Concrete Prefabricated House Foundation

The concrete prefabricated house foundation needs to incorporate moisture-proof design and the characteristics of prefabrication technology. Common solutions include laying moisture-proof membranes or creating prefabricated slab elevated floors, while also paying attention to the differences from traditional cast-in-place foundation types.

I. Moisture-Proof Solutions for Rural Self-Built Houses

In rural self-built houses, moisture-proofing is a key issue for prefabricated assembled house foundations, with two mainstream methods currently available:

1. Laying Moisture-Proof Membranes

   • Principle: High-density polyethylene film (PE film or geotextile) is used to block the penetration of underground moisture.
   • Construction Steps: After backfilling and compacting the foundation, first lay a fine sand and gravel leveling layer, then cover it with a moisture-proof membrane (ensuring the film is undamaged), and finally pour a 10-centimeter-thick concrete cushion to secure the film.
   • Advantages and Disadvantages: It is low-cost and simple to construct, but its durability is affected by the quality of the film, the cleanliness of the backfill (avoiding sharp objects that could puncture it), and the sealing of the overlaps. Long-term use may lead to moisture-proof failure due to aging or construction defects.

2. Creating Prefabricated Slab Elevated Floors

   • Principle: A 30-50 cm cavity is reserved between the ground beam and the floor, physically isolating moisture and preventing underground moisture from directly contacting the indoor floor.
   • Construction Steps: After pouring the ground beam, compact the backfill to a height of 30-50 cm from the floor, then lay prefabricated slabs to form an elevated floor, and finally pour concrete on top for the floor.
   • Advantages and Disadvantages: The moisture-proof effect is more durable, but it requires additional space and has higher requirements for the load-bearing capacity of the ground beam, resulting in slightly higher construction costs compared to the moisture-proof membrane solution.

II. Differences Between Traditional Cast-in-Place Concrete Foundation Types and Prefabricated Foundations

Traditional cast-in-place concrete foundations are divided into three types based on structural form, but they differ in technical approach from prefabricated assembled house foundations:

1. Isolated Foundation: Suitable for low-rise buildings, it disperses loads by expanding the base area, but requires on-site formwork and pouring, differing from the industrialized production mode of prefabricated components.
2. Raft Foundation: Used for segmented construction of ordinary residential buildings, it forms a continuous slab foundation through integral pouring, while prefabricated foundations mostly use modular assembly for higher construction efficiency.
3. Box Foundation: Adopted for super high-rise buildings, it requires high-grade concrete and strict curing, which does not align with the lightweight and rapid installation characteristics of prefabricated foundations.

Summary: For concrete prefabricated house foundations, priority should be given to selecting moisture-proof membrane or elevated floor solutions to address moisture issues. At the same time, it is essential to clarify the differences from traditional cast-in-place foundations in terms of construction methods and applicable scenarios to avoid confusion in technical approaches.