Can I core a hole through a floor slab for a pipe?
Since 1 April 2025, a small opening for building services is an insignificant building work if the slab is not a cantilever slab, flat slab or prestressed element, the opening is no more than 150 mm across, and its centre is at least 450 mm from the edge of any existing opening. At-grade ground slabs are treated more leniently. Anything larger, or any opening in a flat or post-tensioned slab, needs a PE and BCA approval. Fire-stopping is still required if the slab is a compartment floor.
From the RRD Field Guide, checked against the sources cited in Hacking Walls and Slabs in Singapore: Structural Elements, PT Slabs and Household Shelters. General information, not advice for your project.
The fuller picture
In Singapore you may remove or open a wall without BCA submission only if it is genuinely non-load-bearing, meaning it carries nothing but its own weight. Openings in reinforced concrete walls, beams, columns or most slabs need a PE's structural plans and a BCA permit before work starts. Household and storey shelters must not be hacked; only limited drilling and finishes are allowed under SCDF's rules.
More questions on this topic
- How can I tell whether a wall is structural?
- Do I need BCA approval to hack a non-structural wall?
- Why are post-tensioned slabs so dangerous to core?
- Can I hack or modify my household shelter?
- What happens if structural works are done without a permit?
- Does a condo need to approve hacking inside my unit?
- Is scanning the slab enough before coring?