How to Prefabricate the Large Eaves of a House

The prefabrication of large eaves for houses can employ the technology of constructing eaves using concrete prefabricated panels. The specific steps and techniques are as follows:

I. Steps for Prefabricated Panel Eaves Projection

1. Determine the height and length of the eaves projection: This should be determined based on the overall building design, drainage requirements, and regulatory standards. The drainage slope should be ≥2%, and the projection length is typically 500-800mm to ensure effective rainwater drainage and avoid structural instability due to excessive length.
2. Install the eaves projection support structure: Select the support form (such as steel beams or concrete cantilever beams) according to the design, ensuring that its load-bearing capacity meets the requirements of the prefabricated panels and construction loads. The support structure must be reliably connected to the main structure, for example, using M12 expansion bolts or epoxy resin anchors for fixation.
3. Install the prefabricated panels: Use equipment such as truck cranes to lift the prefabricated panels onto the support structure and adjust their positions to align with the design axes. The prefabricated panels should be made of C30 concrete with built-in φ8@150 bidirectional steel reinforcement mesh to ensure structural strength.
4. Connection and sealing: Connect the prefabricated panels using welding or bolts, and fill the joints with C40 non-shrink grout for a dense seal. Lay a 3mm thick SBS modified bitumen waterproof membrane at the junction between the panels and the main structure, and seal the gaps with polyurethane sealant to prevent leakage.
5. Coating treatment: After surface cleaning, apply waterproof coating or decorative paint to enhance durability and aesthetics.

II. Key Construction Techniques

1. Specification selection: The size of the prefabricated panels should match the projection length, with a single panel length not exceeding 3m to reduce transportation risks. The thickness should be determined based on load calculations, typically ranging from 80-120mm.
2. Support optimization: The spacing between support structures should be ≤1.5m to prevent excessive deflection of the prefabricated panels due to large spans. Steel supports require anti-rust treatment, while concrete supports need to have pre-drilled connection holes.
3. Installation accuracy control: Use a level and total station to calibrate the horizontal and vertical alignment of the prefabricated panels, with a deviation ≤3mm. After installation, check the width of the panel joints to ensure uniformity.
4. Waterproofing enhancement: Add an additional waterproof layer at the corners of the eaves, with a membrane overlap width ≥100mm. The sealant should be filled flush with the panel surface to prevent water accumulation and corrosion.

III. Pre-construction Preparation Points

1. Technical preparation: Deepen the design drawings to clarify the connection node details; organize technical briefings to ensure construction personnel are familiar with the process flow.
2. Material inspection: Verify the concrete strength report of the prefabricated panels and the welding quality of the steel reinforcement mesh. Connection materials must provide certificates of conformity and inspection reports.
3. Site conditions: Clean the base surface of floating mortar and debris, repair honeycombs and pits; set up a component storage area and harden the ground to prevent deformation of the prefabricated panels.

By strictly controlling design parameters, material quality, and construction details, the efficiency and reliability of eaves prefabrication can be achieved, extending the service life of the building.