Self-built House: Precast and Cast-in-place Slabs

In self-built houses, precast and cast-in-place slabs exhibit significant differences in construction methods, key performance, cost and schedule, applicable scenarios, and foundation moisture prevention, necessitating selection based on actual needs.

Construction Methods: Cast-in-place slabs require on-site formwork setup, steel bar binding, and concrete pouring, forming an integral structure after solidification, with a complex and lengthy construction process; precast slabs are prefabricated in factories and directly assembled on-site after transportation, offering high construction efficiency and suitability for rapid construction scenarios.

Key Performance:

• Seismic Resistance: Cast-in-place slabs, due to their integral pouring, have strong structural continuity and excellent seismic performance, meeting the specifications for high-rise buildings and earthquake-prone areas; precast slabs, being assembled structures, have low joint connection strength and weaker seismic resistance, suitable only for low-rise buildings.
• Waterproofing: Cast-in-place slabs are solid structures without gaps, providing outstanding waterproofing performance; precast slabs have honeycomb-like pores inside and are prone to water leakage at joints, requiring additional waterproofing treatment to prevent leakage issues on the top floor.

Cost and Schedule:

• Cost: Precast slabs have lower material and labor costs, with overall expenses approximately half of those for cast-in-place slabs; cast-in-place slabs require formwork, steel bars, concrete, and other materials, along with a long construction period, resulting in higher comprehensive costs.
• Schedule: Precast slab installation takes only a few days, while cast-in-place slabs require waiting for concrete solidification (about 28 days), significantly extending the construction period.

Applicable Scenarios:

• Cast-in-place Slabs: High-rise residential buildings, large-span spaces (such as shopping malls), bathrooms, and other areas requiring waterproofing and moisture prevention, as well as earthquake-prone areas or roof structures;
• Precast Slabs: Temporary buildings, low-rise rural houses, or projects with extremely tight budgets, but requiring strict joint waterproofing treatment to avoid leakage risks.

Foundation Moisture Prevention:

• Precast Slabs: Moisture prevention can be achieved through an elevated floor, i.e., reserving a 30-50cm cavity between the foundation and the ground to block moisture rise through air circulation, suitable for humid areas;
• Cast-in-place Slabs: No special moisture prevention design is mentioned, relying on foundation waterproofing layers or moisture-proof materials for treatment.

Summary: If structural safety, durability, and seismic and waterproofing performance are prioritized, cast-in-place slabs are the preferred choice; if the budget is limited, the construction period is tight, and the building is low-rise, precast slabs can serve as an alternative, but joint treatment and moisture prevention measures must be strengthened.