Lishui Prefabricated Houses

Lishui prefabricated houses mainly include integrated houses (modular prefabricated houses) and the renovation of prefabricated panel buildings. Details are as follows:

Integrated Houses (Modular Prefabricated Houses)

1. Product Details
   • Structural Design: The main structure adopts high-strength galvanized steel structures, such as G550 or Q345B grade steel. The components undergo hot-dip galvanizing anti-corrosion treatment, with a rust-proof capability of over 20 years. Module beams, columns, and purlins are precisely processed in the factory, with dimensional errors controlled within ±1mm. The overall structure can withstand an intensity of 8 degrees on the seismic fortification intensity scale and typhoons of up to Category 12.
   • Factory Prefabrication Process: All modules complete the pre-installation of walls, doors, windows, water and electricity pipelines, and even interior decoration in the factory. The walls use composite sandwich panels, with common core materials including polyurethane (PU), rock wool, or EPS polystyrene. Rock wool panels have Class A fire-resistant performance, with a fire resistance limit of 1 - 2 hours; polyurethane panels have the best thermal insulation performance, with a thermal conductivity as low as 0.024W/(m·K).
   • Modular Installation Process: Foundation preparation takes 1 - 2 days, involving on-site pouring of concrete strip foundations or prefabricated concrete piers. Module lifting takes 1 - 3 days, using truck cranes to lift module units onto the foundations in sequence, connecting them with high-strength bolts and filling with sealing strips. Connection and finishing take 1 - 2 days, involving connecting pre-buried water and electricity pipelines, installing roof covers, exterior wall decorative panels, and waterproofing the joints.
2. Application Scenarios and Industry Standards: Widely used in various scenarios such as temporary offices, worker dormitories, post-disaster resettlement, tourist homestays, and small commercial facilities. The design must comply with the "Technical Standard for Prefabricated Steel Structure Buildings" GB/T 51232 - 2016 and the "Code for Design of Steel Structures" GB 50017 - 2017. In mountainous areas like Lishui or regions frequently affected by typhoons, special emphasis is placed on wind resistance and drainage design, such as using roofs with a slope of ≥10% and installing drainage gutters.
3. Selection and Precautions: Ensure that the thickness of the galvanized layer on the steel is ≥275g/m², and the fire-resistant grade of the wall panel core material reaches Class B1 or above. Pay attention to the heat transfer coefficient (K-value) and airborne sound insulation (RW-value) of the wall panels. Choose manufacturers that offer a 5-year factory warranty and a 20-year design life for the steel structure.

Renovation of Prefabricated Panel Buildings

The Liandu District of Lishui City has conducted a comprehensive investigation and renovation of prefabricated panel buildings, which started in May 2022. A total of 3,410 buildings with potential safety hazards were identified. According to regulations, a safety inspection of buildings is conducted every 5 years, and a new round of inspections is expected to be carried out before 2027. At the same time, regular grid patrols are conducted, and the Internet of Things technology is used for real-time monitoring of dilapidated buildings with safety hazards. Classification and treatment measures include exploring solutions such as state-owned enterprise repurchases and incorporating them into urban organic renewal projects.