Container House Bottom Rot

Container house bottom rot is usually caused by water accumulation and rust at the bottom, poor-quality floor materials, or structural damage, and can be prevented through strict inspection and regular maintenance.

Water Accumulation and Rust at the Bottom Are the Main Causes

If water accumulates at the bottom of a container house for a long time, it will accelerate the rusting of steel, causing the bottom crossbeams to bend or even rust through. For example, the inspection standards for second-hand container houses clearly require that there be no water accumulation or rust at the bottom; otherwise, the purchase should be abandoned directly. Water accumulation not only corrodes the steel but also damages the insulation layer, causing the rock wool to become damp, clump, turn black, lose its insulation effect, and be prone to mold growth. In northern regions, due to the cold winters, if the insulation fails, the living value of the house will be greatly reduced.

Floor Material and Installation Quality Affect Durability

Poor-quality floors (such as those that are soft or have mildew spots and holes) will directly lead to "bottom rot". When inspecting second-hand container houses, a tread test is required. If the floor is soft or has holes, the replacement cost is extremely high. High-quality container houses should use floor materials that are corrosion-resistant and have strong load-bearing capacity, and ensure tight connection with the bottom structure during installation to avoid water accumulation in gaps. In addition, a drainage slope should be set under the floor to prevent rainwater from flowing back.

Structural Damage and Welding Process Defects

Cracks in the welds or bending and rusting through of the four corner columns and bottom crossbeams will seriously weaken the stability of the house. For example, a container house in Haiyan, Jiaxing collapsed in an 8-level gale due to structural problems such as the tilting and deformation of the metal frame and shallow nail fixation. When purchasing, priority should be given to choosing a thickened galvanized square tube frame and confirming that the welding process is a full-weld structure to enhance the overall wind resistance. At the same time, avoid open-flame operations around the house to prevent high temperatures from deforming the steel.

Preventive Measures and Maintenance Recommendations

1. Regular Inspection: Check the bottom drainage system, floor condition, and weld integrity every six months, and promptly clean up accumulated water and apply anti-rust paint.
2. Waterproof Treatment: The roof should adopt a multi-layer waterproof structure, and the joints of the panels and the positions of the screws should be sealed and reinforced to prevent rainwater from seeping into the bottom.
3. Environment Selection: Avoid placing container houses in low-lying areas prone to water accumulation. If necessary, raise the foundation or set up drainage ditches.