The home improvement industry consists of companies that repair, alter, upgrade or improve homes. Home improvements can include anything from caulking and weather stripping to installing a smart thermostat or resurfacing a kitchen. Some states have specific definitions for what qualifies as a home improvement, such as adding an addition or building onto a structure that is already there.

Some homeowners are planning projects to make their home more attractive or functional, while others are looking for a return on investment when they sell. However, the type of project that will make the biggest difference in resale value may surprise you.

Overhauling surfaces underfoot and overhead was the most popular home improvement in 2017, with 5.2 million Americans replacing carpeting, flooring, paneling or ceiling tiles. In many cases, those renovations provide a solid return on the investment.

Other projects that have a higher risk of reducing resale value include custom upgrades that cater to an individual taste or lifestyle. For example, a home recording studio or in-home spa aren’t likely to appeal to a broad range of potential buyers.

It’s important to choose contractors carefully and understand what you’re getting into before undertaking any home improvement work. The state of Maryland requires that all contracts for home improvement services be in writing and signed by the contractor or business before any work begins or any money is paid. Typically, the contract should have the contractor’s name, address and MHIC license number preprinted on it. It’s also a good idea to ask the contractor for references and check their license status with MHIC before hiring them.