Concrete is one of the most widely used building materials in construction. It is strong, durable, and can be cast into any shape. However, concrete is also quite brittle and can be difficult to cut or modify once it has cured. Cutting concrete is often necessary during construction or renovation projects when openings need to be made for things like windows, doors, plumbing, or electrical conduits. Small projects may require only a few cuts, while large slabs will need extensive cutting to size and shape.
There are several methods for cutting concrete, depending on the application. Hand tools like chisels and jackhammers can be used for small jobs. Masonry saws that use diamond blades are ideal for most applications. And for very thick slabs and foundations, powerful demolition equipment may be required. When choosing a cutting method, it is important to consider the size and depth of the cuts, the required precision, and any access or safety issues.
One of the most common questions is whether a standard circular saw with an abrasive concrete cutting blade can be used to cut concrete. In comparison to expensive specialty concrete saws, circular saws are an affordable and available option in most home workshops. But can they make the tough cuts through concrete that are often needed?
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What is concrete made of?
To understand if a circular saw is appropriate for cutting concrete, you need to understand exactly what concrete is and why it is so difficult to cut. Concrete is a composite material made by mixing together a binder, aggregates, and water.
The binder acts like glue and holds the mixture together. Portland cement is the most common binding agent. It starts out as a dry powder but undergoes a chemical reaction called hydration when water is added. This produces a paste that hardens and gains strength over time.
The aggregates in concrete give it its bulk, dimensional stability, and impact resistance. Aggregates can be fine materials like sand or coarse gravel, crushed stone, or recycled concrete pieces. The size and grading of the aggregates influence the ultimate strength and finish of the concrete.
Water allows the cement to undergo its hydration reaction and provides workability so that the concrete can be poured and finished. The water content is carefully controlled to get adequate hydration without compromising strength through excess water.
Once the ingredients are thoroughly mixed, the concrete can be poured into forms to produce the desired shape – anything from a sidewalk or driveway to walls, countertops, or sculpture. Over its initial curing period, excess water evaporates away, allowing hydration to continue and unhydrated cement particles to link together and gain strength.
Why is concrete difficult to cut?
Concrete’s strength comes from the interlocking crystalline structure formed by cement hydration. Although concrete begins curing as soon as it is poured, full curing can take up to 28 days. The concrete keeps getting harder and denser over time, making it more difficult to penetrate and cut.
Several factors contribute to concrete’s resistance to cutting:
- Hard aggregates – Sand grains, gravel, and crushed stone are much harder than the cement paste binding them together. Trying to saw through these hard bits causes extreme abrasion.
- High compressive strength – Fully cured concrete can have compressive strengths upwards of 5000 psi. The dense crystalline structure requires high pressure from cutting tools.
- Brittleness – Unlike wood which has some give, concrete has low tensile strength. Attempts to cut or bend concrete will cause cracks and crumbling.
The cement paste alone can actually be cut relatively easily in its hydrated state. But the aggregates make up over 60% of a typical concrete mix and present the real challenge to cutting and drilling concrete.
Can You Use a Circular Saw to Cut Concrete?
Concrete cutting circular saws are specially designed for abrasive cutting through concrete:
- Powerful high-torque motor – Generating the forces necessary for concrete cutting requires 15 amps or more motor power.
- Diamond or abrasive blade – Standard wood or metal blades will almost instantly fail. Concrete circular saws use industrial diamond or carbide grit blades.
- WUFC arbor – A unique arbor design called WUFC (wet utility saw flush cut) allows cutting directly up against walls and floor.
- Water cooling – Water prevents dangerous overheating of the blade and keeps dust levels down.
In contrast, typical 7-1/4” electric circular saws used for wood have lower amperage universal motors designed for fast blade speeds up to 5500 RPM. They lack the torque and mechanical strength for concrete work. Standard safety guards also interfere with flush cutting. And using an abrasive blade dry causes extreme wear from heat buildup.
