Optimal Slab Hole Dimensions for Internal Stairs

When planning the installation of an internal staircase, one of the most important considerations is the size of the hole in the attic . This hole must be large enough to accommodate the ladder , but at the same time it must not compromise the structural integrity of the attic. The exact size of the hole depends on the type of ladder and its specific dimensions .

Hole dimensions for open or straight stairs:

For straight stairs, the hole in the attic must be equal to the size of the staircase or slightly smaller. For example, if your ladder is 3 meters long and 85cm wide, the cutout should be approximately 251cm x 91cm to allow for secure mounting and space for finishes.

Hole dimensions for Spiral Stairs:

These ladders require a circular or square hole in the attic. The diameter or width of the hole should be at least equal to the diameter of the staircase plus additional allowance for installation and finishes. For example, for a spiral staircase with a diameter of 120 cm, a hole of at least 125 cm in diameter should be considered.

Hole dimensions for space-saving stairs:

These ladders, given their compact dimensions, may require smaller holes. However, it is essential to consider both walking space and safety regulations. A 137cm x 67cm opening is ideal for a 12-step straight staircase to reach a total height of 300cm

Additional Considerations:

In addition to size, it is important to consider the location of the hole in relation to the existing structure, the attic beams, and the surrounding spaces. It is recommended that you consult a structural engineer or architect to ensure that the hole does not compromise the safety and structural integrity of the building.

Local Regulations:

It is essential to comply with local building codes regarding attic openings and internal stairways. These regulations may vary by location and may impose specific requirements for size, safety and accessibility.

In conclusion, determining the appropriate attic hole size for an interior staircase requires careful consideration of the type of staircase, specific dimensions, existing structure, and local codes. For more information contact us privately