Creating stairwell openings — safe structural openings
Stairwell openings in concrete, timber or steel-joist floors, with trimmer frame and propping.
Creating a stairwell means opening a floor for a staircase without weakening the rest of the structure. The joists or reinforcement that are cut are picked up by a trimmer frame designed by the structural engineer.
Opening a floor without compromising the structure
Creating stairwell openings — a well-controlled structural operation
An opening interrupts load-bearing elements: joists in a timber floor, beams or reinforcement in a concrete slab. Their load is transferred to a trimmer frame, made of steel sections or reinforced concrete, which carries it to the adjacent walls or beams. The floor is propped before cutting, by diamond sawing for concrete.
The size of the opening is set by the staircase: its length determines the headroom above the treads, for which good practice recommends at least 2 m. In a co-owned building, the floor is usually a common part: the works go to the general meeting, with the structural calculation.
What a stairwell requires
Every opening is sized by a structural calculation.
Trimmer frame
Steel or reinforced concrete frame that picks up the cut elements.
Propping
The floor is supported before and during cutting.
Diamond sawing
Clean cutting of the concrete slab, without shock to the structure.
Headroom
The length of the opening leaves about 2 m of clearance above the treads.
Timber or concrete floor
Joists, solid slab, beam-and-block, jack-arch floor.
Co-owned buildings
General meeting approval when the floor is a common part.
Our expertise
Know-how in special works
We create stairwell openings in existing floors, from propping to the trimmer frame, following the structural engineer’s calculation.
- Creating stairwell openings
- Cutting floors and slabs
- Structural strengthening
- Load transfer
- Work on existing structures
How a Sirianni Travaux project unfolds
Survey and calculation
Floor structure, staircase dimensions, trimmer frame calculation.
Propping
Props installed beneath the floor concerned.
Trimmer and cutting
Installation of the trimmer, then sawing or removal of the section to open.
Finishing
Edges made good and props removed after inspection.
Frequently asked questions
What is a stairwell opening?
Can a stairwell be created in an existing building?
How big should the opening be?
Is approval needed?
Is strengthening needed?
Related services
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Strengthening timber, concrete and steel-joist floors: change of use, sagging floors, renovation.
ViewStructural strengthening
Strengthening existing structures: foundations, floors, load-bearing walls, before renovation or an extra storey.
ViewConcrete & masonry repair
Repair of damaged concrete and masonry: corroded reinforcement, cracks, joints, old walls.
ViewShall we take a closer look at your project?
From first contact to quote, you speak directly with the people who will carry out the works — precise, concrete, straightforward.