Cracks In Your Building - When Should You Be Worried?
Cracks appearing in any building tend to cause certain amount of anxiety and distress among property owners. On top of the pain in seeing your beautiful renovation and imported finishes disintegrate into thousands of tiny pieces, there is the greater worry of whether the building is safe for occupancy. I am not able to come up with an all encompassing guideline on structural vs non-structural cracks or superficial vs dangerous cracks. Even a structural engineer would have to review each case individually and assess the structural design of the building before coming to any form of conclusions on the possibilities and reasons for cracks in buildings. Similar to doctors, an engineer would need to spend time to look at the symptoms of the cracks in the building, study the history of the building changes, understand its foundations (see my earlier post on FOUNDATIONS) and much more before they can propose a diagnosis and recommend a solution.
However, what I can try to achieve in this post would be to generate awareness on some common cracking problems and also provide property owners with some basic understanding of cracks within a building structure, so that they can take the correct initial steps to rectifying the problem or to call in professional support and possibly urgently in some cases.
Cracks are formed due to excessive building movement. As the finishes and materials used for constructing buildings are generally very stiff and brittle, they do not have the ability to STRETCH or ELONGATE to accomodate large building movements.
For example if you try to bend a piece of floor tile or marble slate, it will crack and snap into two. As opposed to a steel bar, which can bend and remain bended. We call that 'ductility' in engineering terms. If you think about the majority of the materials used in the typical Malaysian building (concrete, bricks, cement plaster and tiles) it is not surprising that cracks are commonly seen in our buildings.
It is important for building owners to understand that it is IMPOSSIBLE to have a crack free building. Everything cracks and it is a question of how much and whether it is visible to the naked eye. Even the concrete beam above your head, as you sit at your table in the office or at home reading this, has cracks that are microscopic that will not be visible to the naked eye. These cracks are expected and taken into account in the structural design by the engineer.
However, when cracks become clearly visible to the naked eye, it indicates a problem. It may be crucial, it may not be. But clearly a problem. In some buildings you may feel that 'you don't see any cracks' and that usually means the interior designer has done a good job in shadowing such eye sores. The trick would be to know where it is, hide it and not fight it. But that is a different topic all together and beyond the scope of this post.
New Property
I would usually expect new properties to have more cracks than older buildings. Notice that I used the word 'usually' and solely because there are circumstances which can cause old buildings to develop cracks as well.
In general, newly built properties are sitting on new foundations and the finishes are new. As such, there are more building movement expected. Some typical forms of building movement are settlement of the foundations and drying shrinkage of the construction materials.
Drying shrinkage cracks are very common. If you look at a typical property in Malaysia during the construction phase, you will realise that majority of the building materials involve the use of 'water'. The main building material being concrete requires water to mix before it is poured and hardened. Cement-sand filling or plaster used to build and render the floors and walls require water as well. Therefore, a lot of the water remain trapped within the finishes even after the works are complete and slowly escapes over time, causing shrinkage in many of the floor and wall finishes. As such, it is common to find such cracks appearing in newly completed units at the time that you collect your keys. In fact, it is expected for such cracks to continue manifesting itself for some months after a building is newly completed.
Cracks of such nature are usually very fine (hairline) and random in nature. They are generally not dangerous, unless wall tiles are loosened as a result and falls off.
Such cracks would be even more profound if the finishes were applied in a hurry after the completion of the wet works such as concreting, floor screeding and plastering before there is sufficient time for the majority of the moisture to escape. Therefore, it is not advisable to rush the completion of the various stages of finishes. However, from my experience, floor and wall finishes are usually scheduled towards the end of construction projects and renovation projects. As such, contractors are usually pressured to complete the project according to the deadlines and end up rushing through these stages. My advise would be for you to provide ample time for these finishes to reduce shrinkage induced problems from appearing later.
When cracks or loosening of finishes occur after your renovations are complete, it is VERY DIFFICULT to repair and achieve a clean finish to match the existing finishes. For example, the paint or tiles on your wall is already exposed to dirt and oxidisation since the completion of the building. Even if you use the same tile or paint to repair the affected area, the repaired area will clearly stand out from the surroundings due to the new condition of the paint or tile used.
