Concrete cutting: cost of cutting per linear metre 2026, core drilling and openings

When concrete is cut, a diamond tool separates exactly the part of the structure you want removed. A demolition hammer works differently: it pounds the wall, and the vibration travels into the floors, ceilings and neighbouring walls. A saw does not shake the building like that, and the edge of the opening stays straight. So cutting is the usual choice wherever the rest of the building stays in use: a new doorway in a concrete wall, a larger window, a hole for ventilation ducts or drainage, or floor alterations in a house that people live in.

Breaking out makes sense when a whole element is coming down and the surroundings can cope with the vibration. In a block of flats built from precast concrete panels, cutting is practically the only way to change the layout without damaging your neighbours' flats. Hammering through a reinforced concrete panel breaks up the concrete that protects the steel around the opening. Plaster in the flats above and below you can then crack.

Ordinary wall openings are cut with a wall saw that runs on a track. The contractor anchors the track to the wall, and the saw travels along it exactly on the marked line, so the edges of the opening come out plumb and straight. A hand-held saw with a smaller blade handles shorter cuts, finishing corners and spots where the track will not fit.

• A wire saw comes in for thick, heavy elements, foundations and anywhere a blade cannot reach deep enough. A diamond wire is threaded through drilled holes and pulled through the concrete under tension.
• A core drill with a diamond core bit drills a round hole and pulls out a complete cylinder of concrete. It is used for service holes, for the corners of openings and, with wire sawing, to make a hole for threading the wire through the wall.
• A concrete chainsaw finishes a square corner without running past it. A circular blade always overshoots a little in the corner, a chain does not.

Concrete cutting tools use synthetic diamonds made under high pressure and temperature. They are not a cheap imitation. Synthetic diamond has the same carbon crystal structure as natural diamond. It is simply made as fine industrial grit rather than as gemstones.

The grit is baked into a metal bond, usually based on cobalt, iron or bronze. This mix is formed into segments, which are welded onto the steel body of the blade or core bit. So the diamond is not spread through the whole blade, only the rim does the cutting. As the tool works, the bond slowly wears away and exposes fresh grit. Concrete with hard aggregate and a lot of steel wears segments down faster. That is why a contractor asks you about the type of concrete and the amount of reinforcement before giving a quote.

If a segment overheats, the diamonds fall out and the segment can even break off. So the blade is cooled with water, or the cut is made with dust extraction and with breaks, as the tool manufacturer recommends.

In panel blocks the ceilings rest on vertical wall panels, usually around 140 to 150 mm thick. Partitions are thinner and carry nothing. At first glance, though, you cannot always tell them apart from a load-bearing wall, especially if the flat has been altered before. A structural engineer therefore looks not only at your flat but also at alterations in the flats above and below. Openings stacked on top of each other affect one another.

If the opening goes into a load-bearing wall, the order of work is what matters:

1. Prop the ceiling with temporary props on both sides of the wall before the first cut.
2. Cut the opening and remove it in sections.
3. Install a permanent steel frame or lintel to the structural design, usually welded from steel sections and grouted or anchored in place.
4. Remove the props only once the permanent structure has taken the load.

For smaller openings in brick or block walls, clay or concrete lintels can sometimes replace a steel frame. The type and size of support always comes from the structural calculation. The experience of the cutting contractor is no substitute for it.

Precast panel or cast-in-place wall

A precast panel and a cast-in-place wall of the same thickness are cut in much the same way. The main difference is how much steel they contain and where it sits. Panels have reinforcement concentrated around the original openings and at the joints, while cast-in-place walls tend to have it across the whole area near both faces. What counts is the real wall thickness and the density of steel, which a scan will show. When you pick an item in the price list, go by the thickness of the element, not by what the owner calls the wall.

A structural report is a technical document, not a permit. In a block of flats, the load-bearing walls are usually common parts of the building, so you need the consent of the other owners before touching them. How the vote works and what majority is needed depends on the type of decision and on the rules of your building. Check it with the building management or the owners' association.

Work on the load-bearing structure is normally not one of the minor jobs you can do without any formal procedure. Whether a simple notification is enough or a building permit is required depends on local building regulations, on the scope of the work and on the documents you submit. Do not assume a notification will do. Ask the local building authority before you order the cutting. In practice both the authority and the building management want to see a structural report, so it pays to commission that as the very first step.

Even where no load-bearing wall is involved, the house rules of the building still apply. Keep noisy work to the permitted hours and let your neighbours know in advance what to expect.

Concrete contains quartz sand. Cutting it dry produces very fine respirable crystalline silica dust, which gets deep into the lungs. Health and safety rules in many countries treat this dust as a serious hazard, and in the EU work that generates it is classed as a process with a carcinogenic effect. So water or extraction is there mainly to protect people, not just the blade.

