Absolutely, taping joints before skimming is like laying a foundation before building a house-skip it, and you'll end up with cracks and uneven surfaces. Here's why: when you're skimming (applying a thin coat of plaster or joint compound to smooth walls), the seams between drywall panels or plasterboards are weak points. Without tape, the skim coat can't bridge the gap properly, and over time, temperature changes or wall movement will make those seams pop, leaving ugly lines that ruin the finish.
Think of it as wrapping a present: if you don't tape the edges of the wrapping paper, it'll come apart. Taping joints works the same way. First, you lay paper or mesh tape over the seam, pressing it into a thin layer of joint compound to hold it in place. This tape acts as a reinforcement, distributing stress across the seam so the skim coat stays intact. Then, when you apply the skim coat, it bonds to both the tape and the wall, creating a seamless surface.
Pro tip: Make sure the tape is centered on the joint and smooth out any bubbles with a taping knife-bubbles can cause the skim coat to crack later. And don't skimp on the initial layer of compound under the tape; it needs to seal the tape to the wall like glue. Do this step right, and your skimmed walls will stay smooth and crack-free for years, looking like they were done by a pro.
