Arch and Lintel Failure: Causes, Solutions, and Prevention

Arches and lintels are common architectural features that can be found throughout many heritage buildings in Sydney. They are typically used to support the weight of a structure and span across doorways, windows, or other openings.

An arch is a curved structure that spans from one side of an opening to another. You can commonly find them made from stones or bricks. On the other hand, a lintel is a horizontal beam above a doorway or window opening typically made of concrete.

What Is Arch Bar and Lintel Failure?

Failure on the lintel or arch bar in a masonry structure tends to occur when the mortar between bricks cracks or breaks down over time. The first sign of an arch bar or a lintel failure is the presence of vertical cracks above the windows or on the arch.

This can lead to structural problems like crumbling or cracking of the mortar joints—which may cause water damage inside your home or business. In some cases, it can also lead to the failure of the entire structure of your wall.

These structural failures are especially common in older buildings that were constructed before modern building standards that are apparent today. Older buildings tend to have thinner mortar joints than newer buildings, which makes them more delicate to deterioration, hence a major factor in the failure of lintels and arches over time.

Some of the factors that cause arch bar and lintel failure include:

Inadequate Mortar Joint Width

Inadequate mortar joint widths can reduce the load-bearing capacity of an arch and increase the likelihood of failure. This is often caused by improper installation, or by insufficient bonding due to a thin mortar joint or lack of grout coverage.

Ground Subsidence

Ground subsidence can cause an arch to crack and eventually collapse completely. This is often caused by ground movement due to earthquakes or other natural disasters, but it can also be caused by excessive loads on an arch bar (which causes it to sink into soft ground).

Improper Installation

Improper installation is another common cause of failure among arches and lintels. This occurs when your contractor does not pay attention to detail and cuts corners in doing your lintels and arches just for the sake of finishing their jobs quickly.

Mortar Fretting

Mortar fretting occurs when the mortar between the bricks or stones in an arch starts to deteriorate and break down, causing the arch itself to lose its structural integrity.

Excessive Loading on the Lintel or Arch Bar

When the weight of the lintel or arch bar is excessive, it can overload the structure of the arch and cause it to fail. This happens when the load-bearing capacity of an arch is exceeded by too much weight being placed on it.

Lintel and Arch Failure Solutions and Preventions

To prevent lintel and arch failure, it's important to know what the common causes are and how you can prevent them from occurring.

If you have a lintel or arch failure, there are several things you can do to fix and prevent them from happening. Here are some of them:

1. Check for signs of damage 

Look at the floor under the lintel or arch and see if there are any cracks, bulges, or other visual signs of damage. If so, contact a professional for assistance immediately.

2. Contact a professional for assistance

If there is no visible sign of damage but you still suspect that there might be something wrong with your lintel or arch, get in touch with an engineer to come out and inspect it for you.

3. Replace the lintel or arch if necessary

If your lintel or arch needs replacing, go ahead and do so right away! The longer you wait to fix a problem like this, the more likely it will be that further damage will occur—and the more expensive it will be to replace down the line!

4. Plan ahead

If you're planning on building a new home or structure in an area prone to earthquakes or high winds, make sure that you consider adding extra support pillars around doors or windows so they don't blow off their hinges during these conditions as well!

5. Have a regular maintenance

Another way to prevent lintel and arch failure is through regular maintenance. If your building has a brick facade or other exterior surface made out of brick or stone, this needs to be maintained regularly to prevent damage over time.