How to Prevent Leaks in Prefabricated House Slabs
Preventing leaks in prefabricated house slabs requires a combination of structural repair and composite treatment of the waterproof layer, with core steps including crack pretreatment, epoxy resin filling, hemp fiber reinforcement, cement-epoxy mortar smoothing, and fiber cloth reinforcement. If trenching is not possible, an overall repair is needed.
1. Crack Pretreatment
Excavate a groove 4-6 centimeters deep along the slab joints of the prefabricated slabs, with the width adapted to the actual size of the cracks to ensure accommodation of subsequent filling materials. After excavation, thoroughly clean the groove of floating dust, loose concrete, and debris to avoid residual impurities affecting the bonding effect. Ensure the groove is dry and free of oil after cleaning, which can be achieved through natural air-drying or with the assistance of a hot air blower, providing a clean and stable base for subsequent material filling.
2. Epoxy Resin Filling
Prepare epoxy resin material and uniformly apply it to the inner walls of the cracks, forming a preliminary bonding layer 0.5-1 millimeter thick. Epoxy resin, with its high strength and corrosion resistance, can penetrate into the micro-pores of the concrete, enhancing the bonding force between the cracks and subsequent filling materials, preventing the repair layer from detaching. Ensure complete coverage of the inner walls of the cracks during application to avoid missed spots that could lead to waterproofing failure.
3. Hemp Fiber Reinforcement
Layer hemp fibers soaked in epoxy resin into the cracks, compacting each layer to expel air and avoid void formation. Hemp fibers, as reinforcing materials, can enhance the tensile strength of the crack filling, preventing re-cracking due to structural deformation. Reserve a 2-3 centimeter sealing space when filling to provide operational allowance for subsequent cement-epoxy mortar filling.
4. Cement-Epoxy Mortar Smoothing
Mix cement and epoxy resin in a 3:1 ratio to prepare cement-epoxy mortar. Fill the remaining cracks with the mortar in layers, controlling each layer's thickness to 1-2 centimeters, and compact and smooth it with tools to ensure dense filling. The final surface should be slightly higher than the original slab surface by 1-2 millimeters, providing a flat base for subsequent fiber cloth reinforcement and compensating for potential depressions due to material shrinkage.
5. Fiber Cloth Reinforcement
Cut oil-free glass fiber cloth and cover the repaired area's surface, securing it with epoxy resin or a special adhesive. Glass fiber cloth can enhance the toughness of the waterproof layer, resisting stress generated by minor structural deformations and preventing crack propagation. Ensure complete adhesion between the fiber cloth and the slab surface without wrinkles or bubbles, extending the edges to the healthy slab surface by 5-10 centimeters to form a continuous waterproof barrier.
Special Case Handling
If trenching to block cracks is not possible due to structural constraints, be aware of potential water seepage between prefabricated slabs. In this case, an overall repair of the entire slab or adjacent slab areas is necessary, rather than just treating local cracks, to prevent water penetration through unrepaired areas. When performing an overall repair, expand the treatment scope and synchronously treat surrounding slab joints according to the above steps to ensure waterproofing effectiveness.
