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How to fill a crack in a wall

Picture of a yellow wall with a ladder and paint cans
Learn how to fill in cracks with our simple guide

Cracks in internal walls are a common DIY challenge but easily fixed. Just follow our simple step-by-step guide for help.

Here’s what you need to get started:

  • All-purpose filler
  • Sandpaper sheets
  • Protective floor sheets

Disclaimer: If the crack in your wall is thicker than a 10p coin (3mm), visible internally, externally, and wider at the top than the bottom, you should seek professional help as your house may have subsided.

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Step 1: Prepare the area

Start by moving any furniture away from the wall and putting down a protective floor sheet.

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Step 2: Filling the gap

A picture of somone placing filler into a crack in a wall
Fill the crack in your wall with a filler and a spreader

Fill the crack in the wall using a filler and a spreader. You can use either a plastic or metal spreader. Push the filler into the crack making sure to spread it evenly along the crack.

Types of fillers:

  • Interior filler: A general-purpose filler that comes ready-mixed or as a powder to mix with water
  • Fine-surface filler: An extra smooth filler for minor cracks and surface imperfections
  • Deep-repair filler: A ready-mixed lightweight filler for holes up to 20mm deep
  • Fast-setting filler: This filler sets in 10-20 minutes
  • Flexible acrylic fillers: Used for gaps between plaster and woodwork
  • Foam filler: Used for large holes or gaps.
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Step 3: Finishing touches

A picture of someone using a fine sandpaper on the wall
Sand your wall for a smooth finish

For a smooth finish lightly sand; the area with a fine sandpaper once the filler is dry. Then repaint the wall.