Application
Stairwell Openings in Concrete Floors
Cutting large rectangular floor openings for new stairs, mezzanines, and vertical access through elevated slabs.
Adding a stair between floors, opening a mezzanine, or creating vertical access through an elevated slab means cutting a large rectangular opening in a structural floor. This is heavy, high-stakes work: the slab is usually reinforced or post-tensioned, the opening changes how loads travel, and the removed section can weigh thousands of pounds.
Crews we route work to cut stairwell openings only from an engineered opening detail that specifies edge reinforcement, shoring, and any new supporting beams. The opening is then cut in controlled sections that can be safely rigged and lowered, not dropped.
Cutting a floor opening
The opening perimeter is cut with slab sawing; for thick or heavily reinforced slabs, wire sawing removes the section cleanly. Adjacent wall openings for the stair enclosure use wall sawing, and the removed slab is handled as slab removal or structural concrete removal.
Because these are structural cuts, concrete scanning maps post-tension tendons and rebar so the opening and any temporary cuts avoid critical steel — essential in Houston's post-tension mid-rise floors.
Practical considerations
- An engineered opening detail with edge reinforcement and shoring must be in hand before cutting.
- Cut sections are rigged and lowered in controlled pieces sized to the available lift and access.
- Wet-cutting and slurry control keep silica dust within OSHA 1926.1153 limits on occupied floors.
- The floor below is protected and access is staged so removed pieces exit the building safely.
Engineered openings only
Cutting a hole in a structural floor changes load paths. No stairwell opening should be cut without an engineered detail and shoring plan.
Stairwell opening FAQs
- Can you cut a stair opening in an elevated slab?
- Yes, working from an engineered opening detail. The slab is scanned, the perimeter cut with slab or wire sawing, and the section removed in controlled pieces.
- How is the heavy cut section removed?
- The section is cut into manageable pieces that are rigged and lowered rather than dropped, sized to the lift and access available on site.
- Why is scanning critical for floor openings?
- Elevated slabs are often post-tensioned. Scanning locates the tendons so the opening and any relief cuts avoid severing a stressed cable.
- Do I need an engineer for this?
- Yes. A structural engineer specifies the opening, edge reinforcement, and shoring before any cutting begins.
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