How to Construct Stairs for Prefabricated Slab Houses

The construction of stairs (prefabricated stairs) for prefabricated slab houses should follow a standardized process, with specific steps outlined as follows:

1. Leveling Treatment

Apply a 20-millimeter-thick layer of C20 fine aggregate concrete mortar for leveling at the upper and lower openings of the stair sections on the stair beams, ensuring that the flatness error of the base layer does not exceed 3 millimeters. If the stair landing is a cast-in-place corbel structure, use M20 cement mortar for leveling to prevent stress concentration or hollowing issues after stair installation due to an uneven base layer. The leveling layer should be adequately cured, and the next construction step can only proceed after its strength meets the design requirements.

2. Pre-lifting Preparations

• Component Inspection: Verify the consistency between the prefabricated stair numbers and the construction drawings. Check the component surfaces for cracks, honeycombs, and other defects. Ensure that the stairs are in a horizontal position to prevent breakage during lifting due to tilting.
• Positioning and Layout: Mark the horizontal elevation lines and the position lines for the first step on the stair landing in advance, with an error controlled within ±2 millimeters.
• Placement Point Setup: Select 2-millimeter-thick, 50mm×50mm steel plates as placement points. Place two such plates on each of the upper and lower stair beams. Use a level gauge to calibrate the elevation, ensuring that the contact surface between the steel plates and the stair beams is flat to prevent excessive local pressure.

3. Lifting Operations

• Equipment Selection: Use a tower crane or large lifting equipment, equipped with dedicated steel wire rope slings. Connect firmly to the pre-embedded lifting rings on the stairs through universal swivel rings, ensuring that the lifting points are symmetrically distributed to prevent component distortion.
• Lifting Control: Slowly lift the stairs to a position 1 meter above the operating surface and pause. Operators should steady the stairs and align them with the control lines before slowly lowering them onto the stair beams, maintaining the component's level throughout the process to prevent collision with the structure.

4. Positioning and Adjustment

After the stairs are basically in position, use a crowbar to fine-tune them to the design position, focusing on calibrating the stair axis, elevation, and perpendicularity. The error should comply with regulatory requirements (e.g., perpendicularity deviation ≤ 3 millimeters). During adjustment, prohibit unrelated personnel from approaching to prevent overturning accidents.

5. Calibration and Fixing

• Calibration: Recheck the stair position using a laser level gauge or plumb line to ensure tight connection between the upper and lower stair sections.
• Fixing: Use high-strength non-shrink grout for injection fixing. Clean the injection holes in advance and fill them gradually from the low to the high points during injection to ensure dense and void-free grout.

6. Filling and Finished Product Protection

• Gap Treatment: Fill the gaps between the stairs and stair beams with polyethylene rods and block the bottom with polystyrene boards to prevent rainwater leakage.
• Protection Measures: After construction, cover the stairs with plastic film or colored strip cloth to prevent trampling or impact from heavy objects. The curing period should be no less than 7 days to ensure that the grout strength meets the standard.

Construction Key Points: All steps should strictly follow the design drawings. Material quality should comply with national standards, and operators should be certified to ensure construction safety and structural durability.