A  do-it-yourself project  can be an empowering way to save money, provided you know what you're doing. But even one slip of the proverbial hammer could put a strain on your back or your bank account. Sometimes, it's best to put safety first and call a professional. Here are four types of home improvement projects that are best left to the experts.

1. Plumbing or electrical projects --  There's a reason these are skilled trades. Both systems are complex, no matter how straightforward a repair may initially appear. Even small leaks can cause serious water damage, and faulty electrical wiring can lead to a house fire. Don't risk flooding or electric shock. Call a plumber or  hire an electrician  to make sure these jobs are done right the first time.

2. Renovations with possible code violations --  Structural changes require a licensed contractor. Not only can shoddy craftsmanship severely affect your home's value, but it can also put your family in danger. Accidentally remove a load-bearing wall, for example, and you could collapse the entire room. Why take the risk?

3. Repairs involving heights --  More than  130,000 ladder-related injuries  are treated in emergency rooms each year. Whether you're looking at a roof repair or trimming a tree, consider calling a professional before attempting to complete the job yourself.

4. Time-sensitive projects --  Weigh your work and family commitments before embarking on a home improvement project. Even if you're confident in your abilities, the added pressure of a tight deadline can lead to unnecessary and often dangerous mistakes.

Remember, just because a DIY project looks simple doesn't necessarily mean it's safe. When in doubt, err on the side of caution and call a professional.