Prefabricated House Quality Appraisal Report

The core content of the prefabricated house quality appraisal report is to classify the structural safety of the house according to current standards and provide clear handling recommendations. Details are as follows:

I. Basis for Appraisal Grade Classification
According to the 'Standard for Appraisal of Dangerous Buildings' (JGJ 125-2016), the risk level of prefabricated houses is divided into four grades:

1. Grade A: The structural load-bearing capacity meets normal usage requirements, with no dangerous components. For example, a prefabricated slab building that has been inspected and found to have no defects in its load-bearing structure can be classified as Grade A and can continue to be used without reinforcement.
2. Grade B: There are individual dangerous components (such as exposed and corroded rebar in beams, unreliable connections between the roof and walls), but they do not affect the safety of the main structure. Such buildings need to be repaired and reinforced (such as rust prevention treatment, connection reinforcement) before continued use.
3. Grade C: Some load-bearing structures do not meet safety requirements, and local hazards have emerged (such as water leakage in the prefabricated slab floor, wall cracks that reduce seismic resistance). Structural reinforcement (such as adding supports, repairing cracks) should be prioritized to prevent the hazards from expanding.
4. Grade D: The overall load-bearing structure has failed, constituting a dangerous building as a whole (such as unreasonable structural design in the added area, brick columns that cannot bear the load). Such buildings need to be demolished or rebuilt on the original site to avoid the risk of collapse.

II. Core Basis and Methods for Appraisal
The appraisal report is technically supported by national standards such as the 'Technical Standard for Inspection of Building Structures' (GB/T 50344-2019) and the 'Code for Design of Concrete Structures' (GB 50010-2010). It evaluates the stability of the foundation and the overall safety of the building by conducting on-site inspections of cracks, deformations, and corrosion in load-bearing components. For example, a two-story prefabricated slab mixed-structure building was found to have significant safety hazards due to an unreasonable structure after adding an additional floor, and it was determined that rectification and reinforcement were required.

III. Key Considerations

1. No direct correlation between building age and appraisal results: The appraisal grade of a prefabricated slab building depends on the actual condition of the structure, not the year of construction. A large number of prefabricated slab residential buildings across the country have been evaluated as Grade A or B, with only a few Grade D dangerous buildings requiring demolition.
2. Equal emphasis on old renovation and hazard treatment: Most prefabricated slab buildings improve their living quality through old renovation (such as exterior wall renovation, pipeline replacement), but underlying hazards (such as insufficient seismic resistance, rebar corrosion) still require professional treatment to prevent minor problems from evolving into major risks.