How to prepare openings for window on the construction site?

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A fundamental element of installing windows or gates is preparing the fitting area beforehand. Here’s a step-by-step guide:

Step 1: The reveal must be cleaned of any loose building materials. Ensure the surface is smooth and even, filling any defects with the appropriate mortar.

Step 2: Reinforce the reveals with a primer to ensure proper adhesion of sealing materials.

TIP: For ceramic blocks, sealing the horizontal part of the recess is crucial, as it prevents future ventilation and ensures better sealing (use mesh + mesh adhesive).

When applying external sealing, such as vapor-permeable window tape, ensure the external wall surface is level to guarantee proper adhesion of the tape.

Step 3: Maintain the correct expansion gap, which depends on the type of installation and recess. This gap should not exceed 30 mm; too small gaps may deform the profile and hinder window operation, while too large gaps weaken the window’s mounting.

Step 4: For terrace, sliding, and balcony windows mounted flush with the floor level, create a foundation or use system extensions. For thermal sub-window materials like warm sills or thermal sub-frames, level the reveal.

Step 5: Consider using a recessed lintel to allow insulation at the height of a concealed roller shutter box, if planned.

IMPORTANT: The installation conditions must be addressed at the design stage. Proper preparation will prevent issues with window selection later, when the walls are already in place.