How to Build a Prefabricated House Mezzanine

The construction of a prefabricated house mezzanine should follow standardized procedures, with core steps including construction preparation, measurement and layout, steel bar planting, prefabricated panel hoisting and fixation, and joint treatment, while also paying attention to load-bearing design and curing requirements.

I. Construction Preparation

1. Material Preparation:
   • Prefabricated mezzanine panels: Made of reinforced concrete prefabricated components, with specifications of length 2400-3600mm, width 600mm, and thickness 120mm. The concrete strength grade is C30, with main reinforcement of HRB400E grade φ12mm steel bars, distribution reinforcement of φ8mm @ 200mm, and reserved tongue-and-groove joints and hoisting rings at the panel ends.
   • Connection materials: E43 type welding rods, 40×60×4mm connecting steel plates, φ10mm connecting steel bars (with hooks at both ends), steel bar planting adhesive with a tensile strength ≥ 30MPa, and φ12mm threaded steel bars for steel bar planting with a depth ≥ 120mm.
   • Auxiliary materials: P.O 42.5 grade cement, C35 fine aggregate concrete, polyurethane sealant, wooden beams, and steel pipes, etc..
2. Equipment and Site:
   • Equipment: 25t truck crane, electric welding machine, steel bar planting drill, level gauge, etc..
   • Site: The storage area for prefabricated panels should be leveled and compacted, with vertical stacking height ≤ 6 layers and wooden beams placed between layers. After the main structure is accepted, clean the installation area and set out control lines (with an error of ≤ 3mm for axis and elevation lines).

II. Key Construction Techniques

1. Measurement and Layout:
   • Axis control: Snap the installation axis on the wall, with a deviation ≤ 2mm, and the panel end positioning line is 100mm away from the panel end.
   • Elevation control: Set out a +1.000m elevation line on the wall column, deduce the panel top elevation, with an allowable deviation of ±3mm.
2. Steel Bar Planting:
   • Drilling: Hole diameter φ14mm, depth 120mm, with a perpendicularity deviation ≤ 3° and a hole spacing deviation ≤ 10mm.
   • Hole cleaning: Blow the hole with a high-pressure air pump 3 times, clean the hole wall with a wire brush, and wipe with acetone.
   • Glue injection and steel bar planting: Inject glue into the hole to a depth of 2/3, insert the steel bar and rotate.
3. Prefabricated Panel Hoisting and Fixation:
   • Hoisting: Use a truck crane to hoist to the installation position, with temporary supports made of wooden beams or steel pipes.
   • Fixation: After adjusting the panel position, fix it by welding with connecting steel plates and φ10mm steel bars, and fill the panel joints with C35 fine aggregate concrete.
4. Joint Treatment:
   • Panel joint waterproofing: Fill with polyurethane sealant, with an elongation ≥ 300%.
   • Formwork removal: Remove the formwork after the concrete reaches the design strength.

III. Precautions

• Load-bearing design: The mezzanine span should be adjusted according to the actual load-bearing capacity of the house, and if necessary, calculated by a professional engineer.
• Concrete mix ratio: Strictly mix according to the ratio of cement:river sand:gravel = 1:2:3, and vibrate with a special vibrator.
• Curing requirements: The floor slab should be fully cured to ensure stability and durability.