House is approximately 40 years old. On a wall on a balcony the brick work appears to be crumbling. What is causing this to happen and what can be done to fix this?

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We can see both sides of the wall since it is the edge of the balcony and the other side is similar to this as well. We had a couple of tradesmen comment on this and suggested rendering it to make it watertight, but this would obviously be out of place with the rest of the brick work of the house (which is fine)

  • Where are you located? Do you get wet, cold winters where ice forms on brick? Jul 5, 2018 at 14:57
  • 1
    We're in Scotland, so we absolutely get wet, cold and dark winters
    – Fraser
    Jul 5, 2018 at 14:58
  • It’s called spalling. Google “brick spalling” and you’ll see lots of ideas about fixing your problem. Specifically, it’s lack of maintenance, (i.e.: reseal (coat) exterior, repoint mortar joints,etc.)
    – Lee Sam
    Jul 5, 2018 at 21:27
  • It looks like you may need to repoint (remove the old mortar outer layer) and stuff it back with new
    – amphibient
    Jul 5, 2018 at 22:05
  • @amphibient - Agree but this wouldn't fix the existing bricks
    – Fraser
    Jul 9, 2018 at 9:39

2 Answers 2


Water is a common destroyer of brick, even if it isn’t freezing and thawing. Water will dissolve bricks and mortar over time. Brickwork must be designed carefully to keep it reasonably dry. The next time it rains, go and look at the damaged areas of brick and see if they are getting splashed from water falling off of a roof edge or something similar. A wider picture providing more context for the location would be helpful for us.

How is the wall capped, if at all? Is water permitted to enter the wall from above? Brick walls need caps on them, wider than the wall itself, that will shed water. Water entering open joints at the top of a brick wall will ruin it quickly.

Not all brick within a batch are created equal, especially older bricks that were fired in kilns with uneven heat distribution. Some brick in the batch will be underfired, making them softer and more absorbent, and weaker in wet situations. So a brick can fail while the one sitting right next to it hangs in there just fine.

I won’t say it’s the only cause of your problem because there are many factors at work and I’m not there to witness them all, but I will say - the condition of those mortar joints is not doing that brickwork any favors at all. In a wet environment brick joints should be finished as below, except for the “raked” and “struck” options. brick joints

  • I've added an extra photo above to original post to show the entire back of that wall viewed from the ground. The top is capped with stone which is wider than the brickwork. Further down from that point we don't see the same issues and we don't see this over the remainder of the house, despite being the mortar not being flush with the brickwork
    – Fraser
    Jul 9, 2018 at 9:39
  • Is that cap made of stone? What kind? What exactly is it made of? Are there seams or cracks in it? The width of that cap is pretty stingy... Would love to see it extend out several more inches. That wall is almost definitely getting too wet. There will be no easy repair... it would help to fill any cracks in the cap with a butyl rubber sealant, or cast lead if you wanna go old school.
    – paul
    Jul 9, 2018 at 10:47

I'm not a mason so I can only answer your first question:

1) What is causing this?

Winter. You've got some ornate texture on those bricks - so brick gets wet, brick gets cold, water in crevasses freezes, expands, breaks the texture off, causes micro-cracks in the remaining brick, which then gets water in it, and the cycle continues.

  • 1
    The type of brick used may not be the correct type for that application. I would check with local brick masons
    – d.george
    Jul 5, 2018 at 18:41

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