How to Renovate a Prefabricated Slab House

Renovation of a prefabricated slab house requires targeted treatment based on different renovation stages and needs, as detailed below:

Wall Renovation

• Skim Coating: The surface of prefabricated slabs is relatively flat but may have minor pores, mold release agent residues, or slight cracks. Additionally, the low water absorption rate of the concrete surface affects the adhesion between the skim coat and the substrate. Direct skim coating may result in issues such as peeling, cracking, or blistering of the skim coat layer. Therefore, surface preparation is necessary before skim coating:
  • Surface Inspection and Cleaning: Inspect the surface condition, sand or wire brush uneven areas, and clean the surface of dust, oil, and mold release agents using water or a specialized cleaning agent.
  • Gap Filling: The joints between prefabricated slabs should be treated with a specialized filler to ensure dense filling and prevent future cracking.
• Tiling: When tiling the walls of a prefabricated slab house, horizontal grooving is strictly prohibited during the plumbing and electrical work. Since prefabricated slabs are hollow, a 5 cm deep horizontal groove can damage the slab structure, reduce load-bearing capacity, and pose safety risks.

Floor Renovation

For prefabricated slab houses that have been in use for a certain number of years, if you want to lay floor tiles directly, the original prefabricated slabs must be reinforced. Using prefabricated slabs as floor slabs poses safety risks, as the steel bars used are thin and mostly straight without crossbars. The larger the span, the greater the elasticity and the higher the risk, and there may also be sagging. Laying floor tiles directly after a certain number of years of use can accelerate slab aging, leading to issues such as softening, bulging, and cracking of the floor tiles. There are two reinforcement methods:
- Traditional Reinforced Concrete Reinforcement: Add two small beams under the prefabricated slabs, with the beams forming a cross shape with the slabs. Drill holes in the slabs and pour concrete using grouting to enhance the load-bearing capacity of the slabs.
- Steel Beam Reinforcement: Provide internal support in the house, measure and mark the positions for steel beams on both walls, and use materials to support the steel beams so that their surfaces are fully in contact with the bottom of the prefabricated slabs, improving slab stability.

Ceiling Renovation

• Adjusting Wood Strip Height: After installing all wood strips, adjust their height. Since the height of each beam in the house varies, use the wood strips to ensure that the final height for installing gypsum boards is on the same plane, preventing gypsum board cracking.
• Wiring: Another purpose of installing wood strips is for wiring. Wires should bypass the beam positions and can pass through the gaps between the wood strips after installation. Since the height of the wood strips is 20 mm, wires can easily fit through these gaps.
• Adjustment Method: First, use two wooden boards as supports and nail them to an interior wall. Place a level on top, which will emit a laser ring in a 360-degree direction. First, find the lowest point of all wood strips in the room, then adjust the other wood strips downward to the same height. Be cautious with adjustment tools; do not use an impact wrench as its high speed and power can easily over-adjust. Instead, use a slower electric screwdriver, place a ruler against the screw position, and adjust according to the laser marking on the ruler.