Ceiling collapse is the technical definition of what happens when the ceiling collapses. Ceiling collapse, however, is too general a term because it does not explain exactly what happened. The plaster or even just the paint on a ceiling or ceiling panel may fall off.
On the other hand, collapse is more serious damage because it involves the detachment of the brick base in buildings constructed of reinforced concrete.
In these structures, the slab consists of hollow bricks, blocks of brick that fill the space between the steel joists that make up the brick structure. If, for any reason, the steel mesh no longer fills the spaces between the joists and suffers corrosion effects, swelling will occur, causing the bottom to fail.
Floor slab caving: causes and interventions
This damage does not compromise the structural integrity, but it poses a serious risk to the safety of anyone present in those spaces if they are unlucky enough to be there when the plaster falls.
Before reaching that point, however, the ceiling will almost certainly have already shown signs of deterioration, such as bulging and sagging plaster. This is why it is important to intervene at the first signs to avoid having to later resort to more invasive interventions to repair greater damage.
You don’t need to be an expert to notice cracks and bulges in a ceiling.
One of the main causes of this phenomenon is called carbonation, a chemical process that corrodes the steel core of concrete. This phenomenon, accompanied by the presence of chloride ions, can deeply degrade a brick structure to the point of causing it to detach. This can also happen in buildings that are not too old, if they have not been built to a high standard.
When signs of this type become visible, it is necessary to take action as soon as possible to prevent collapse, which would require more extensive restoration work. In the event of collapse, it is first necessary to replace the steel structure and then fill the empty spaces with insulating material.
To prevent the same problem from occurring in the future, Shove mortar can be used, a special material now available on the market for this purpose.
The consequences of floor slab debonding
Breaking through the floors will probably not cause the building structure to collapse, however, it is a major safety issue, directly affecting the safety of people residing in or attending such facilities. It has to be said that although crumbling is an indicator of deterioration, this does not necessarily compromise the load-bearing capacity of the building, but it does highlight an advanced stage of deterioration, particularly related to concrete carbonation. This chemical process, as mentioned above, results in corrosion of the metal reinforcement, increasing the risk of slab debonding.
However, this problem does not only affect old buildings or those in an obvious state of disrepair; even newly constructed structures can be subject to crumbling, making this risk a common concern for all types of buildings. Brick floors are used in both historic and modern buildings, and the age of the building is not a primary factor when it comes to vulnerability to concrete carbonation.
Teknoprogetti has been carrying out detailed analyses of the security status of buildings for many years, and is able to perform a thorough diagnostic report to plan the necessary interventions to ensure a higher level of security.
Recognize indicators of subsidence in floors
The slab failure is the result of the neglect of many signs that preceded it. Over a shorter or longer period of time, the attic usually shows moisture stains or presence of mold indicating the presence of water infiltration. Water is certainly one of the elements that most harm the tightness of concrete rebar.
A second phenomenon that can occur that shows signs of slab degradation is the presence of cracks or fissures that alter the ordinary appearance of the surface. Their depth will indicate whether they are superficial damage that can be repaired by replastering, or deeper cracks that require further investigation.
The same applies to the appearance of bubbles, bulges, or depressions in the plaster: it is necessary to assess their extent and whether they show signs of moisture, which would indicate the presence of leaks. All of these occurrences, although small, can cause small detachments of material that could, however, be the precursor to more extensive subsidence.
Breaking through rarely occurs without any of the preceding events having occurred, but if episodes of concrete carbonation have become evident in the same building, it is worth doing more in-depth analysis to avert the hypothesis of corrosion of the structure without its effects showing yet.
How to repair a collapsed slab
Repairing the slab breakthrough involves the new installation of a load-bearing structure. It involves recreating a substrate on which to rest the slab, after filling the voids with insulation material. Of course, first the damaged parts are cleaned and the deteriorated material is removed. At this point, the damaged steel reinforcement is replaced to restore the load-bearing joists to full working order.
It is important to fill the spaces left empty by the breakthrough with polystyrene or expanded polystyrene, which not only restores the uniform surface of the attic but also provides excellent acoustic and thermal insulation.
In order to prevent the concrete reinforcement from corroding again, resulting in the breakthrough, it is recommended to install an anti-breakthrough mesh made of fiberglass. The existence of this material proves that these are widespread phenomena in construction, for which research continually offers new solutions and guarantees against the risk of future subsidence.
Where possible, you can consider installing a plasterboard false ceiling to cover the imperfections caused by the collapse. With this method, the attic is effectively repaired and preventive measures are put in place to help improve the safety of the building.
