A guide to common home inspection pitfalls that could jeopardize your property sale or purchase.
9 Things That Fail a Home Inspection
Updated on Sep. 12, 2024
Home Inspections Uncover Critical Issues
A home inspection is a visual check of a dwelling’s major systems and structures, inside and out. While home inspectors don’t technically assign a “pass” or “fail” grade to a home, they do present their findings to the home buyer, who may withdraw an offer if there are red flags.
The following are nine of the most concerning and expensive-to-fix issues that may come up during a home inspection. To compile this list, I talked with two industry experts — Reuben Saltzman from Structure Tech and Ted Towne from T3 Home Inspections.
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Foundation Problems
A problematic foundation can have bowing walls, horizontal cracks or sinking corners. While these may be due to age or improper installation, Saltzman finds soil and drainage issues are often to blame.
“If you have a bunch of water that pools around the foundation, that can exert a tremendous amount of pressure on the foundation,” Saltzman says. “You end up with walls bowing in, and you end up with cracks.”
Adds Towne: “Horizontal cracks are a big red flag. There’s something structurally not right if you’re getting that type of crack or that type of movement.”
While Saltzman admits it’s unusual to have to entirely rebuild a foundation, even specialized reinforcements and repairs can cost in the tens of thousands of dollars.
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Structural Issues
Another major problem relates to anything affecting the structural integrity of the home. This can include the foundation, roof supports, floor, ceiling joists and walls.
Signs of structural issues can include sagging rooflines; uneven floors; cracked, bowing or bulging walls; and sticking windows and doors. The cost to fix these varies, but can run from $5,000 to more than $25,000, depending on the severity.
Saltzman says broken roof trusses can be a particularly expensive structural issue to fix. These are specially designed support frames manufactured off-site.
“You can’t just get a carpenter out there to slap some wood on the outside,” Saltzman says. “It needs to be designed by the truss manufacturer.” The American Association of Home Inspectors estimates this cost at $7,400 to $21,000.
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Roof Problems
While an older roof that needs replacing can be easy to spot, even new roofs can have problems. The national average to replace aging roof shingles ranges from $10,000 to $36,000, but less obvious issues can be just as costly.
“I’ve seen quite a few roofs recently that were just installed incorrectly,” Towne says, “They either don’t have flashing or it’s not done right and is causing leaks around chimneys, or in valleys where two roof section meet.”
Roof leaks can lead to a host of secondary problems like wood rot, mold or stained ceilings.
“Also, in the case of older roofs, a lot of them weren’t supported well, and you end up with some major sag over time,” Saltzman says. “And that can even lead to broken rafters.”
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Wood-Destroying Insect Infestation
Wood-destroying insects like carpenter ants, termites and powder post beetles can cause extensive damage to a home. They bore through, nest and feed on wood fibers. Over time, they weaken major structural supports like joists, timbers, sills and wall frames.
Checking for wood-destroying insects is a separate inspection from a standard one, and usually costs $75 to $325. But it can save a home buyer from purchasing a home that needs thousands in repairs.
“That’s a really important one,” Saltzman says. “They’re a huge concern in just about every part of the country.”
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Improper Ground Drainage
If the dirt around a home slopes toward it instead of away, stormwater will collect next to the foundation. That can cause moisture problems, especially concerning in finished basements. “If you don’t have good drainage, there’s a good chance you’re going to have water coming in, which can lead to mold and mildew issues,” Saltzman says.
Fixing improper drainage requires regrading. “If you do have negative pitch, you’ll need to bring in dirt and landscaping,” Towne says. “That can get expensive depending on how much you need.” Expect costs to range from $1,000 to $5,000 to regrade around an entire home, depending on project size.
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Electrical Issues
Minor electrical issues are generally not a dealbreaker for most home buyers. But major ones, like ancient knob-and-tube wiring and aluminum wiring, can be expensive to remedy.
Lots of homes have aluminum wiring, which is not always a problem. But Saltzman says aluminum branch circuit wiring is a different story. “This includes aluminum wiring going to traditional outlets, switches and fixtures throughout the house,” he says. “That’s a major concern.”
Aluminum wires significantly expand and contract during use. These can cause wire connections to loosen over time, creating a fire risk. Your inspector will make note of this issue, but it may be wise to hire an electrician for a full assessment.
Fixing wiring issues is no picnic. “It [requires] either replacing the wiring or redoing all the connections where each wire begins and ends,” Saltzman says. The cost to rewire a 1,500-square-foot home runs $7,000 as a national average.
Knob-and-tube wiring will also require removal and rewiring of parts or all of the home.
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Plumbing Issues
Major plumbing problems, like broken sewer drains or clogged pipes, can cost thousands to fix.
Saltzman identifies old galvanized water supply and distribution pipes as a big problem if found in a home inspection. Galvanized pipes are particularly prone to clogging over time, severely restricting a home’s water flow.
At that point, replacement is the only option. This can get pricey, especially for water supply pipes. “It involves replacing all the water piping all the way out to the street, and it’s typically the homeowner’s responsibility,” Saltzman says.
Just as concerning are problems with the home’s drains. “It can be the drains inside the building, or it could be the drain going all the way out to the city sewer,” Saltzman says.
To repair or replace a main sewer line can cost $20,000 to $30,000.
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Mold
Mold develops in places with moisture, especially on porous surfaces like drywall, wood, ceiling tiles, insulation and carpet. Moisture can enter a home through roof leaks, broken plumbing or compromised siding, or from condensation build-up in places like attics and basements.
“A lot of times where I’ll see mold or mildew staining is in the attic, which is generally from bad ventilation,” Towne says. “That can get pretty pricey to remove and clean.”
Moisture problems in finished basements can also quickly spawn mold, requiring expensive removal and refinishing. “If there is mildew in a basement on wood, the wood can be cleaned,” Towne says. “If it’s on porous surfaces like drywall or insulation, that will need to be cut out, removed and replaced.”
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Environmental Hazards
Environmental hazards like asbestos, lead and radon can pose serious health risks. “Particularly of concern is vermiculite insulation in the attic,” Saltzman says.
Vermiculite insulation was often used in homes built before 1990 and can contain asbestos, a known carcinogen. Removal costs average $10,000 to $15,000.
Radon is a naturally occurring radioactive gas that can accumulate in basements. According to the Environmental Protection Agency (EPA), radon exposure is one of the leading causes of lung cancer in non-smokers. They recommend home testing and mitigation systems, which can cost $1,000 to $2,000 to reduce, but not eliminate, radon gasses.
Lead in paint or water pipes is toxic to humans and can cause a host of major health issues that affect nearly every bodily system. Lead paint requires encapsulating or removal, while lead water pipes must be replaced to remove the risk. Both can be costly.
About the Experts
- Ted Towne owns T3 Inspections, a full-service home inspection company in Easthampton. Massachusetts. He is a licensed and insured home inspector with 10 years experience.
- Reuben Saltzman is the owner and CEO of Structure Tech, a home inspection company in St. Louis Park, Minnesota.
