Prefabricated Slab House Foundation Construction

The foundation construction of prefabricated slab houses requires special attention to four key aspects: foundation treatment, moisture-proof treatment, base treatment, and prefabricated slab installation. The specific steps and precautions are as follows:

1. Foundation Treatment
The foundation is the core basis for the stability of the house, and an appropriate plan must be selected based on geological conditions. In areas with soft soil or heavy rainfall (such as Anyue), it is recommended to adopt a pile foundation structure: drive in 16 piles with a diameter of 50 cm to a depth of 3.5 meters and use C30 commercial concrete for pouring to enhance the bearing capacity and reduce the risk of settlement. If the geological conditions are good, conventional foundation backfilling can be used, but attention should be paid to the selection of backfill materials: clean plain soil must be used, and the inclusion of construction waste, sharp stones, or organic matter should be avoided to prevent puncturing the moisture-proof layer or causing uneven settlement of the foundation. After backfilling, it should be compacted in layers, with each layer not exceeding 30 cm in thickness, and the compaction coefficient should meet the design requirements.

2. Moisture-Proof Treatment
Moisture-proofing is crucial for extending the service life of the house and should be approached from both material and structural aspects.

• Laying Moisture-Proof Film: After the foundation is backfilled, compacted, and leveled, lay a high-density polyethylene film (PE film or geotextile) with a thickness of ≥0.15 mm. The overlap width between films should be no less than 15 cm, and the seams should be repeatedly pasted with waterproof tape 3-5 times to ensure airtightness. A 10 cm thick concrete cushion or floor should be poured on top of the moisture-proof film to form double protection.
• Prefabricated Slab Elevated Layer: Set up an elevated layer of prefabricated slabs on the ground ring beam, with the cavity height controlled between 30-50 cm, utilizing the principle of air circulation to dissipate underground moisture. If the environmental humidity is high, ventilation holes (with a diameter of 5-10 cm) can be reserved under the prefabricated slabs to further enhance the moisture-proof effect.

3. Base Treatment
The flatness of the base directly affects the installation quality of the prefabricated slabs. Before lifting, the top of the wall should be moistened with clean water to prevent rapid water loss from the cement mortar, which could result in poor adhesion; then, use high-grade cement mortar (such as M15) to level the top of the wall, with a thickness controlled between 2-3 cm and a surface flatness error of ≤5 mm to ensure the stable placement of the prefabricated slabs. If there are cracks or loose parts on the top of the wall, they should be repaired in advance and cured until the strength meets the standard.

4. Prefabricated Slab Installation
The installation process requires strict control over the quality of support and connection.

• Slab Bottom Support: After the prefabricated slab is in place, temporary supports (such as wooden wedges or steel brackets) should be set up within 10 cm of the slab end to prevent the slab bottom from bending or cracking due to its own weight or construction loads during the installation process. Before pouring concrete into the slab joints, check whether the supports are stable.
• Slab Joint Treatment: The width of the slab joints should be controlled between 3-5 cm. First, fill the joints with cement mortar to two-thirds of the slab thickness, then insert short steel bars (with a diameter of 8-10 mm and a spacing of 30 cm) to enhance the connection, and finally pour micro-expansion concrete densely. The surface of the slab joints should be smoothed and polished to reduce the risk of future cracking.