How to Build a Balcony for Prefabricated Panel Houses

Building a balcony for a prefabricated panel house requires strict adherence to construction procedures and key points to ensure structural safety and functional integrity. The specific steps are as follows:

I. Pre-construction Preparation and Inspection

1. Inspection and Reinforcement of the Original Structure:

   • Inspect the position and spacing of steel bars in the ring beams of the main structure (main bar spacing ≥ 200mm) and the overhanging length of the balcony (resting length ≥ 100mm) to ensure compliance with design specifications.
   • If the original structure has issues such as rusted steel bars or cracked panel joints, reinforcement is required. For example, chemical anchors can be implanted into the ring beams and welded with the reserved steel bars of the prefabricated panels to enhance connection strength.
   • For renovation of old houses, the original prefabricated panels need to be removed and rebuilt using a combined structure of "prefabricated panels + cast-in-place layer" to improve durability and waterproofing.

2. Customization and Inspection of Prefabricated Panels:

   • Customize prefabricated panels based on measured data to ensure that panel thickness (120mm, with an allowable deviation of ±5mm), reserved steel bar positions, and protective layer thickness meet design requirements.
   • During inspection, provide factory certificates and concrete test block compression reports (design strength C30, with a 28-day measured strength ≥ 31.5MPa) to ensure material quality meets standards.

II. Construction Process

1. Base Cleaning and Marking:

   • Remove debris and loose concrete from the original structural surface in the balcony area to ensure a solid base.
   • Mark the position lines and elevation control lines for the balcony panel and air conditioning panel according to design requirements to provide a reference for subsequent construction.

2. Support Installation and Elevation Adjustment:

   • Install the support system for the balcony panel and air conditioning panel and securely tie it to the inner side of the structure to prevent support displacement.
   • Adjust the elevation of the panel bottom supports to ensure compliance with design requirements and avoid height differences after the installation of the prefabricated panels.

3. Prefabricated Panel Hoisting and Verification:

   • Hoist the prefabricated panels to the installation position and verify their elevation and position to ensure installation accuracy (with errors controlled within specified limits).
   • Temporarily tie the prefabricated panels to prevent displacement due to external forces during construction.

4. Steel Bar Binding and Concrete Pouring:

   • Bind the steel bars of the prefabricated panels firmly with the beam and slab steel bars to form an integrated load-bearing system and enhance structural stability.
   • Pour concrete for the beam and slab (mix ratio: cement:sand:stone:water = 1:1.8:2.7:0.45, with 8% waterproofing agent added) and control the slump at 180±20mm to ensure concrete fluidity and strength.
   • Clean the base before pouring to prevent poor adhesion between new and old concrete, which could lead to cracks.

5. Support Removal and Curing:

   • Remove the support system after the concrete reaches the specified strength (usually above 75% of the design strength).
   • Cure the concrete to prevent cracking due to rapid water loss.

III. Handling Special Cases

• If the overhanging beam is a prefabricated component, pre-arrange steel bars and connect them with the steel bar mesh during on-site pouring of the panel to form a unified whole.
• During construction, adjust the overhanging length of the beam and the installation position of the prefabricated panel to ensure a flat joint and achieve a firm connection by binding steel bars or welding reserved steel bars.