Stitch
drilling.

Want the long version? Read the full stitch-drilling guide.

What stitch drilling is

Stitch drilling is a line of overlapping core holes that, taken together, form a cut — think of perforating a sheet of paper to tear it cleanly, in concrete. The crew sets a stand-mounted core rig over the marked-out line, drills the first core, moves the rig the agreed pitch and drills the next, each core overlapping the last by 20 – 40mm. When the line is complete, the stitched section is broken out and the opening is dressed.

It's slower than sawing — the only reason to choose it is when sawing isn't possible. When that's the case, stitching is usually the cleanest, lowest-risk option there is: no percussive impact, no shock to the surrounding structure, and every hole plotted around what the scan found.

When stitch drilling is the right call

• Thick sections — walls and slabs beyond wall-saw depth. Our wall saw cuts to 730mm; past that, stitch drilling from one side is the realistic option for 800mm or 1000mm structural elements.
• Heavily reinforced concrete — door and plant openings in slabs where rebar density rules out other methods.
• Restricted access — plant rooms, basement vaults, listed buildings. Core rigs come apart small and re-assemble in tight spaces where a saw rail won't fit.
• Around live services — every hole plotted to dodge cables, ducts and PT cables. We scan first.
• Curved or shaped openings — saws cut straight lines; a row of stitched cores can follow a curve.
• Vibration-sensitive sites — one of the lowest-vibration ways to cut a structural opening. Occupied buildings, hospitals, listed structures.

Who it helps

Main contractors planning structural alterations on live or occupied buildings. Demolition contractors needing controlled section removal on a sequenced project. M&E contractors cutting plant openings in heavily reinforced or post-tensioned slabs. Refurbishment and heritage teams working on brittle substrates and sensitive finishes where percussive breaking is off the table. If the opening is awkward enough that you're not sure who to call, this is the page — or see specialist works for the wider capability.

What to send for a fast quote

• Drawing or sketch of the opening, with dimensions.
• Slab or wall thickness.
• What's around — services, structure, finished surfaces.
• Reinforcement and post-tension notes if known.
• Access details — floor level, lift availability, working hours.
• Postcode for travel.

Not sure whether stitch drilling is the right method or whether a saw will do? Send the brief and we'll come back with the right approach — and a realistic time on the quote, not an optimistic one. A typical 1m × 1m opening through a 600mm slab runs half to a full crew-day depending on substrate, rebar density and access.

Safety, dust and clean-work notes

Slurry is contained the same way as any wet diamond drilling — vacuumed, captured and bagged out, with the slab handed back clean. Dry with M-class HEPA extraction where wet isn't an option. Scanning is done before the rig is set on any slab where reinforcement, services or post-tension matter, and RAMS, COSHH and permits are issued before the crew mobilises. Break-out of the stitched section is planned with the structural constraints in mind — sometimes lifted, sometimes light percussion on the remaining ligaments only.

Related services

• Specialist works — restricted access, working at height, controlled removal.
• Core drilling — the standard coring service stitch patterns are built from.
• Concrete cutting — wall, floor and wire sawing when a saw can reach.
• Diamond drilling overview — the method, kit and substrate range.
• Emergency & out-of-hours — stitch openings on weekend permits and night shifts.