Wet cutting indoors has its own problems, though. It produces concrete slurry that stains floors, clogs drains and, if the floor is not watertight, can leak through to the neighbours. Indoors, one of two approaches is usually chosen:

• wet cutting, with the slurry caught in trays under the cut and sucked up with a wet vacuum
• dry cutting, with an H-class industrial extractor connected directly to the blade guard and respirators for the workers

Either way, it is worth covering the floors with plastic sheeting and rigid boards on top, moving the furniture out, closing the doors to other rooms and switching off any circuits that run in the wall. In panel blocks the wiring is often cast straight into the panel, so the cables are traced and disconnected before cutting. Only a qualified electrician may disconnect them and run new wiring.

Take care around service cores and shafts in older blocks too. Boards around the risers may contain asbestos cement. Do not cut or remove that material yourself. It is a job for a licensed asbestos contractor.

Concrete weighs roughly 2,400 kg per cubic metre. The cut-out for a doorway of about 900 × 2,000 mm in a 150 mm wall therefore weighs around 650 to 750 kg. Nobody can safely lift a piece like that out in a flat or carry it down the stairs. So the cut-out is divided by extra cuts into pieces that two people or a small lifting aid can handle, usually around 50 to 100 kg each.

The length of cut is therefore counted from every cut the saw makes, not just the outline of the opening. In practice a doorway often has a perimeter of about 5 to 6 linear metres, while the total length of cut comes closer to double that. When you compare quotes, check whether the contractor has included the dividing cuts.

The second point is corners. A circular blade cannot finish a square corner without the cut from one side running past it. That overcut weakens the wall exactly where the stress is highest. The fix is a core hole at each corner, with straight cuts made between the holes, or finishing the corners with a chainsaw. For a rectangular opening that means four core holes, not one.

In new brick or block walls, chases for cables and water pipes are cut with a twin-blade wall chaser connected to an extractor. Load-bearing concrete panels are usually not chased at all, or only as far as the structural engineer allows. A deep horizontal chase can sever the reinforcement and weaken the wall along its whole length. In panel blocks new services are therefore usually run in a lining wall, in trunking or in the floor.

When you do cut chases, keep to the usual installation zones: horizontal runs just below the ceiling and just above the floor, vertical runs next to corners and openings. Anyone who drills into the wall later will then know where to expect cables and pipes.

Typical holes through a panel are for a cooker hood, bathroom ventilation, condensate drainage from air conditioning or a new drainage branch. The core hole should slope slightly towards the outside so that water does not run in. Once the pipe is in, the gap is sealed to suit the type of penetration. Where it passes through a fire-separating wall or floor, certified fire-stopping is used.

Cut concrete counts as construction waste, not household waste, and it is usually not hazardous. Clean concrete without other materials mixed in is accepted by recycling yards and crushing plants. Keep the waste transfer note or receipt from the licensed waste handler, because the building management or the building authority may ask for it. Material containing asbestos is a different matter: it is hazardous waste and follows its own rules.

Do not store heavy pieces on a balcony or in a single pile on the floor. They put unnecessary load on the slab.

You can manage a small round hole yourself, for example for a cable or a thin pipe, through a non-load-bearing brick partition or through plaster. Do not drill into a concrete panel, a load-bearing wall, a ceiling slab or the external wall of a block of flats yourself. That is work for a specialist core drilling contractor, and only after a structural engineer has assessed it.

1. Confirm that the wall is a non-load-bearing partition made of brick or blocks, not concrete. If you are not sure, stop and call in a professional.
2. Scan around the planned hole with a cable and pipe detector and keep away from the installation zones near corners, above the floor and below the ceiling.
3. Switch off the circuit breaker for the circuit in the partition and check at a socket or switch that it is dead.
4. Cover the floor, connect a vacuum with a fine filter to the drill and put on an FFP2 or FFP3 respirator, safety glasses and hearing protection.
5. Mark the centre of the hole on both sides of the partition, drill right through with the pilot bit and only then fit the core bit.
6. Drill with the core bit at low speed with the hammer action off, halfway from one side and the rest from the other, so the plaster does not break away.
7. Remove the core, vacuum the dust from the hole and the surrounding area and fit a protective sleeve or grommet.
8. Switch the breaker back on and check that the circuit works. If you hit metal or felt unusual resistance while drilling, leave the hole unfinished and call an electrician or a plumber.

• You had the structural report and the owners' consent in hand before cutting started
• The props supported the ceiling throughout the cutting and were removed only after the permanent structure was in place
• The size and position of the opening match the design and the edges are plumb
• There are no overcuts past the line of the opening in the corners
• The steel frame or lintel is installed to the structural design and its bearings are grouted
• No new cracks have appeared in the wall or in the ceiling above the opening
• Any interrupted services have been properly disconnected or rerouted and you have the paperwork for it
• Service holes slope towards the outside and the gap around each pipe is sealed
• Floors, drains and neighbouring rooms are clean and free of slurry
• You received the waste transfer note together with the handover of the work