TV shows make home renovations look fast and easy. The transformations are incredible, the homeowners are happy and it only takes 30 minutes to work through all the stages of demolition, inspections, modifications and finishing touches.

Renovating in real life is much more challenging. Instead of an entire work crew hidden behind the camera, there’s just you — and anyone you choose to hire. Many DIYers start house projects on their own to save costs. However, how do you know if a project is over your head?

Sometimes, hiring a professional is cheaper than the potential cost of a failed reno. Some house projects are dangerous and require an expert to meet safety and legal requirements. Many homeowners jump into projects and realize they’ve taken on too much. Here are nine home renovations you should never attempt to complete on your own.

1.   Cut Down Trees

If you have a large tree on your property, you may be tempted to cut it down yourself. You might be able to pull it off if you have experience working in this industry and the right tools. However, most of the time, it’s a very bad idea.

Even professionals work in teams to complete a project like this. Cutting down trees involves heavy weights and gravity — a combination that can quickly become dangerous without the proper forethought. Hire an expert and you won’t have to worry about something going wrong.

2.   Handle Pesky “Neighbors”

Many homeowners deal with pesky neighbors — pests like raccoons, termites and ants that destroy their property. Although it is possible to drive these invaders away on your own, it can also prolong the process and lead to more property damage. Larger animals can be dangerous and difficult to handle.

Think carefully about how you want to wage war on the pests in your home. Hiring a professional may be worth the cost if they’re causing serious damage. If you choose to engage with them yourself, go above and beyond to stay safe. A trip to the emergency room isn’t part of your renovation budget.

3.   Remove a Wall

You’ve probably heard the term “load-bearing wall” before. Load-bearing walls are part of your house’s internal structure. They’re carefully placed to distribute the weight of your home’s upper stories so everything stays stable and secure. Unfortunately, they’re not always easy to recognize.

Before you remove a wall, it’s worthwhile to have a professional evaluate its importance to the home. If it’s a simple room divider, you can knock it down. Tearing down a load-bearing wall without installing a structural replacement will make your house unsafe.

4.   Work on HVAC

Some HVAC units are meant to be installed and repaired by homeowners. However, working on other systems can mean exposing yourself to high levels of electricity or dangerous gases. There’s also a potential risk of violating your system’s protective warranty by working on the unit yourself.

It’s a good idea to bring in a professional whenever there’s electricity involved. HVAC units are complicated and expensive, so it makes sense to treat them with care. Research your specific unit and decide whether you feel equipped to work on it safely.

5.   Install a New Roof

Most types of roofing only last for a few decades before they need to be replaced. Because replacements are so expensive, it may be tempting to do the work yourself. You might save some money in the short term, but there are several reasons why doing roof repair alone is a bad idea.

Working on a roof is dangerous, especially if it has a steep slope. The inside of your home must be completely sealed off and the new roof installed properly to avoid leaks later. This also takes a lot of time. Hiring professionals will ensure you get your money’s worth.

6.   Add an Electrical Outlet

Many old homes have reduced electrical capacity. However, adding an electrical outlet yourself is never a good idea — in fact, it can end very badly. Too much electricity at once can overload your outlets and cause a fire. It’s possible to lose your house from a wiring issue.

Electrical wiring diagrams are so complicated that people go to school to learn about them. Unless you’re an expert, trying to change your home’s electricity yourself is not worth any money you could save. A professional will ensure the job is done with minimal worry and safety issues.

7.   Pump Septic System

In addition to being gross, this process is difficult and takes a lot of hard labor. Because this maintenance task deals with waste, it’s also regulated by the EPA. A professional contractor will have the right equipment and know how to dispose of everything without causing environmental damage.

Although this isn’t technically a renovation, it can feel like one. Hiring someone to pump your septic system is relatively cheap. It’s 100% worth saving yourself the trouble and outsourcing this project.

8.   Alter Major Plumbing

If you have a small leak under your sink, you may be able to fix it yourself. However, it’s always best to have a professional lead a major plumbing remodel. Leaking pipes can destroy your home from the inside out. Water damage is one of the worst things to deal with and saving initial costs is not worth the risk.

Before starting a plumbing project, ask yourself how complicated it will be. Make sure you do your research and are certain you can handle everything yourself. For example, copper piping has to be sealed with a welder. It won’t be fun to wait on a professional after your plumbing no longer works.

9.   Repair the Foundation

Your home’s foundation holds everything together. Over time, various issues will affect the integrity of your whole house and damage your property value. Don’t waste time if you find cracks and suspect foundation problems.

Call a professional to investigate and help you fix things. The earlier you catch foundation issues, the less expensive it will be to repair the damage. Some things are worth weighing the pros and cons — this problem is essential enough that you should start with an intensive, professional solution.

Consider the Risks

Sometimes, doing a home renovation yourself is worth the savings. However, there are some situations where DIYing a home project with no experience is a very bad idea. Experimenting on your home isn’t a fun way to learn about electrical loads or how to properly seal a roof.

There’s more than one cost when you renovate your home. You have to consider time, energy and stress, as well as finances. Renovations can take a really long time if you do them yourself. Mistakes can mean you spend more money than hiring a professional to begin with.

Before you start any home renovation project, take stock of your resources and the best way to use them. Consider whether a project is dangerous and how much knowledge you need to do it successfully. For these nine renovation projects, it’s always best to call a professional.