How To Fill Cracks In Wall. Another lesson in the preparation process from barry mason. If cracks in drywall or plaster are deeper than a 1/4 inch, you will have better success if you first fill the the crevice with a filler compound prior to taping with joint compound.
When it has dried a little, score the plaster with a nail, as shown at right.
Sometimes, though, cracks in walls signify a larger problem. How to fix fine cracks, large gaps, holes and wall chases. 2 the type of filler you use will depend on the size. Even if you're 5'2″ and have to stand on a chair while they actually make stuff specifically for filling in cracks in plaster walls (doesn't shrink, etc).