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We recently wrote a project on how to replace single bricks. What you might not understand is why would I want to replace a single brick? We look at the causes of damage to bricks which may lead you to have to remove and replace bricks in an existing wall.

Brick is Crumbling or the Face has Blown Off

The face of a brick can crumble away due to freeze-thaw action. This is where water has got into the surface of the brick during cold weather, and has not been able to dry before the temperature drops below freezing, causing ice crystals to form within the fabric of the brick. As this ice thaws the ice crystals expand, pushing on the structure of the brick and because the pressure has nowhere else to go it ‘blows’ the face off the brick.

This can affect a single brick or a few bricks. Over time this can cause considerable damage and water will be able to get to the interior face of the brick too. Read more about freeze/thaw action and the damage it can cause.

When replacing the damaged brick, first investigate the cause of the water penetration. Is there a leaking downpipe or overflow? Is there some damage to coping stones or a roof above that is leading to the brick becoming saturated by rainwater.

Brick is Cracked

Cracks in bricks (and surrounding mortar) could be caused by settlement or subsidence. Obviously you need to deal with the underlying causes of cracked bricks, especially if subsidence is involved. However once this has been addressed you can go ahead and replace any cracked bricks using the methods we describe in our replacing a damaged brick project.

Where the brick is not cracked but the surrounding mortar is, you may want to take out a single brick, so you can hack out and replace the surrounding damaged mortar.

Removing a single brick

Removing a Single Brick

Remove a Single Brick for Inspection

If you have damp on interior walls and you have ruled out all the other causes of damp you may need to check if there is a faulty wall-tie or a quantity of builders’ rubble left in the wall cavity. Either of these can form a bridge for moisture to breach the cavity, which allows water to soak through from outside to inside the wall.

Cavity Wall filled with Rubble

Cavity Wall filled with Rubbish

If you remove single bricks near the area affected, you can then look into the wall cavity to see what the problem is. You can use a special flexible camera to see into the cavity otherwise you may need to remove a few bricks together, to make a hole big enough so you can look at what is happening.

Once the problem is diagnosed you may need to remove a few more bricks to affect repairs, but the process is similar to removing a single brick, and replacing the bricks at the end is is exactly the same.

Old Holes

If you have changed some plumbing inside the building you may have removed an overflow pipe or soil pipe which was running through the wall. This will leave one or more holes in one or more bricks and you may decide to repair these individual bricks rather than fill the holes. Replacing the bricks will be much more visually pleasing than filling holes with mortar.

Air Bricks

You may need to remove a brick to fit an air brick and improve circulation in your property. If you want to find out more about airbricks we have a full project on the website.

Stained Bricks

It is possible to clean stained bricks but you might feel that the effort involved is not worth the final result. This is especially likely where the brick is discoloured due to long-term exposure to running water, where you may be concerned about the integrity of the brick, as well as the aesthetics of it.

We have further articles on cleaning bricks stained by efflorescence, and if the damage needs treating with Muric Acid find out how to do this safely on our cleaning stained bricks project.

New bricks can take a while to weather so that they look like the rest of the wall, but you can help the process along using weathering tint, which we featured in an earlier blog post.


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