Key takeaways
- Respirable crystalline silica comes from common residential processes including cutting masonry, grinding mortar and mixing dry bagged products, not only from engineered stone.
- On-tool water or dust extraction is the primary control for cutting and grinding, and the shroud, blade and hose set-up matters more than the badge on the tool.
- Mixing is the most under-controlled silica task on residential sites because the dust is released at chest height with no obvious cutting action to prompt controls.
- Dry sweeping and compressed air move settled silica back into the breathing zone, so housekeeping method is a control measure, not a clean-up afterthought.
- Respiratory protection is the last line of defence behind engineering controls and should not be the only control on a task that can be wet cut or extracted.
Respirable crystalline silica is the fine fraction of dust that reaches the deep part of the lung, and on a residential site it is generated by ordinary tasks: cutting masonry, grinding mortar, chasing brickwork, mixing bagged products and sweeping up afterwards. The dust is not visible in the way sawdust is visible, and the tasks that produce it are often treated as small jobs that do not need a control plan.
The engineered stone ban has changed what happens in benchtop fabrication, but it has not changed the rest of the site. A builder cutting Hebel, a tiler grinding a bedding coat, a renderer mixing a bag of base coat and a labourer sweeping a slab all produce the same hazard, and the controls for those tasks are the responsibility of the principal contractor and the person doing the work.
This article is about control measures and tool set-up. It does not repeat the engineered stone rules, which are covered elsewhere; it deals with the cutting, grinding and mixing that happens on nearly every residential job in NSW.
What actually generates respirable silica on a residential site
Silica is a mineral found in sand, stone, concrete, brick, tile, mortar and many bagged products. When those materials are cut, ground, drilled or mixed, the fine fraction becomes airborne and stays airborne long enough to be inhaled. The hazard is not the total amount of dust on the site; it is the fraction small enough to reach the lung, and that fraction is produced in greater quantities by high-energy processes such as dry cutting with a disc.
The practical implication is that the risk follows the process, not the material list. A small amount of the wrong material cut dry can produce more respirable dust than a large amount of material cut wet. This is why the control plan has to be built around what the tool is doing, how fast it is doing it, and whether the dust is being suppressed or captured at the point of generation.
It also means that a builder cannot rely on a material safety data sheet alone to decide the controls. The data sheet tells you the product contains crystalline silica; it does not tell you how much dust your blade will make when you cut it dry on a windy slab. That judgement comes from the task, the tool and the environment.
On-tool controls: water and extraction
The most effective control for cutting and grinding is to stop the dust becoming airborne in the first place. On-tool water and on-tool extraction are the two standard methods, and both work only when the tool is set up correctly.
For wet cutting, the water has to reach the blade at the point of contact and at a flow rate that keeps the cut wet, not just damp. A trickle that evaporates before the blade finishes the cut is not a control. Slurry is the by-product and it has to be managed, because once it dries the fine fraction can be disturbed again by foot traffic, wind or clean-up.
For extraction, the shroud has to match the blade diameter and the depth of cut. A shroud that is too large for the blade will not capture dust at the source, and one that is too small will not fit over the guard. The hose has to be the right diameter for the extractor and free of splits or blockages, because a vacuum reading at the unit does not tell you what is happening at the shroud. The extractor must be suitable for the material and maintained, including filter changes, which are themselves a dust-generating task if done without care.
Neither method removes the need for the operator to think about position. Standing directly in the plume, or cutting with the wind at your back, puts the dust into your breathing zone regardless of how good the tool is.
Lead in. The mistake that costs the most is buying an extraction unit and then running the wrong shroud or a blocked hose, because the job looks controlled while the dust is going straight past the operator. The cost shows up years later as a compensable disease, and the paper trail will show what was on site.
Choosing the right tool and blade for the task
Tool selection is a silica control. A smaller blade, a slower feed rate and a sharper blade all reduce the amount of fine dust produced for the same cut. A blunt blade rubs rather than cuts, and rubbing generates more fines. A blade rated for the material cuts more efficiently and produces less dust than one that is being pushed through a material it was not designed for.
Battery tools have made cutting more portable, which is convenient but can also mean more dry cutting in locations where water is difficult to run. If the task cannot be wet cut and cannot be extracted effectively, that is a signal to reconsider the method rather than to rely on a mask.
The same logic applies to grinding and chasing. A grinder with a diamond cup wheel on mortar produces a significant plume, and the shroud and extraction set-up need to be chosen for that specific task. Chasing a wall for services is a high-dust operation that is often done in an occupied or partly finished area, which raises the stakes on containment and clean-up.
