What causes brick walls to crack?
Brick walls crack when natural elements or man-made environmental impacts compromise the masonry materials causing them to shift, buckle and crack under the weight of the forces applied.
SB Tuckpointing masonry experts can visit your house and inspect the cracked brick wall and surrounding areas to determine what the cause of your degrading brick wall may be. In the meantime, here are some reasons your external brick walls may be cracking:
Your brick walls should be built on some steady foundations to ensure the least amount of movement holding up your heavy house. If a significant amount of soil gets disrupted, uncompacted or moved away from the base it could cause the bottom of the rigid brick wall to shift and create cracks throughout.
Removing large trees in the area may also cause local destabilisation to the soil making it decompress to fill the void previously filled with firm tree roots. The looser soil and decompression may cause brick walls to crack because the foundations have dipped.
Climate and season change
Your brick walls are constantly exposed to the temperamental Melbourne and Hobart weather elements and a wide variation of temperatures from freezing cold during winter mornings to baking hot in peak summer sun.
Your brick and mortar are highly durable and highly water resistant but can degrade over the years and decades (like anything). When the mortar crumbles away and the bricks are looser and more exposed the wall integrity degrades and may start to flex - but being a rigid brick wall, it starts to crack.
One of the most common causes of cracked bricks is foundation issues. If your house isn’t built upon steady ground that has become uneven over time then the brick wall is going to try and flex, but being made of rigid brick and mortar, the bricks will crack and the mortar will degrade and fall away.
Usually there are other signs of significant foundation problems that can accompany cracked bricks, such as doors that don’t shut properly, floor cracks, wall fissures, interior wall cracks and broken chimneys, so keep an eye on the signs.
It’s an unfortunate fact of life that there are dodgy contractors out there trying to finish builds fast and cheap which usually causes brick houses to degrade and require repairs sooner rather than later.
Melbourne has some comprehensive construction regulations to follow however when combined with age, wild weather and questionable craftsmanship your brick wall may need maintenance or experience damage sooner than expected.
Degrading construction materials
Even if the construction of the brick wall and surrounding foundations was of a quality build, cracks can appear in a brick wall through the degradation of construction materials used - especially if the brick house is decades old.
Brick and mortar generally ages well but with historic and heritage houses it’s difficult to tell what construction material they had access to at the time and the brick and mortar maintenance measures taken through the years.
Brick and mortar are highly water resistant and can last decades when properly constructed, but they aren’t meant to have prolonged periods of time being wet or submerged in water. Leaking pipes, improper drainage and years of rain can penetrate the brick wall . If you live in an area that experiences freezing temperatures the masonry can be compromised with moisture then through the process or freezing and thawing the mortar can push out the bricks causing them to crack.
Rising Damp is another potential cause of cracked bricks which is the process of water and moisture containing salts from the ground to rise up the brick walls making mortar crumble and bricks to degrade. Tuckpointing or Repointing is a recommended technique for preventing water damage in bricks.
Trees in close proximity
Tree roots are unseen and slow to grow but can have some serious ground-moving strength. You may have seen cracks and raised pavement near trees - it is much the same for brick walls and mortar but instead of having space to be pushed up, the weight of the house will cause the brick wall to flex outwards and quickly fracture and crack.
A great way to keep the leafy foliage to compliment your brick wall, without the hazard of cracking bricks and mortar, is to only plant shrubs, bushes and flowers which typically don’t have an invasive root system.
SB Tuckpointing always recommends fixing cracked brick walls early to avoid worse problems in the future.