Finished basements with foundation problems
Repair cost: $5,000 to $100,000
Finished basements can sometimes hide serious foundation problems and raise repair costs because you'll likely have to rip out the finish work to fix things.
"If you've got a basement finished with, say, knotty pine, you won't even see any foundation problems," Salomon says. "They'll all be hidden."
Fortunately, a good home inspector can spot cracks or uneven floors elsewhere in the house and realize that they point to foundation flaws.
Remediating the problem generally involves adding what's called a "pier system" to the foundation, which can cost $5,000 and up -- sometimes way up.
Repair cost: $100 to $1,500 per room
Two potentially expensive electrical problems are degraded "knob-and-tube" wiring and the use of aluminum wires with incorrect switches and outlets.
Knob-and-tube wiring is an old electrical system seen mostly in houses built before 1930. "After 80 years, the insulation has often become frail -- creating a potential fire hazard," Salomon says.
Knob-and-tube wiring also predated modern insulation and can get warm with use, creating an additional fire hazard in houses where homeowners have put insulation over it without realizing the risk.
Upgrading knob-and-tube wiring can cost $1,000 to $1,500 per room -- mostly because you often have to cut into walls to replace it, then refinish affected surfaces afterward, Salomon says.
Aluminum wiring can cause problems when it's installed with the wrong light switches or electrical outlets, a fairly common occurrence.
Salomon says installers sometimes mixed aluminum wires with switches and outlets designed for copper wiring only, opening the door to oxidation that can create fire hazards. Cost to fix: About $100 per room.