For a broader look at how task risk is assessed and documented on residential jobs, see the guide to SWMS templates for residential builders in NSW.
Mixing: the under-controlled task
Mixing dry bagged products releases silica at chest height, often in a confined area, and it is frequently done without any control beyond a mask. The dust comes off the top of the bag as it is opened, off the pour as it goes into the mixer, and off the mixer as it turns. It is a different mechanism from cutting, and it needs a different set-up.
The controls are straightforward: open bags with the bag low and the opening away from the face, add water before the powder where the product allows, use a mixer with a lid or a shroud where available, and mix in a ventilated area rather than a closed garage. Where the product is particularly dusty, pre-mixed or wet products remove the hazard at the source.
Clean-up after mixing is part of the task. Dry powder on the floor, on ledges and on the outside of the mixer will be disturbed again by the next trade through the area. Wet wiping and vacuuming with the appropriate filtration are the methods that keep it out of the air.
The other under-controlled mixing task is the use of a mortar or render mixer in the open. Wind direction matters here; if the mixer is upwind of the work area, the dust is being carried to the people who are not wearing protection.
Ventilation, containment and the limits of each
Ventilation and containment are supporting controls, not substitutes for on-tool controls. Opening a roller door improves general air movement, but it does not capture dust at the blade. Sheeting off an area stops dust migrating to the rest of the house, but it does not protect the person inside the sheeted area.
The two work together. Containment keeps dust out of finished areas and away from other trades, and general ventilation reduces the concentration in the work area. Where the work is indoors and the dust cannot be captured at the tool, mechanical ventilation or a filtered air mover can help, provided the air is filtered and not simply blown from one part of the room to another.
Containment also has to survive the job. Sheeting that is taped and then walked through loses its seal within a day. Negative pressure units and air scrubbers need power, filters and maintenance, and if they are not checked, they become decoration. The person setting up the containment should be the person who understands what it is meant to achieve.
Electrical safety needs attention wherever water and power are used together, particularly for wet cutting on a slab or in a wet area. The general principles are set out in the Safe Work Australia guidance on electrical safety, and the site set-up should follow them: residual current protection, leads inspected and off the ground where practicable, and tools suitable for the environment.
Respiratory protection and fit
Respiratory protection sits behind the engineering controls. It is the control of last resort, not the first, and it should only be relied on where the dust cannot be controlled at the source, or as a short-term measure while the primary control is being set up.
Where it is used, the protection has to be suitable for the task and fit the person wearing it. A disposable P2 mask that has been in a toolbox for a month, worn over a beard or taken off and put back on with dusty hands, is not providing the protection it appears to provide. Fit checking and, where required, fit testing are part of making the control real.
The other practical issue is that a mask makes the work harder. If the mask is uncomfortable, workers will lift it or remove it for the task that generates the most dust. That is a reason to fix the engineering control rather than to keep pushing respiratory protection as the answer.
Housekeeping and clean-up
Settled dust is a reservoir. Every time it is disturbed, it re-enters the air, and the fine fraction stays there long enough to be inhaled. Dry sweeping and compressed air are the two methods most likely to put it back into the breathing zone, and both are common on residential sites because they are quick.
Wet methods, or a vacuum with the appropriate filtration, are the controls for clean-up. This applies to floors, but also to ledges, window frames, service penetrations and the outside of tools. Dust on the top of a door frame will fall into the room the next time the door is moved.
Waste and slurry need to be contained before they dry. A slurry puddle left to set on a slab will be broken up by the next trade and become airborne again. Bagging, sealing and removing waste promptly is part of the control plan, not a housekeeping preference.
Clothing is another reservoir. Dust on clothing is released when the wearer moves, and it travels home with them. Changing or vacuuming work clothing before leaving the area, and not brushing it down in the driveway, reduces the spread beyond the site.
Housekeeping and containment checks
- Sweeping is replaced with wet methods or a vacuum fitted with the appropriate filtration.
- Compressed air is not used to blow dust off surfaces, tools or clothing.
- Cutting and grinding are kept out of open areas where practicable, and screens or sheeting are used where they are not.
- Dust settles on ledges, frames and services, so those surfaces are included in the clean, not just the floor.
- Waste and slurry are bagged or contained before they dry out and become airborne again.
- Clothing is changed or vacuumed before leaving the area, not brushed down in the driveway.
- The controls are checked again after any change to the tool, the material or the work area.
