Easy DIY Repair Guide: How to Fix Cracks in Plaster Walls
2. Drill pilot holes down into the wood lath along both sides of the crack. Secure a 1⁄8 in (3.2 mm) masonry bit into your drill and drive a hole into the plaster about 1 in (2.5 cm) from the crack. Feel for the resistance to increase when you push through the plaster and into the wood lath.