Many people delay hiring contractors for home repairs because they think that they can complete the work for less. While this may be true, there are some jobs that absolutely benefit from the help of a professional. General contractors earn anywhere from 10 to 25 percent of the job cost, according to WSJ.com. Some contractors don’t want to inherit botched repair jobs from you, and may even charge more to fix your mistakes. Additionally, you may pay more in the end if you DIY, factoring in time and effort. While smaller projects can be accomplished yourself, leave these four projects to the pros.

1. Don’t DIY paint that older home: Homes built before 1978 may contain lead paint. When you remodel your home or scrape off that old paint, you create lead dust and lead chips that pose a health risk. The Environmental Protection Agency requires that you have a professional remove lead paint, and provides information on finding professionals in your area. Find a certified contractor to assess your home’s risk of lead paint and remove the paint.

2. Stay off the roof: If you’ve done some home repair projects, you may have enough confidence to climb up on that roof and make repairs. Barrett Roofing Services advises homeowners against getting overconfident with roof repair and suggests hiring a contractor to save time and get the job completes in hours, not days. While you might climb up on the roof and nail down those loose shingles, leave the hard work to the pros. If you do plan to tackle roof repair, look for rental companies that offer lifts, such as sunbeltrentals.com. This way, you can load your tools and supplies onto the lift and enjoy safe and simple access to the roof.

3. Don’t Tackle That Deck Job: There’s a good reason you might want to leave that deck to a contractor: Decks require ample support underneath, and a deck built without the proper support can be vulnerable to sagging. A contractor will get the job done better and faster that you can, and knows how to accommodate the quirks of your particular dwelling. If you need to nail down or replace some loose boards, go for it. You’re probably better off leaving the deck building to a pro.

4. Find someone for foundation repair: If your home is settling and your crawlspace foundation has started to sag in the middle, you may be able to fix it yourself, writes Edwin Moore. This requires you to prop up the middle of the foundation. However, if your crawlspace foundation is sagging around the perimeter, not the middle, you’re better off hiring a pro because you do not have the knowledge or expertise to prop up the walls. Moore absolutely recommends that anyone with a slab foundation hire a contractor to fix the foundation, because this requires more than DIY know-how.