Supervision, training and what the regulator expects
The principal contractor has to manage the risks of the work, and that includes the risks created by the trades they engage. For silica, this means the controls have to be visible and checkable: a tool with a shroud and a functioning extractor, a water feed that reaches the blade, a mixing area with ventilation, and clean-up that does not put dust back in the air.
Training has to be specific to the task. A general site induction that mentions silica does not tell a worker how to set up a grinder with a cup wheel or how to change a filter without releasing dust. Toolbox talks are a reasonable place to cover the specific set-up for the week’s tasks, particularly when a new process or material is introduced.
Documentation should describe the controls that are actually used. A SWMS that lists respiratory protection as the primary control for a task that can be wet cut is a red flag, because it tells the reader that the hierarchy of control has not been applied. The document should match the job.
Where the work is high risk and requires a specific licence or notification, the requirements are separate from silica controls and are covered in the article on working alone on site.
Worked example: a builder in western Sydney
A builder in western Sydney is renovating a brick veneer home. The scope includes cutting a new opening in a brick wall, grinding a mortar bed for a tiled floor, and mixing bagged render for an external patch. The site is occupied at the front and the family is living in two rooms while the work proceeds.
The first run at the job uses a disc cutter on the brick with no water and no extraction, because the cut is short and the operator is working outside. The grinding is done with a cup wheel and no shroud, and the mixing is done near the garage door with the bag opened at chest height. The clean-up is a dry sweep at the end of each day.
The dust from the brick cut travels into the occupied area through an open window. The family complains, and the builder has to stop work, clean the rooms and reseal them. The grinding leaves a visible haze in the room being tiled, and the tiler refuses to work in it. The dry sweep at the end of the day moves the settled dust from the floor back into the air, where it settles again on the freshly cleaned surfaces.
The reworked approach starts with the method. The brick cut is done with a wet saw, with the water feed checked before the cut and the slurry contained and removed the same day. The grinding is done with a shroud and an extractor matched to the grinder, with the hose checked for splits and the filter changed in a controlled way. The mixing is moved outside, away from the openings, with the bag opened low and the powder added to water.
Clean-up changes to wet wiping and vacuuming with the appropriate filtration, including the ledges and window frames. The containment is checked at the end of each day rather than assumed. The job takes slightly longer on the first day while the set-up is established, and considerably less time than the rework that followed the first attempt.
The lesson is not that the builder did not know about silica. It is that the controls were not set up at the tool, and the cost appeared as rework, complaints and lost time before it appeared as anything else.
Setting up a cutting or grinding tool for silica control
- 1Match the blade or disc to the toolUse the blade or disc rated for the tool and the material, because an incorrect combination increases both dust and kickback risk.
- 2Fit the correct shroudThe shroud must suit the blade diameter and the cut depth, or the extraction will pull from the wrong place.
- 3Connect to water or extractionDecide before the cut starts whether the tool runs wet or on-tool extraction, and set the flow or vacuum to suit.
- 4Check the hose and connectionsA split hose or loose fitting is a common reason a good tool performs badly, so check it before the tool goes up the stairs.
- 5Run the tool before cuttingStart the tool away from the cut and confirm water or airflow is present at the shroud before the blade touches the material.
Common mistakes and how they surface
The first mistake is treating silica as a benchtop problem. The engineered stone ban is well known, and the controls for it are established, but the same hazard exists in brick, tile, concrete and bagged products. A site that controls benchtop cutting and dry sweeps the rest of the house has not controlled the risk.
The second is relying on respiratory protection as the primary control. It is the least reliable control because it depends on fit, maintenance and wearer behaviour, and it fails silently. The failure surfaces years later.
The third is containment that is not maintained. Sheeting that is not sealed, extractors that are not serviced, and water feeds that are not checked all look like controls while doing nothing. The check has to be part of the daily routine.
The fourth is clean-up that redistributes the hazard. Dry sweeping and compressed air are the two fastest ways to put settled dust back into the air, and both are common because they are quick. Wet methods and appropriate vacuuming take longer and are the control.
For related guidance on managing risk in residential work, including the assessment and documentation side, see the article on excavation and trench safety on residential sites.
