Cracking of Floor Tiles in Old Houses with Prefabricated Slabs

For cracking of floor tiles in old houses with prefabricated slabs, targeted treatment should be carried out according to the crack conditions, and attention should also be paid to potential structural safety hazards. The specific steps and precautions are as follows:

I. Crack Treatment Steps

1. Surface Treatment
   Thoroughly remove dust, oil stains, and loose impurities from the cracks to ensure that the interior of the cracks is dry and clean. At the same time, clean up the loose adhesives between the tile joints to avoid affecting the bonding effect of subsequent joint-filling materials. This step is the foundation for ensuring the quality of the repair. If pollutants remain, it will lead to poor bonding between the joint filler and the base layer, which may easily cause secondary cracking.

2. Joint Filler Preparation
   Add clean water to the tile joint filler in a powder-to-water ratio of 4:1. Use a low-speed electric drill (equipped with a suitable mixing blade) to mechanically stir it into a uniform paste. During the stirring process, control the time to avoid excessive stirring that may degrade the material properties. After preparation, use it as soon as possible to prevent the joint filler from curing and affecting the construction effect.

3. Joint Filling and Finishing
   Before joint filling, wipe the surface of the floor tiles with a damp cloth (without leaving standing water). Fill the prepared joint filler evenly into the cracks and smooth the surface with a scraper or trowel. After joint filling, check it in a timely manner and repair any flaws such as bulges or depressions to ensure that the surface flatness meets the requirements. In this step, pay attention to the compactness of the joint filler filling to avoid voids that may lead to repair failure.

4. Subsequent Curing
   Before the joint filler cures (usually 24-48 hours), avoid stepping on it or placing heavy objects on it, and keep the joint-filling area dry. If the environmental humidity is high, the curing time can be appropriately extended. During the curing period, if cracks appear on the surface of the joint filler, it should be refilled in a timely manner.

II. Structural Safety Precautions

1. Risk Assessment
   Cracking of the floor in old houses with prefabricated slabs may reduce the structural load-bearing capacity, accelerate the aging of the house, and even lead to the risk of collapse. If the cracks are accompanied by phenomena such as increased deflection of the prefabricated slabs and cracking of the walls, a professional institution should be immediately commissioned to conduct a structural safety assessment.

2. Tile-Breaking Operation Specifications
   If the operation is proper during the first tile-breaking, the floor tiles under the prefabricated slabs usually will not crack. However, with each additional tile-breaking operation, the crack resistance of the prefabricated slabs will significantly weaken. During the operation, control the angle of the impact drill to avoid vertically impacting the ground. Instead, insert the drill bit obliquely between the decoration layer and the structural layer to reduce the direct impact force on the prefabricated slabs.

3. Neighbor Protection Measures
   When carrying out vibration operations such as tile-breaking in old houses, communicate with the downstairs residents in advance and take measures such as laying buffer pads and controlling the operation time to avoid the ceiling falling off or pipeline damage in the downstairs area due to vibration. If the house is very old, it is recommended to give priority to non-destructive testing methods to assess the structural condition.