How to Stop Drywall Inside Corners From Cracking
Whether drywall cracks are caused by shrinking framing lumber or other structural issues, installing flexible cornerbeads to let joints move is often the easiest solution.
Three years ago, I built a house, and every year, the inside drywall corners crack in several rooms. Is there anything I can do to stop this problem from happening?
Ed Wuermser, Dallas, TX
Myron R. Ferguson (www.thatdrywallguy.com), author of Drywall (The Taunton Press, 2012), replies: Cracks in inside corners often indicate structural movement. This movement might be caused by swelling or shrinking of framing lumber due to seasonal changes, or it might indicate a more significant structural problem. If you’ve eliminated the latter possibility, there are some things you can do to fix the cracks.
Vinyl or PVC tapes made for seams and inside corners are strong, but they often pop loose if there is structural movement. Don’t use these products unless you’re sure the corner is stable.
In situations like yours, you’ll have the most success in making a joint resistant to cracking by letting it move. The only thing I have found that works is an expansion-joint type product. I have had great success with Magic Corner from Trim-Tex (www.trim-tex.com). It works on inside corners at any angle, and it also can be used to fix cracks.
To repair an inside corner, fully remove the existing tape, and replace it with Magic Corner. Tape the joint as you normally would, leaving the rubber center free of mud. Any movement will be absorbed by the rubber center, which flexes and stretches. The only bad thing is that you see the rubber center as a slight recess in the surface. This slightly indented line is much better than a crack.