Wet cutting compared with on-tool extraction
| Wet cutting | On-tool extraction |
|---|---|
| Water suppresses dust at the blade, which suits masonry and concrete cutting. | Extraction captures dust at the shroud, which suits grinding and cutting where water is impractical. |
| Slurry has to be managed so it does not dry and re-release dust. | Filters and collection bags have to be emptied and changed without releasing the contents. |
| Electrical safety needs attention because water and power are in the same area. | The extractor must be matched to the tool and the material for it to work properly. |
| It often suits outdoor cutting and larger blades. | It often suits indoor work and finer finishing tasks. |
| Both methods still require the operator to avoid breathing the plume close to the cut. | Both methods still require housekeeping and, in some cases, respiratory protection. |
What to put in the site routine
The controls only work if they are part of the daily routine. A short pre-start check of the cutting and grinding tools, the water or extraction set-up, the containment and the clean-up method takes less time than the rework that follows a failure. The check should be recorded in a way that suits the size of the job, from a note in the site diary to a checklist attached to the SWMS.
Tool maintenance is part of the routine. Filters, hoses, shrouds and water feeds need to be checked and replaced on a schedule, and the person doing the maintenance needs to know that changing a filter can release dust if it is done carelessly. Spare filters and hoses on site reduce the temptation to keep working with a control that has failed.
Training should be refreshed when the tool, the material or the method changes. A worker who has only ever wet cut masonry needs instruction before running a grinder with a shroud and extractor, and a worker who has only ever mixed in a covered mixer needs instruction before mixing in the open.
Where this fits in the broader safety system
Silica control is one part of the risk management system on a residential site, and it connects to the others. The SWMS for a task should describe the silica controls alongside the other hazards, the induction should cover the site rules for cutting, grinding and mixing, and the supervision should check that the controls are in place and working.
For builders working through their continuing professional development, the safety category is a reasonable place to extend this knowledge, and the guide to how NSW builder CPD works explains how the categories and hours fit together. The PointCPD course catalogue lists the current options, and the PointCPD home page is the starting point for NSW builder CPD courses.
The practical takeaway is that silica is controlled at the tool and at the mix, by people who have been trained to set the control up and check it. The paperwork records what was done; it does not replace it.
Questions builders ask
Do I need to control silica dust when cutting bricks and tiles, or is it only a problem with engineered stone?
Silica is present in brick, tile, concrete, mortar and many bagged products, so cutting and grinding those materials produces respirable crystalline silica. The engineered stone rules are a separate and stricter regime, but they do not replace the general duty to control dust from other silica-containing materials. The control approach is the same: suppress or capture the dust at the tool, and manage clean-up.
Is a mask enough if I am only cutting for a few minutes?
Respiratory protection is the last line of defence and depends on fit, maintenance and wearer behaviour. A short dry cut can produce a high concentration of fine dust, and a mask that is not fit checked or is worn incorrectly will not provide the protection it appears to. Wet cutting or on-tool extraction should be the primary control, with respiratory protection used only where the dust cannot be controlled at the source.
What is the difference between wet cutting and on-tool extraction?
Wet cutting uses water at the blade to suppress dust, which suits masonry and concrete cutting but produces slurry that has to be contained before it dries. On-tool extraction captures dust at the shroud, which suits grinding and cutting where water is impractical, but it depends on the shroud, hose and filter being matched to the tool and maintained. Both are effective when set up correctly and both fail silently when they are not.
How should I clean up dust without putting it back in the air?
Dry sweeping and compressed air move settled dust back into the breathing zone, so they should be replaced with wet methods or a vacuum fitted with the appropriate filtration. Clean-up should include ledges, frames and service penetrations, not just the floor, because dust on those surfaces will be disturbed later. Waste and slurry should be bagged or contained before they dry and become airborne again.
Does opening a roller door count as ventilation for silica dust?
General ventilation improves air movement and reduces the concentration in the work area, but it does not capture dust at the blade or the mixer. It is a supporting control, not a substitute for on-tool water or extraction. Where work is indoors and dust cannot be captured at the source, containment and filtered mechanical ventilation can help, provided the air is filtered rather than simply moved around the room.
What should I check before a worker uses a grinder with a shroud and extractor?
Check that the shroud matches the blade or disc and the depth of cut, that the hose is the right diameter and free of splits or blockages, and that the extractor is suitable for the material and has a serviceable filter. Run the tool away from the cut and confirm airflow at the shroud before the disc touches the material. The operator should also be positioned so the dust plume is not drawn into their breathing zone, and the clean-up method should be agreed before the task starts.
Sources
- Engineered stone ban · Safe Work Australia
- Asbestos in the home · Asbestos and Silica Safety and Eradication Agency
- Drone rules · Civil Aviation Safety Authority
- Electrical safety · Safe Work Australia
Published 12 July 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.
