.3).
The solution included engineered exterior and interior piling. These costly foundation problems and this costly litigation could have been avoided by complying with said requirements.
