Making home improvements or repairs comes with the uncertainty of finding someone trustworthy to complete the projects. You’ve probably heard more than one horror story about shady contractors who do sub-standard work or take the money and run. But there are tell-tale signs that can let you a know a prospective contractor isn’t on the up-and-up. Here are some signs of contractor scams.

Showing Up Unannounced

If a contractor or repair person that you haven’t called shows up unannounced and offers to start working right away, that’s a red flag. This often happens after tornadoes, hurricanes and other natural disasters. Scammers will claim they noticed your home’s damage while doing work in the area and offer to fix it on the spot for cash. They may appear to start working, but after taking a lunch break or going to “buy supplies,” they never return, leaving you with the damage and a smaller bank account balance.

In cases of storm damage or damage from other natural causes, always file a claim with your homeowner’s insurance.

Offering to Use “Leftover” Materials

This scam is similar to the first one, but with an added “incentive” for the homeowner. A contractor — often from a driveway paving company — will knock on your door and tell you they can repave your driveway for cheap because they have leftover materials from doing other jobs in the neighborhood. Even if this if this seems true, you have no way of knowing if they’re legitimate or if they do quality work. It’s best to not engage with any tradespeople who show up without you calling them first.

Getting Started Without a Contract

You and your contractor discuss the work to be done, they even suggest changes and upgrades you haven’t thought of. You’re so excited by the possibilities they offer to get to work right away; the paperwork can wait, right? Wrong! When working with a contractor, you want a contract that spells out everything, including the smallest details. That way, you are both clear on the expected outcomes. Verbal agreements can lead to miscommunication and unmet expectations, or worse. Ultimately, if the work isn’t completed to your satisfaction, you won’t have any legal recourse without a written contract.

Skirting Licensing or Permitting Regulations

If you’re working with a limited budget, it can be tempting to cut corners by working with an unlicensed contractor, or one who waves off the need for appropriate permits. But these rules exist to safeguard both the contractor and the homeowner. If your contractor doesn’t have a license, the conversation should end there. And the same goes for a licensed contractor who wants to shortcut permit regulations or who asks you to apply for a homeowner’s permit for DIYers — even though the contractor is the one doing the work. Any of these scenarios can lead to substandard work and leave you without legal options if things don’t go as planned.

Sudden Prices Increases

You’ve agreed on the price and signed a contract. Nothing could possibly go wrong, right? Even with a signed contract, you could end up paying more than you agreed upon due to “unforeseen circumstances.” This could be anything from termite damage to structural problems to design changes. That’s why your contract should include the details for change orders — essentially mini contracts within the main contract — that spell out work descriptions and prices for things that pop up as the job is in progress.

If you have doubts or want to confirm your contractor’s claim of newly discovered structural issues, you can request an opinion from a neutral third party, such as a home inspector or someone from the local or state construction authority.