Many home owners are nervous when they see cracks in concrete and wonder if they are bad or dangerous.
After the recent 7.3 magnitude quake which struck off the Cariaco peninsula and rocked our twin island nation Trinidad and Tobago, a lot of Trinbagonians have spotted cracks in the structural concrete walls, floors and beams of their homes. Being shaken up by such a strong force of nature, any home owner would be concerned about the structural integrity of their homes. This blog aims to explain the different types of crack that can form in a home. However, if you are seeking a solution to your home’s cracks, we do recommend you consult with a registered structural engineer for expert advice on the topic.
Quite a few people have spotted cracks in their homes concrete almost immediately after the earthquake and were concerned about their homes safety. The good and bad news is that not all cracks are the same, and there is a big difference with the impact that a structural crack can have on your home vs. a non-structural one.
Structural Vs. Non-Structural Cracks
Non-Structural Cracks can occur anywhere in a home’s foundation to its walls and beams. They usually originate from openings in the wall, like windows or doors. These cracks are usually very thin, and referred to as hair line cracks and have no impact on the structural integrity of your home.
Structural Cracks in concrete walls and floors normally occur in patterns. These cracks may run up at an angle from the lower corners of the wall. Other patterns that these cracks show up in is a vertical crack in the center or even angled cracks from each corner of the wall and intersected by a horizontal crack in the center of the wall.
The Type of Crack Matters!
The thickness of the cracks in these patterns are a very important signal as to how severe the damage is.
• Cracks less than .1 mm are referred to as hairline cracks and are completely negligible. No repairs are needed for hairline cracks.
• Fine cracks are cracks with a thickness up to 1 mm and usually only damage the wall finishes. These cracks can be treated with a simple paint job.
• Recurrent cracks can have a width of 1 mm to 5 mm and can be fixed simply by using a suitable lining to fill the cracked space, followed up with an external paint job. These cracks are an easy fix, and are not too damaging to your homes structural integrity.
• Cracks that require some opening up, and patching up by a mason are cracks between 5 mm to 15 mm, or even several 3 mm cracks in one area. In some cases, a small amount of bricks may even have to be replaced.
• Cracks between 15 mm to 25 mm are extremely damaging to the structural integrity of your home’s concrete. These cracks are usually fixed by breaking down and replacing sections of structural concrete members in your home. These cracks greatly inhibit the bearing capacity of beams, and loading capacity of structural walls and should be reviewed by a reputable structural engineering team.
• Finally, cracks that cause severe structural damage are crack widths greater than 25 mm. These cracks cause extreme structural instability. Cracks like these can usually only be fixed by completely removing old walls or floors and reconstructing new concrete.
There are a number of alternative methods that can be used to fix structural cracks:
1. Injecting the crack with urethane to permanently seal it.
2. Install carbon fiber strips to damaged walls.
3. Using resistance and helical piers to level sinking and settling foundations