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Diamond core drilling · Essex & London

Floor & Slab Core Drilling

Vertical cores through concrete floors and slabs for soil stacks, drainage, risers and M&E services, so pipes and cables can pass cleanly from one floor to the next.

Get a quote Call 07776 144737
Core drill rig with a large bit drilling vertically through a floor inside a timber frame

What it is

Drilling through a concrete slab, cleanly

When a pipe, duct or cable has to pass from one floor to the next, it needs a hole through the floor slab. Diamond core drilling cuts that hole as a clean cylinder: a hollow, diamond-tipped bit grinds down through the concrete and the core comes out as a solid plug, leaving a neat round hole with smooth sides.

For floors the drill is mounted on a vertical rig stand, which holds the bit plumb and steady. That matters when the hole has to come out in the right place on the ceiling below. Rigs are normally fixed to the floor with an anchor, but on finished floors where you don’t want a fixing hole, a vacuum-base rig can be held down by suction instead.

When you need it

You’ll need a core through a floor for new soil and waste stacks, drainage, M&E risers, sprinkler pipes, HVAC and condensate pipework, and cable routes. It comes up in refurbishments, fit-outs and extensions, wherever services have to be added to an existing building.

Reinforced slabs

Most concrete floors and slabs contain steel reinforcement. A diamond bit cuts through it, but cutting reinforcement can affect the structure, so on structural slabs the hole positions are usually checked by an engineer first. If you have drawings or an engineer’s mark-up, send them with your enquiry.

Need something bigger than one core, or a square or rectangular hole? That’s done by stitch drilling an opening in the slab.

Applications & materials

What floor cores are for

Typical applications

  • Soil and waste stacks
  • Drainage
  • M&E risers and service penetrations
  • Sprinkler and fire services
  • HVAC and condensate pipework
  • Cable routes between floors

Materials

  • Concrete floor slabs
  • Reinforced concrete, including roof slabs
  • Concrete with a screed or floor finish on top
Core drill rig on an orange base plate drilling vertically through a concrete floor inside a timber frame
Vertical coring through a concrete floor.
Vertical core drill rig at work on a painted concrete plant-room floor, with flue pipes alongside
A vertical rig at work on a painted plant-room floor.
Underside view of an opening through a roof slab, with metal deck ceiling and service pipes
Looking up through a slab from the space below.

How we do it

Water, slurry and the room below

Drilling down through a slab is usually done wet. Water cools the bit and flushes the ground concrete out as slurry. On a floor that water has two places to go: across the floor on top, and down the hole once the bit breaks through. Both need managing.

On top, water is collected around the bit and picked up with a wet vac as the drilling goes. Underneath, the area below the hole needs to be clear and protected, because the core can drop free at breakthrough along with any water left in the cut. That means someone needs to be able to get into the room or void below.

The rig is set up over the marked position and levelled so the bit runs plumb. On a thick slab the core may come out in sections rather than one piece.

Before we price it

What we need from you

Send these through the quote form and we can price the job properly.

  • Photos of the floor from above, and of the ceiling below if you can get them
  • Hole sizes and positions, or the drawing they’re marked on
  • The slab thickness and build-up, if you know it (for example screed on concrete)
  • Whether an engineer has approved the positions on a structural slab
  • What’s directly underneath, and whether we can get into that space
  • Access: stairs or lift, and how far it is from parking
  • Whether there’s power and water near the work area

Good to know

Questions people ask

Will water come through the ceiling below?

The risk is at the moment the bit breaks through, when water in the cut can run down the hole. That’s why the space below should be cleared and protected before drilling, and why water is collected on top as the drilling goes.

Can you drill through reinforced concrete?

Diamond bits cut through concrete and steel reinforcement. The real question is usually whether you should: on structural slabs, check the positions with your engineer first so the cores don’t cut through critical bars.

What if I need a square opening?

A square or rectangular opening is formed from a line of overlapping cores. See forming openings by stitch drilling.

Other services

More of what we drill

Need to drill through a slab?

Send us photos from above and below, plus the hole sizes or drawing. We’ll come back to you with a price.

Get a quote Call 07776 144737