Attached below are some photos of typical shrinkage cracks.
In the first 2 photos, cracks appear at the junction between the brickwall and the concrete columns and beams. This is usually caused by poor jointing between the bricks and concrete elements with improper filling of the gaps at the interface, causing a line of weakness for the shrinkage effects to concentrate on. The third photo shows an example of poor joint filling between brickwall and concrete column, giving rise to such cracks on the cement plaster after completion. These cracks are generally not dangerous, but may pose a problem for water penetration if one side of the wall is exposed to external weather.
In the last photo, the cracks have been hacked for repairing and taking the photo. So they appear to be wider than usual. The main point to note is the irregular and random pattern. Again these cracks are usually not dangerous and the cracks generally do not extend below the cement plaster layer. In other words, if you chip of the cement plaster layer along the crack line, cracks SHOULD NOT be seen on the bricks forming the wall itself.
Why Are There Cracks In The First Place?
For example if you try to bend a piece of floor tile or marble slate, it will crack and snap into two. As opposed to a steel bar, which can bend and remain bended. We call that 'ductility' in engineering terms. If you think about the majority of the materials used in the typical Malaysian building (concrete, bricks, cement plaster and tiles) it is not surprising that cracks are commonly seen in our buildings.
It is important for building owners to understand that it is IMPOSSIBLE to have a crack free building. Everything cracks and it is a question of how much and whether it is visible to the naked eye. Even the concrete beam above your head, as you sit at your table in the office or at home reading this, has cracks that are microscopic that will not be visible to the naked eye. These cracks are expected and taken into account in the structural design by the engineer.
However, when cracks become clearly visible to the naked eye, it indicates a problem. It may be crucial, it may not be. But clearly a problem. In some buildings you may feel that 'you don't see any cracks' and that usually means the interior designer has done a good job in shadowing such eye sores. The trick would be to know where it is, hide it and not fight it. But that is a different topic all together and beyond the scope of this post.
Age of the Building
New Property
I would usually expect new properties to have more cracks than older buildings. Notice that I used the word 'usually' and solely because there are circumstances which can cause old buildings to develop cracks as well.
In general, newly built properties are sitting on new foundations and the finishes are new. As such, there are more building movement expected. Some typical forms of building movement are settlement of the foundations and drying shrinkage of the construction materials.
Drying shrinkage cracks are very common. If you look at a typical property in Malaysia during the construction phase, you will realise that majority of the building materials involve the use of 'water'. The main building material being concrete requires water to mix before it is poured and hardened. Cement-sand filling or plaster used to build and render the floors and walls require water as well. Therefore, a lot of the water remain trapped within the finishes even after the works are complete and slowly escapes over time, causing shrinkage in many of the floor and wall finishes. As such, it is common to find such cracks appearing in newly completed units at the time that you collect your keys. In fact, it is expected for such cracks to continue manifesting itself for some months after a building is newly completed.
Cracks of such nature are usually very fine (hairline) and random in nature. They are generally not dangerous, unless wall tiles are loosened as a result and falls off.
Such cracks would be even more profound if the finishes were applied in a hurry after the completion of the wet works such as concreting, floor screeding and plastering before there is sufficient time for the majority of the moisture to escape. Therefore, it is not advisable to rush the completion of the various stages of finishes. However, from my experience, floor and wall finishes are usually scheduled towards the end of construction projects and renovation projects. As such, contractors are usually pressured to complete the project according to the deadlines and end up rushing through these stages. My advise would be for you to provide ample time for these finishes to reduce shrinkage induced problems from appearing later.
When cracks or loosening of finishes occur after your renovations are complete, it is VERY DIFFICULT to repair and achieve a clean finish to match the existing finishes. For example, the paint or tiles on your wall is already exposed to dirt and oxidisation since the completion of the building. Even if you use the same tile or paint to repair the affected area, the repaired area will clearly stand out from the surroundings due to the new condition of the paint or tile used.
