4 DIY Home Improvement Mistakes to Avoid, According to a Professional

Taking on home improvement projects can be a rewarding way to save money, learn new skills, and customize your space. While many upgrades are well within the capabilities of an experienced DIYer or beginner, others require specialized knowledge, permits, and safety precautions that aren't always obvious, and mistakes can lead to costly repairs, structural damage, or even serious safety hazards. We spoke with an expert to determine which mistakes homeowners make when attempting DIY home projects—and when it's time to call a professional.

Installing Shower Tile

Updating bathroom tile may seem like a straightforward DIY project, especially for handy homeowners. However, many people don't realize that tile alone doesn't keep water out. A properly installed waterproofing system protects the structure behind the tile, says Micaela Quinton, director of design at Copper Sky Design + Remodel.

"Improper shower waterproofing can lead to hidden leaks, mold growth, rotted framing, and water damage that spreads into adjacent rooms or lower levels before anyone realizes there is a problem," Quinton explains. "Someone who has successfully installed a kitchen backsplash may assume shower tile is similar, but it is a much more technical process."

When to Call a Professional

Shower tile and grout are not waterproof on their own. Over time, water can penetrate behind them, making a waterproofing system essential.

Quinton recommends hiring a professional for the waterproofing portion of the project. Homeowners who want to save money or just enjoy a DIY project can handle the tile installation themselves once the waterproofing is complete.

For experienced DIYers, several reputable waterproofing systems offer online tutorials. If you choose to install one yourself, use products from a single manufacturer rather than mixing components from different systems, Quinton says.

Updating Electrical Work

DIY electrical work can create serious safety hazards. According to Quinton, overloaded circuits and improper wiring are among the most common causes of electrical fires.

"Electrical mistakes don't always fail immediately, which makes them especially dangerous," she says.

Researching electrical systems can help homeowners better understand how their homes work and communicate more effectively with contractors. However, online tutorials cannot replace the training and experience required to perform electrical work safely.

When to Call a Professional

Homeowners can typically handle simple projects, such as replacing light fixtures or swapping standard switches for dimmers.

However, Quinton recommends hiring a licensed electrician for projects that involve modifying electrical panels, running new wiring, or adding circuits. These projects carry significantly higher risks and require professional expertise.

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Building or Renovating a Deck

As warmer weather arrives, many homeowners start planning outdoor upgrades. While some backyard projects are DIY-friendly, deck construction, railings, and stairs often appear simpler than they actually are.

"Common DIY deck mistakes include poor footing installation, improper attachment of the deck to the home, and unsafe railing or stair construction," Quinton says. "These issues can create major structural and safety risks."

Because decks must meet strict building codes, mistakes can lead to serious injuries for family members and guests. That's why permits and inspections play such an important role in the construction process.

When to Call a Professional

Routine deck maintenance, including staining, sealing, and painting, is well within reach for most homeowners. Experienced DIYers can also replace damaged deck boards, install skirting, or add a privacy screen wall.

However, Quinton recommends hiring a professional for any work involving structural framing, stairs, or railings. These projects typically require permits and inspections to ensure they meet local building codes.

Skipping Permits and Inspections

One of the most common home improvement mistakes is treating permits and inspections as optional, particularly for projects such as decks, porches, and new additions.

Instead of viewing them as inconveniences, think of permits and inspections as important quality-control measures, Quinton says. Building codes exist to help prevent unsafe construction practices and protect everyone who lives in the home, both now and in the future.