How to Fix a Small Plaster Crack

Overview

Small plaster cracks can be repaired easily. This guide covers fixing hairline cracks in plaster.

Step-by-Step Fix

1. Carefully use a utility knife or a V-shaped crack opener to gently widen the crack slightly, creating a small, clean V-groove. This provides a better surface for the filler to adhere to and prevents it from simply sitting on top of the old plaster. Ensure no loose plaster fragments remain within the widened crack before proceeding.
2. Using a flexible filling knife or putty knife, firmly press a small amount of ready-mixed plaster filler into the widened crack, ensuring it's completely filled. Scrape off any excess filler from the surrounding wall surface, leaving the repair as flush as possible with the existing plasterwork.
3. Allow the plaster filler to dry completely according to the manufacturer's instructions, which can typically be found on the filler's packaging. Drying times vary, but always ensure the filler is hard to the touch and no longer feels damp or pliable before moving to the next stage.
4. Once the filler is fully dry, gently sand the repaired area using fine-grit sandpaper (e.g., 120-180 grit) to achieve a smooth, seamless finish that blends with the surrounding wall. Regularly run your hand over the sanded area to check for any bumps or depressions, continuing to sand lightly until the surface is perfectly flush.
5. Apply a coat of plaster primer or an appropriate undercoat to the repaired patch, following the product's instructions, to seal the filler and provide a consistent base for painting. Once the primer is dry, you can then apply your chosen emulsion paint, matching it to the existing wall colour for a flawless finish.

Common Symptoms & Diagnostic Resolutions

Review the common error codes and operating symptoms below to quickly identify the root cause of the fault before ordering replacement parts.

Frequently Asked Questions