Bill Loden, president of the American Society of Home Inspectors (ASHI), has been inspecting homes for the past 20 years. But he says some home headaches simply don’t reveal themselves during a standard inspection – and some are outside an inspector’s scope.

“There are things homeowners think we can do, but we can’t,” he explained. “And honestly, most people don’t want to pay for [a specialist].”

To get the most value from your home inspection, it’s important to know a few things even professionals might miss.

1. Partially blocked or damaged sewer lines

Some house problems don’t show up overnight, and a partially blocked or damaged sewer line often falls in this camp.

“We’ll run water through the fixtures, but we’re there for a limited time,” Loden explained. “Two to four hours might not be long enough for the problem to reveal itself.”

Inspectors will likely determine the type of drain pipe used and estimate its age. They may also look for trees or stumps near the sewer pipe that could cause damage. However, sewer-pipe scoping (sending a camera down the line) isn’t typically included in a standard inspection.

2. Failing HVAC equipment

Similar to damaged sewer lines, HVAC equipment can be fine one day and stop working the next.

“If I check an air conditioner when temperatures are moderate, it can seem fine,” Loden explained. “But under stress, when temperatures shoot up, it can fail.”

Loden says inspectors can bring an HVAC contractor with them for the inspection, but typically it’s not worth the investment when you compare the cost of buying a new unit.

“It will cost anywhere from $3,000 to $5,000 [to hire a contractor] and could take two to three days to complete,” he said.

3. Cracked heat exchanger

An area where you may want to pay for an HVAC contractor: an old furnace.

“In my area in Alabama, we have a lot of package units [furnace/air conditioner combined] that sit outside. It’s not part of the standard inspection to examine the heat exchanger, but a lot of them develop cracks that can allow the indoor air to mix with combustion air that has carbon monoxide,” he explained. “You don’t want that in the house.”

Loden recommends having an HVAC contractor examine the heat exchanger if a furnace is more than 10 years old.

“If the HVAC contractor does find such a crack, by law they have to replace it before the furnace can be used again,” he said.

4. Electrical problems

Loden says the best way to think about a standard home inspection is a “visual inspection,” because when it comes to electrical issues, inspectors can’t always determine the problem’s source.

“If I find a receptacle that doesn’t have ground, I know it’s disconnected somewhere, but I don’t know where,” he said. “You’re going to have to have an electrician find the disconnect in the system.”

5. Structural issues

Is the roof sagging, or is it part of your new home’s architectural style? Luckily, a home inspector should be able to tell.

“All roofs – at least wood roofs – have some inconsistencies. A home inspector knows what’s normal and what’s not,” Loden said.

However, when it comes to identifying how bad a problem is or how much it’s going to cost to repair, an inspector isn’t the right person to ask.

“Because we’re not licensed structural engineers, we’ll refer homeowners to one,” Loden said.

6. Leaks

Leaks may not be there one day and show up the next. For this reason, inspectors might not initially detect them.

“A lot of times we go into vacated homes,” Loden explained. “With the plumbing system not being used on a daily basis, any leaks may have dried up. And it may take a couple days after the water is turned on for the leaks to make themselves visible.”

Loden recalls his own home inspection when it was pouring rain. “The roof was not leaking when I moved in, but six weeks later it was,” he said. “A home inspection is not a guarantee that the house won’t have problems in the future.”

He says that the best thing you can do is carefully check the drains in cabinets before and during your move.

“A lot of times homeowners place belongings under there. Sometimes they’ll pack them up after the inspection and bump the drain traps, causing them to start leaking. The same thing can happen when you move in.”

At the end of the day, the key is to take precautions and make sure you find a certified inspector who has been inspecting in your area for a long time.

“They learn where failures are likely to occur,” Loden said.

Top featured image from Shutterstock.

Related:

• The Huge Risk Home Buyers Take When They Waive Inspections
• Asking These 6 Questions Can Save You Money When Buying New Construction
• How to Negotiate Repairs After a Home Inspection

Originally published September 5, 2014.