Attached below are some photos of typical shrinkage cracks.
In the first 2 photos, cracks appear at the junction between the brickwall and the concrete columns and beams. This is usually caused by poor jointing between the bricks and concrete elements with improper filling of the gaps at the interface, causing a line of weakness for the shrinkage effects to concentrate on. The third photo shows an example of poor joint filling between brickwall and concrete column, giving rise to such cracks on the cement plaster after completion. These cracks are generally not dangerous, but may pose a problem for water penetration if one side of the wall is exposed to external weather.
In the last photo, the cracks have been hacked for repairing and taking the photo. So they appear to be wider than usual. The main point to note is the irregular and random pattern. Again these cracks are usually not dangerous and the cracks generally do not extend below the cement plaster layer. In other words, if you chip of the cement plaster layer along the crack line, cracks SHOULD NOT be seen on the bricks forming the wall itself.
Foundation Movement and Excessive Structural Deflections
You can read my previous post on foundations to understand how the foundation movement affects your property, causing it to crack at various locations in some instances. In summary, most cracks that are formed due to excessive relative movement of foundations will occur close to the columns and support points of the building. The cracks will appear to follow a systematic pattern as opposed to random shrinkage type cracks mentioned above.
Similarly, if structural elements such as beams and columns have been under-designed, these elements will move beyond the allowable limits under load (we usually call these movement 'deflections') causing cracks to brick walls and associated floor and wall finishes.
These cracks usually have corresponding patterns, tends to include diagonal crack directions and tend to be much longer than shrinkage cracks.
Furthermore, if you remove the cement plaster layer along the cracks and the cracks penetrate through to the brick wall or concrete elements, it is time to get someone to look at the problem as soon as possible. Having cracks through the entire thickness of a wall is an indication of relatively significant movement of the structure beyond the designed limits
Below are some photos showing some examples of more serious cracks caused by foundation movements and excessive structural deflections. Again, the cracks have been hacked wider for repair and they seem wider than the original. Therefore, do not look at the width of the cracks but focus on the crack patterns. Take note of the regular diagonal patterns and in some photos you can see similar diagonal crack directions on the wall in front and the wall behind.
You can read my previous post on foundations to understand how the foundation movement affects your property, causing it to crack at various locations in some instances. In summary, most cracks that are formed due to excessive relative movement of foundations will occur close to the columns and support points of the building. The cracks will appear to follow a systematic pattern as opposed to random shrinkage type cracks mentioned above.
Similarly, if structural elements such as beams and columns have been under-designed, these elements will move beyond the allowable limits under load (we usually call these movement 'deflections') causing cracks to brick walls and associated floor and wall finishes.
These cracks usually have corresponding patterns, tends to include diagonal crack directions and tend to be much longer than shrinkage cracks.
Furthermore, if you remove the cement plaster layer along the cracks and the cracks penetrate through to the brick wall or concrete elements, it is time to get someone to look at the problem as soon as possible. Having cracks through the entire thickness of a wall is an indication of relatively significant movement of the structure beyond the designed limits
Below are some photos showing some examples of more serious cracks caused by foundation movements and excessive structural deflections. Again, the cracks have been hacked wider for repair and they seem wider than the original. Therefore, do not look at the width of the cracks but focus on the crack patterns. Take note of the regular diagonal patterns and in some photos you can see similar diagonal crack directions on the wall in front and the wall behind.
.jpg)
Finally, I am attaching a few closeup photos showing cracks that have penetrated through the brickwalls indicating significant structural movement causing such cracks.
Conclusion
In parting conclusion for this post on cracks, I reiterate that I am not able to cover all cracking circumstance in one blog post such as this. However, with the aid of some of the visual aids posted above, I hope that I have been able to give you a better idea on some of the common cracking phenomenons that manifest in a typical concrete structure residential building with built up brick walls. If you do notice some of the more severe cracking patterns similar to those seen above and continue to elongate and penetrate through the brickwork, do make sure you get someone to look into it as soon as possible.
