How to Construct the Exterior Walls of a Prefabricated House

The construction of exterior walls for prefabricated houses requires special attention to the installation process, waterproofing design, and construction techniques. The specific steps are as follows:

I. Installation Process

1. Positioning and Elevation Control: Mark the positioning edge lines of the prefabricated exterior walls on the floor slab. After cleaning the floor, place elevation control shims for the wall panels. Adjust the elevation using these shims to ensure a level foundation.
2. Lifting and Positioning: Use a tower crane to lift the exterior wall panels. Pause when the bottom of the panel reaches 60 cm above the ground for subsequent operations. During installation, strictly control accuracy by setting reference and positioning lines, and adjust the panel position through coarse and fine adjustments, with a deviation generally not exceeding 5 mm.

II. Waterproofing Design Concept

1. Concept Shift: The traditional 'water blocking' concept has gradually been phased out due to the challenges posed by the numerous joints in prefabricated exterior walls and the mobility of some wall panels, which make waterproofing difficult. Modern design adheres to the principle of 'water diversion is better than water blocking, and drainage is better than waterproofing,' aiming to discharge infiltrated water outdoors through reasonable drainage paths.
2. Specific Measures:
   • Joint Design: Design the wall panel joints as a tongue-and-groove shape with the inner side higher than the outer side, combined with pressure relief cavities to prevent water from flowing backward.
   • Material Application: Use rubber waterstops and multi-component weather-resistant waterproof adhesives to enhance the waterproofing system and improve joint sealing.

III. Joint Waterproofing Construction Forms

1. Internally Cast and Externally Hung Prefabricated Exterior Wall Panels (PCF Panels): The exterior side adopts drainage cavities and caulking, while the interior side relies on the self-waterproofing of cast-in-place concrete. This method is simple in construction but difficult to control waterproofing quality, as the cavities are prone to clogging.
2. Externally Hung Prefabricated Exterior Wall Panels: Adopt a closed-line waterproofing form, which requires higher technical standards to ensure tight joint sealing.

IV. Construction Technique Highlights

1. Pre-construction Inspection:
   • Inspect the geometric dimensions, flatness, surface concrete density, and through-cracks of the wall panels. Do not use unqualified panels.
   • Check the installation quality of the pre-embedded rubber strips to ensure they are secure and undamaged, preventing concrete slurry from leaking in and hardening the rubber strips.
2. Joint Pre-treatment:
   • Defect Repair: Clean the area around the defect, apply an interface agent, and repair it flat with a 90-degree edge.
   • Joint Cutting: For joints less than 10 mm wide, use mechanical cutting to reach the design standard width (minimum 10 mm).
   • Step Grinding: Use an angle grinder to smooth out any steps near the cross joints.
3. Construction Process:
   • Prepare tools (sealant, caulking gun, scraper, etc.) → Clean the construction surface → Fill in backing material → Apply masking tape → Prime the surface → Fill with sealant → Trim the joints → Post-treatment.
   • Before applying the sealant, clean the base layer and reserved cavities with high-pressure air. Check the depth of the backing and ensure the thickness of the applied sealant meets the design requirements.