The answer to this question is multi-faceted and broad in scope, ranging from complex structural issues which threaten the integrity of buildings, to aesthetic issues such as improperly painted and deteriorating wood trim around windows. However, typically, courts have recognized the following general defect categories:

1. Landslide/geotechnical problems - There exists a great deal of expansive soil in Southern California and Arizona. If these lots are not properly compacted and prepared for drainage, problems inevitably result including vertical and horizontal settlement or movement, slope failures, flooding, landslides and the like. These conditions lead to cracked foundation slabs and damage to the building, in the worst instances render a structure uninhabitable.

1. Design deficiencies of buildings and/or common areas - Often design professionals such as architects and civil engineers design buildings and systems, which, as a practical matter, simply do not work. The focus may be on aesthetics or cost, and the result, not infrequently, manifests as a defect. Problems involve: roof systems, which, due to their complexity are prone to leak; improper choice of building materials resulting in water intrusion or other problems; poor drainage design and inadequate structural sections which result in cracks and deterioration of pavement, etc.
2. Substandard/poor workmanship - Poor workmanship often manifests as water infiltration through some portion of the building envelope; electrical problems; dry rotting of wood or other building materials; termite or other pest infestations; plumbing back-ups and leaks; lack of sound insulation or fire-resistive construction between units, etc.
3. Deficiencies with respect to building materials - It is not uncommon to find windows which leak or otherwise fail to perform adequately, even when properly installed. Other common manufacturing problems with building materials include deteriorating pipes, waterproofing membranes, and asphalt roofing shingles.