1. Improper surface grading/drainage: Results in water penetration in the basement or crawl space.
2. Improper electrical wiring: Includes insufficient electrical service to the house, inadequate overload protection, and amateur, often dangerous, wiring connections.
3. Roof damage: Includes old or damaged shingles or improper flashing which cause water leakage.
4. Heating systems: Includes broken or malfunctioning operation controls, blocked chimneys and unsafe exhaust disposal.
5. Poor overall maintenance: Includes cracked, peeling, or dirty painted surfaces, crumbling masonry, makeshift wiring or plumbing, and broken fixtures or appliances.
6. Structure-related problems: Includes damage to foundation walls, floor joists, rafters, and window and door headers.
7. Plumbing: Includes old or incompatible piping materials, faulty fixtures and waste lines.
8. Exterior flaws: Includes inadequate caulking and/or weather stripping on windows, doors, and wall surfaces which leads to water and air penetration.
9. Poor ventilation: includes over-sealed homes which result in excessive interior moisture that causes rotting and premature failure of structural and non-structural elements.
Source: The Canadian Association of Home and Property Inspectors