Evaluation Criteria for Wooden Prefabricated Houses
The evaluation of wooden prefabricated houses should be conducted comprehensively from six dimensions: structural safety, connection nodes, component conditions, material properties, functional suitability, and maintenance costs. The specific criteria are as follows:
1. Structural Safety Assessment
According to the "Standard for Dangerous Building Appraisal" (JGJ 125-2016), it is necessary to focus on testing the stability of core components such as foundations, walls, and beams and columns. For example, if the deflection of the main beam exceeds Lo/150 of the span or there are serious material defects in the tension zone (such as cracks or decay), and if the deflection of the roof truss exceeds Lo/120 and the nodes are decayed or split, these should be identified as dangerous points. Such issues directly affect the overall load-bearing capacity of the house and are the primary indicators for safety assessment.
2. Reliability of Connection Nodes
Check whether the connection methods comply with design specifications, with a focus on whether the nodes are loose, deformed, slipped, or if the iron parts are rusted. For example, check if bolt connections are loose, if mortise-and-tenon joints are cracked, or if metal connectors are rusted through. If structural looseness occurs due to connection failure, it should be immediately rated as a dangerous point to avoid the risk of overall collapse caused by local failure.
3. Degree of Component Damage
Other wooden components must meet specific deformation and damage thresholds: if the deflection of the joist exceeds Lo/120, if the lateral deflection of the wooden column is greater than h/150, or if the decayed area of the column base exceeds 1/5 of the original cross-section, these fall within the dangerous category. In addition, components with a slope of the grain exceeding the specified value (e.g., >7% for tension members) or those with heart rot (internal decay) should also be prioritized for inspection due to their significantly reduced mechanical properties.
4. Material Properties and Compliance
If engineered wood such as LVL (Laminated Veneer Lumber) is used, its static bending strength, modulus of elasticity, durability, and environmental indicators need to be tested. For example, LVL beams and columns used in building structures must meet high mechanical performance requirements (e.g., bending strength ≥35MPa), while LVL used for concrete formwork should focus on surface flatness and wear resistance. At the same time, materials must comply with environmental standards (e.g., formaldehyde emission ≤0.5mg/L) to avoid long-term health impacts from use.
5. Functional Suitability
Evaluate functional completeness based on the usage scenario: scenic spot or homestay projects should focus on custom design capabilities (e.g., spatial layout, appearance style); projects requiring rapid construction should assess the standardization level of prefabricated modules (e.g., module dimensions, compatibility of connection interfaces); projects with limited budgets should balance material quality and cost to avoid a significant increase in later maintenance costs due to excessive pursuit of low prices.
6. Maintenance and Relocation Costs
The evaluation should include long-term maintenance costs (e.g., frequency of anti-corrosion treatment, coating renewal cycles) and relocation feasibility (e.g., whether modular design facilitates disassembly and assembly). For example, while high-end custom wooden houses offer excellent quality, they have longer construction periods and higher costs; standardized prefabricated houses, although having lower initial costs, may have limited functional expandability due to design generality. Economic efficiency should be comprehensively evaluated based on the project lifecycle.
