What should you look for when touring a house? That’s what you’ll learn on HGTV’s new show “Home Inspector Joe,” where Joe Mazza checks out homes to reveal hidden dangers that must be fixed.

In the Season 1 episode “From Rot to Riches,” Mazza meets Mathieu and Giovanna, new parents excited to buy their first home in Mamaroneck, NY. Even with an $800,000 budget, these two haven’t had any luck in this competitive market, so they’ve realized their  best option is to buy a fixer-upper. Still, this can be risky, so that’s where Mazza and his go-to designer, Noel Gatts, come in.

“My goal here is to tell you exactly what’s wrong with this house,” Mazza tells the couple.

“And I’m going to point out what’s right with it,” Gatts adds.

Together, Mazza and Gatts help these buyers make their old house both safe and beautiful. Read on to find out which five red flags they find, how much they cost to fix, plus one low-cost cosmetic makeover you can do even if all your money’s gone to repairing serious problems.

One of the first things Mazza likes to check on a home is the roof, since a new one costs a ton of money. And unfortunately, this one’s on its last legs.

“The roofing system, it’s weathered, it’s aged,” Mazza says when they first tour the house. “It’s definitely past its typical life expectancy. Look at the shingles that are flipped up on the front. They’re broken. You have missing shingles on that side—they’re cracked.”

Worse yet, the roof has been letting in rain, causing water damage to the living room.

The new roof ends up costing $16,000, but Mazza points out that this expense is necessary.

“It had to be done, and it’s worth every penny to stop the water from getting in the house,” he says.

Plus, the roof’s darker gray color adds some dimension, making the exterior look more modern. While no new homeowner wants to dish out $16,000 on a new roof, it’s clear this was money well-spent.

Watch: Behind the Scenes of ‘Selling the Hamptons’ With Bianca D’Alessio

Mathieu and Giovanna are already spending a fortune on a new roof, but Mazza has more bad news for them during the home inspection: They’ll need new siding, too.

“The house obviously has been neglected for a long time,” Mazza says. “Exterior siding, as we can all see, is super, super old.”

He points to a hole by the roof, which could be letting in more water. Plus, this hole is big enough for an animal to fit through.

Mazza helps remove the cedar shakes and replaces them with $15,000 in new siding. It’s another pricey fix but one that, like the roof, is worth the money.

When the siding is done, the home looks practically new. And the best part? This family won’t have any unexpected furry visitors.

Even after replacing the roof and the siding, this exterior still isn’t finished. Right away, Mazza knows the driveway needs to be replaced.

“This whole thing is shot. There’s no sugarcoating that. It’s got to get done,” he says.

The new driveway costs $3,500, but it’s a smart upgrade that will make the exterior of the house a lot safer.

“When you have a driveway that was torn up like this one here, water’s going to pool there, ice is going to build up, someone’s going to walk out of the house, slip, fall, and get hurt,” Mazza says. “This new driveway that’s going in right now, this is going to drain away from the home. It’s going to look great. It’s not going to be a tripping hazard anymore.”

Mazza knows that it’s important to check pipes in an old house. Of course, homeowners will want to replace lead pipes, but not as many people know to check for galvanized pipes, which are pipes that have been dipped in a zinc coating to prevent exterior corrosion. These pipes might be protected on the outside, but they have a lot of problems inside.

“Galvanized piping corrodes from the inside out, and you can see all the connection points—they’re all corroded,” Mazza says. When he opens up a pipe, the inside shows how decayed and clogged it is.

New pipes cost only $1,500, but it’s an important fix.

“This clogging will not happen once we’re done,” Mazza says. “We’re going to put PVC piping in, the corrosion will stop, and they can have the proper drainage system in their house that they’re supposed to have.”

Another big problem to look out for is mold, and unfortunately, Mazza finds a lot of it in Mathieu and Giovanna’s house.

“This stuff right here is extremely dangerous,” Mazza says, showing these homeowners the basement wall. “Anything like this in the house, it’s over!”

Mazza has the mold remediated by experts, explaining that removing mold is not something homeowners should try to do on their own.

“This is not a DIY project whatsoever,” he says. “If you’re married to one of these weekend warriors that think they can tackle a mold issue, shake your head, do your homework, and call a professional to have it taken care of the right way.”

With all these expensive problems, it’s no wonder Mazza spends nearly every cent of these homebuyers’ budget to make repairs. So at the end of the project, Gatts realizes that it’s up to her to find cheap design solutions that Mathieu and Giovanna will love. One spot she sees opportunity is the fireplace.

“Our original goal was that we could afford some really beautiful tile, maybe from Italy or something cool,” Gatts says. “But we can’t afford that right now, which is fine. We still have a way of making this unique. So we’re going to use paint, which is always the most affordable way to make something exciting.”

Gatts uses stencils to create what looks like a tile hearth. It’s a smart upgrade that makes the fireplace look custom. It goes to show that an old house may need a lot of expensive fixes, and while it’s important to look for features that need repair, it’s also important to look for fun, creative potential.

Jillian Pretzel is a Southern California writer who covers lifestyle, relationships, home, and money management.