How to Open Windows in Prefabricated Slab Houses

Opening windows in prefabricated slab houses requires strict adherence to structural safety principles, with the core being to avoid load-bearing components and implement reinforcement measures. The specific steps are as follows:

I. Pre-construction Assessment

1. Confirm Wall Properties: By reviewing architectural drawings, using a rebar detector, or consulting a structural engineer, identify the locations of load-bearing walls, ring beams, structural columns, and main rebars in prefabricated slabs. It is strictly prohibited to open windows on these structures.
2. Reporting and Approval: Submit a window-opening application to the property management or relevant authorities. In some cases, a reinforcement plan must be provided and approved before construction can proceed.

II. Window Location Selection

1. Avoid Key Structures: The top edge of the window opening should be at least 10-15 cm away from the bottom of the floor slab, and the bottom edge should maintain a safe distance from the ground. The width of the window opening should not exceed one-third of the original wall width, and a lintel must be installed at the top of the window to distribute loads.
2. Prioritize Non-load-bearing Walls: Choose non-load-bearing walls for window openings. If a window must be opened in a load-bearing wall, structural calculations must be performed to verify safety.

III. Construction Process

1. Precise Positioning: Use a laser level to mark the window opening location, ensuring dimensions meet design requirements.
2. Gradual Demolition:
   • Cut grooves on both sides (depth 20-30 mm) and remove wall sections in blocks to avoid vibrations affecting adjacent structures.
   • If rebars are encountered, cut and retain them for subsequent reinforcement. Direct use of a sledgehammer for demolition is strictly prohibited, as it can easily cause wall cracks or collapse.
3. Structural Reinforcement:
   • Install chemical anchors or threaded rebars around the opening and weld them to the original wall rebars.
   • Formwork and pour C25/C30 micro-expansion concrete to create a reinforced concrete frame for enhanced load-bearing capacity.
4. Waterproofing Treatment:
   • Adopt a four-layer protection system of "waterproof mortar leveling - applying polymer waterproof coating - installing window frames - applying weather-resistant sealant".
   • Fill gaps with expanding foam to ensure airtightness between the window frame and wall.

IV. High-risk Operation Warnings

1. Curing Requirements: Newly poured concrete requires curing for 7 days (watering 2-3 times daily). Installation of window frames or subsequent construction is prohibited during the curing period to avoid affecting concrete strength.
2. Non-professionals Prohibited: Window opening in ordinary residential buildings should be performed by professionals. Unauthorized construction by non-professionals may compromise structural safety.

Special Note: For agricultural buildings such as prefabricated slab pigsties, electric window openers, automatic exhaust balls, or exhaust fans can be used on the roof, and cross-ventilation windows or tiered windows (such as roller shutter vents) can be designed on the sides, provided that the main load-bearing structure is not compromised.