Core Drilling and Concrete Cutting, MacPherson Street, Cremorne

The job

Keks Projects is building a new multi level building on MacPherson Street in Cremorne, on Sydney's lower north shore. As the structure went up and the services went in, the job kept needing holes and openings in concrete that was already poured.

Perfect Concrete Care has been Keks' on call coring and cutting crew on the job since June 2025. We come in when an area is ready, do the cores, cuts and openings, and come back for the next lot. This page covers the work up to September 2026.

What we did

• Concrete scanning before coring, looking for post tensioned cables and reinforcement, with the positions marked on the slab
• Core drilling for services through walls and slabs, from small holes up to large barrels, most of them horizontal cores through walls
• Stitch coring rows of overlapping cores to form openings where a saw could not reach
• Concrete cutting of new openings in slabs, including curved cuts and areas cut into a grid so the pieces could be lifted out
• Sawing new doorways and tall openings through concrete walls, with the wall propped before cutting
• Coring from scaffold on the outside faces and working around the other trades inside

What made it hard

On call work on a live build means the crew rarely does the same thing two days running. One visit is a handful of cores for the plumber, the next is a new doorway or a slab opening. Each area has to be ready before we can start, and the scaffold and access sometimes have to change first: one August 2025 diary records a stand down while the scaffold was adjusted for the holes.

The slabs are post tensioned in places, so a core in the wrong spot is not an option. And a lot of the holes are horizontal cores through walls, drilled from scaffold or in tight corners where the rig has to be set up carefully.

How it was done

Where the slab could have cables, it was scanned first and every position marked before the rig went down. Cores were drilled wet with the slurry on a vacuum, and each one was measured against the size and depth the builder needed.

For openings, the cut lines were marked on the concrete to the size required. Walls were propped before a doorway was sawn out. Slab areas were cut into a grid of pieces small enough to lift, and where the saw could not reach, a row of stitch cores finished the opening.

Lessons learned on this job

Every job teaches the crew something. These are the ones we took from Cremorne, and we use them on every on call coring job.

What worked

• Scan before you core. Marking the cables and bars first on the post tensioned slabs meant the cores went in clear of them
• Mark the size on the concrete. Writing the opening size on the slab before cutting meant everyone agreed on it before a cut was made
• Cut slabs into liftable pieces. A grid of cuts made removing slab areas quick and safe
• The same faces on the job. Keeping a small group of crew on the site meant each visit started quickly, because they knew the building

What was difficult

• Access first. Scaffold sometimes had to be adjusted before holes could be drilled, which costs time on the day
• Horizontal cores in tight spots. Setting up a core rig on a wall from scaffold or in a corner takes more set up than a floor core
• Short visits. Lots of small jobs across many days means planning each visit so the crew brings the right barrels and saws
• Services not always marked. On some days the services near the work had not been identified, so the crew had to check before starting

If you have something similar

Builders need a coring and cutting crew they can call in as each area of a building is ready. Have a look at our concrete core drilling Sydney, concrete cutting Sydney and concrete scanning Sydney pages, or get in touch.