Application
Floor Drain Coring
Coring clean, sized openings in slabs for floor drains, cleanouts, and drain bodies in kitchens, baths, and process areas.
Floor drains and cleanouts need a clean round opening through the slab sized to the drain body and its connection. Whether you're adding a mop-sink drain in a back-of-house area, a floor drain in a restroom retrofit, or a process drain on a plant floor, the core has to align with the plumbing below and give room for the drain assembly.
Crews we route work to core these openings cleanly so the drain seats without chipping and grouting a rough hole. In Houston's slab-on-grade construction over expansive clay and frequent post-tension foundations, scanning before coring keeps the drain from landing on a tendon or a live line.
Coring method
Floor drain openings are made with concrete core drilling, sized to the drain body and the pipe below. Where the drain connects to a new under-slab line, the run is cut with slab sawing or trench cutting. Larger multi-drain projects often pair coring with trench drain installation.
Concrete scanning precedes coring on any structural slab to avoid post-tension tendons and rebar.
Practical considerations
- Core diameter is set to the drain body plus grout or clamp clearance.
- Wet coring controls silica dust per OSHA 1926.1153 and keeps finished floors clean.
- Alignment with the under-slab pipe is confirmed before coring so the drain connects cleanly.
- In post-tension slabs, the core location is scanned and adjusted to clear tendons.
Scan first in slab-on-grade
Post-tension tendons run through many Houston slabs-on-grade. A quick scan keeps a floor-drain core from becoming a structural emergency.
Floor drain coring FAQs
- What size core do I need for a floor drain?
- It depends on the drain body and connection. The crew sizes the core to the manufacturer's drain body plus the clearance needed to grout or clamp it in place.
- Can you core over an existing drain line?
- Yes, once the line is located. Scanning confirms the pipe position so the core aligns with the connection below.
- Is scanning always required?
- On structural slabs and post-tension slabs it's strongly recommended to avoid tendons and rebar. Non-structural toppings may not require it.
- How is water managed when coring indoors?
- Wet coring uses controlled water with vacuum recovery, so the area stays clean and silica dust stays within OSHA limits.
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