Concrete Prefabricated House Membrane

In rural self-built houses, the 'membranes' related to concrete prefabricated houses mainly include moisture-proof membranes and concrete curing membranes, which should be selected based on the construction stage and not confused.

1. Moisture-Proof Membrane: Key Material for Foundation Moisture Prevention

The core function of a moisture-proof membrane is to block underground moisture from permeating upwards through the concrete foundation, preventing indoor dampness or structural corrosion. Its application scenario is after foundation backfilling and compaction, and before pouring the concrete cushion, with the following specific steps:

• Material Selection: High-density polyethylene film (PE film or geotextile membrane) with a thickness of ≥0.15 millimeters should be used to ensure puncture resistance and durability. Inferior films are prone to damage, leading to moisture-proof failure.
• Construction Points:
  • The foundation surface should be flat, with a fine sand and gravel leveling layer laid first, followed by covering with the moisture-proof membrane;
  • Seams should be sealed with waterproof tape to prevent moisture from seeping through gaps;
  • Avoid sharp objects (such as stones, rebar heads) from puncturing the film; otherwise, local repairs or replacements are required.

If moisture-proof treatment is neglected, underground moisture may corrode rebar, cause wall efflorescence, and result in high repair costs later.

2. Concrete Curing Membrane: The 'Moisture-Retaining Layer' Ensuring Structural Strength

After concrete pouring, cement hardens through a hydration reaction, which requires continuous internal moisture retention. The function of a curing membrane is to lock in moisture and prevent cracking, with the following specific requirements:

• Coverage Timing: Cover immediately after the initial setting of the concrete (when there is no visible water on the surface) to prevent rapid moisture evaporation.
• Material Selection: Ordinary plastic film is sufficient, but it must fully adhere to the concrete surface to reduce air circulation.
• Curing Period: Depending on the ambient temperature and concrete strength grade, it should last 7-14 days. In low-temperature or dry environments, the curing time should be extended.

If the curing membrane is not covered in a timely manner, the concrete surface is prone to dry shrinkage cracks due to rapid moisture loss, reducing structural load-bearing capacity. Later repairs require chipping and repouring, with costs reaching hundreds of yuan per square meter.

3. Membranes Related to Prefabricated Components: Special Applications of Industrial Products

Some reinforced concrete prefabricated panels (such as assembled composite slabs and floor bearing slabs) may be equipped with non-removable bottom membranes. These membrane materials are produced integrally with the components and do not require on-site removal. However, they belong to the category of industrial products and differ in nature from moisture-proof membranes and curing membranes, with less involvement in rural self-built houses.

Summary: In rural self-built houses, moisture-proof membranes are used for foundation moisture prevention, and curing membranes are used for concrete moisture retention. The two functions are independent and irreplaceable. During construction, it is essential to strictly distinguish application scenarios, select compliant materials, and operate according to specifications to ensure the structural safety and durability of the house.