2 helpful guides for repairing bricks and mortar

August 14, 2015

If you see issues with your brick walls, diagnose the problem and assess whether you could fix it yourself or should turn to a professional. Here are a few tips and two helpful guides to help you out.

  • Loose, crumbly and cracked mortar: Seeing this means that mortar has deteriorated and bricks need repointing. This job is fairly easy but can be time consuming.
  • Chipping or flaking bricks: Your bricks are softer inside than outside and deteriorate as they weather. You should replace badly weathered bricks as soon as possible, which is a fairly easy but time intensive job.
  • Cracks in walls: Hairline cracks in you walls are usually harmless. But, zigzagging cracks along joints are more serious and may indicate that the foundation of your home are gradually settling. Repair work on this sort of problem ranges from easy to difficult, depending on the cause.

Here's how to repoint and how to replace bricks.

2 helpful guides for repairing bricks and mortar

1. Repointing bricks

What you will need

  • Safety glasses
  • Gloves
  • Old screwdriver
  • Club hammer
  • Plugging chisel
  • Stiff-bristled brush
  • Mixing container or wheelbarrow
  • Mortar mix (or masonry cement and bricklayer's sand)
  • Water
  • Trowel
  • Pointing tool
  • Rake with wheels
  • Hand brush
  • Stiff whisk broom (if required)

1. Scrape it out

  • Put on your safety glasses and gloves, then use an old screwdriver to remove any loose, soft mortar to a depth of 2.5 centimetres (1 inch).
  • For more solid mortar, use a hammer and plugging chisel, being careful not to chip the edges of the bricks.
  • Carefully clear all chips and dust from the joints using a stiff-bristled brush.

2. Mix the mortar

  • To make the new mortar, dry-mix four parts cement with one part sand then add water and a plasticizer to make a paste that is stiff, but not crumbly.
  • Ask your cement supplier for advice on how to match the colour of the old mortar, so your repair work isn't noticeable.

3. Push it in

  • Once the mortar is the right consistency, scoop some up on your trowel and push the mortar into the joints with your pointing tool, making sure the joints are completely filled.
  • Avoid getting mortar onto the face of the bricks so that you won't have to clean them off later.

4. Rake the mortar

  • Once the mortar is hard enough so that you can leave a thumbprint in it (also called thumbprint-hard), run your rake with wheels over the joints to smooth and shape them so they match the existing joints.
  • Smooth out the areas where old jointing meets new jointing with a stiff whisk broom or hand brush.

5. Brush it down

  • Sweep the joints with a brush after the mortar begins to stiffen.
  • This will help you match the texture of the old jointing to the new jointing's texture.
  • It will also remove any loose material and help to prevent shrinkage in the new mortar.

2. Replacing a damaged brick

1. Remove the mortar 

  • To replace a damaged brick, first use a plugging chisel to chip out the the mortar around it.
  • Be careful not to chip the surrounding bricks.

2. Get it out

  • Next, use a cold chisel or bolster to break up the brick. Pull out all the pieces.

3. Refill it

  • Dampen the opening.
  • Spread mortar on the base of the cavity and on the topside and ends of a dampened new brick.
  • Insert the new brick and tidy up the mortar as necessary.

Follow these guides the next time you're repairing your brick walls and your job should go that much smoother.

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