There’s a reason contractors get called in to “finish” or “fix” a DIY project. Most homeowners mean well, but some lessons you only learn by doing (or, honestly, by messing it up first). After years of fixing everything from sagging floors to lumpy drywall, here are the top mistakes I see—and how to avoid them.
1. Underestimating Waterproofing (And Overestimating YouTube)
Waterproofing is one thing you can’t fake. If you skip the proper membrane, use the wrong backer board, or just “wing it” with a quick fix you found online, you’re setting yourself up for a soggy, expensive disaster. Trust me—no video can give you the hands-on skill it takes to get a bathroom or shower waterproofed correctly. And that’s before we even get to tiling.
2. The “Weekend” Project That Eats Up a Month
It always looks easy on YouTube, right? Reality check: the pros make it look fast because they have years of practice. Homeowners often underestimate just how long something like drywall, mudding, or tiling actually takes. If you’ve never done it, expect results that look perfect—from three feet away. Up close, well… not so much.Here’s a trick: use materials that are meant to have some texture or irregularity, like rough tiles or Venetian plaster. It hides the imperfections better, and you’ll be a lot happier with the result. It does not have to be perfect to look perfect.
3. The Dangers of Knocking Down Walls (Just Don’t)
Maybe the most jaw-dropping mistake I’ve seen—more than once!—is a homeowner taking out a wall because “it just seemed in the way.” Suddenly, the house is sagging in the middle, and I get the emergency call. Before you even think about removing a wall, talk to a pro. There’s a good chance it’s holding up something important (like, you know, your roof).
4. Finish Strong—Start With Preparation
If you want a project to look good, don’t rush the prep. Clean, measure, use the right primer or underlayment. I promise: every step you try to shortcut at the start is going to haunt you at the end. Take your time—fixing mistakes after the fact is twice the work.
5. Don’t Fear the Roll—Be Inspired by Success
Not all DIY stories end in disaster! I once saw a homeowner refinish all her kitchen cabinets with just a roller. It took her two weeks, but it came out looking like a spray finish—absolutely fantastic. She said she watched a bunch of videos, took her time, and focused on prep between coats. Sometimes, the slow and steady approach really pays off.
6. Know When to Call a Pro
Some things are just better left to professionals (or at least deserve a consult):
- Removing or moving walls
- Major plumbing work
- Drywall if you want a showroom finish
- Tile in bathrooms or showers
Do your research, watch all the tutorials you want, but don’t be afraid to call for help before it’s a total rebuild job.
Bottom Line: What Every DIYer Needs to Remember
DIY projects can be deeply rewarding, both financially and creatively—but only when approached with realistic expectations and solid preparation. Many of the most costly and stressful mistakes happen when homeowners rush through steps, skip proper research, or take on projects beyond their current skill level.
Instead of aiming for perfection, aim for progress. Choose materials that are forgiving, take your time with each phase, and never underestimate the importance of prep work. And when something feels over your head—whether it’s knocking down a wall or waterproofing a bathroom—it’s perfectly okay (and often smart) to call in a pro. A quick consult could save you from an expensive do-over later.
At the end of the day, the best DIY results come from honesty—about your tools, your time, and your know-how. Build with care, and you’ll build with pride.
Common Questions
Skipping proper waterproofing is a major issue. Many DIYers rely too heavily on online videos and overlook critical steps like installing the right backer board or membrane, leading to water damage.
Many homeowners underestimate the time needed because pros make it look easy. Tasks like drywall or tiling require experience and often end up taking weeks instead of a weekend.
Not without consulting a professional first. Some walls are load-bearing, and removing them can compromise the structure of your home—potentially causing it to sag or worse.
Extremely important. Rushing or skipping prep work like cleaning, measuring, or priming often leads to poor results and double the effort later on.
Yes, with patience and the right materials. Using finishes that allow some texture, like Venetian plaster or rough tile, can help hide imperfections and improve the final look.
Avoid major plumbing, moving walls, bathroom tiling, and drywall if you want a showroom-quality finish. These are best left to professionals or at least deserve a consultation.
Absolutely! One homeowner successfully refinished her kitchen cabinets using just a roller. By focusing on prep and taking her time, she achieved results that looked like a professional spray finish.
About the Author:
Karolis Senkus is the owner of SenkusBuild, a remodeling contractor in the northwest Chicago suburbs. He’s seen it all, fixed most of it, and believes the best DIY projects start with good prep—and honest expectations.