While it is physically possible to cut concrete with a standard circular saw and a diamond blade, it is not recommended for anything beyond a couple shallow passes:
- Motor burnout – Standard 15 amp motors can’t handle the torque demands of concrete cutting for long.
- Immediate blade wear – Universal arbors allow excessive vibration that can quickly destroy abrasive blades.
- Overheating – Friction builds without water cooling risking dangerous kickback as the blade binds.
- Poor cut quality – Universal motors lack the precision speed control needed for clean cuts.
- Excess dust – Dry cutting creates a dangerous silica dust breathing hazard.
You can improve the capability of a standard circular saw for occasional concrete cutting by:
- Using the highest amperage saw available
- Fitting a diamond grit blade rated for concrete work
- Allowing time between passes for cooling
- Using water spray to keep the blade wet
- Always wearing respiratory protection against silica dust
However, for heavy duty concrete cutting, the right specialized tool for the job is highly recommended for safety, precision, and efficiency.
Types of Concrete Saws
There are several types of saws designed specifically for cutting concrete:
Handheld Concrete Saws
Compact, lightweight handheld saws allow control and mobility for small concrete jobs:
- Cut-off saws – Smaller blades up to 14” diameter for control and tight access.
- Flat saws – Guide rails can be added for precise straight cuts.
- Ring saws – Circular blades designed for plunge cuts in the middle of a slab.
- Chain saws – Use a rotating concrete chain rather than a blade.
Walk-Behind Concrete Saws
Heavier duty saws on guide wheels are ideal for long cuts:
- Flat saws – Straight cuts across floors and slabs with blades up to 20”.
- Ring saws – Make openings or utility cuts with up to 26” diameter blades.
Wall Sawing
Large track-mounted saws use massive diamond-edge blades to penetrate thick slabs and walls:
- Core drilling – Remove cylindrical cores to form openings.
- Flat sawing – Cut deep slots in walls and floors.
- Wire sawing – Use a diamond wire to make accurate cuts with no vibration.
Specialized Saws
Unique concrete saws meet specific needs:
- Floor scrapers – Level high spots and plane concrete surfaces.
- Grooving and jointing saws – Cut control joints.
- Robotic saws – Automated sawing for extreme precision requirements.
Factors When Choosing a Concrete Saw
Consider the following factors when selecting a concrete saw for professional and residential applications:
Cutting Depth
Handheld saws are generally limited to 2” maximum depth. Walk-behind saws can handle up to 6”. Heavy duty wall sawing systems cut up to 36” deep. Know the slab thickness and cutting goals.
Power
Gasoline engines from 5hp to 20hp are common in handheld saws. Walk-behind saws use larger engines or electric motors. Wall systems use 20hp or larger diesel power units. Match power to the cut size.
Water Supply
Concrete saws require adequate water – from bottles on small saws up to 20 gpm on large walk-behinds. Plan water needs based on cut length.
Blade Size
Larger diameter blades cut wider and deeper. But large blades on small saws can lack control and overheat motors. Optimal blade sizing balances capabilities with control.
Accessibility
Assess the cutting location and obstacles. Be sure the saw size allows access without blocking walkways or creating hazards.
Precision
How straight and accurate does the cut need to be? Precision saws like flat saws with guide rails provide the most accuracy.
Portability
Smaller handheld saws can be carried and maneuvered in tight spaces. Roll-around saws tradeoff weight for stability.
Safety
Concrete saws generate large amounts of silica dust. Water suppression and respiratory protection are essential. Proximity sensors and guards protect operators.
Cost
Equipment rental provides access to concrete saws at all sizes. Expect rental fees from $50 per day for walk-behinds up to $1500 per day for wall saws. Handheld saw purchase prices start around $400. Large track systems can cost over $100,000.
| Saw Type | Cutting Depth | Blade Size | Power | Water Needed | Advantages | Disadvantages |
|---|---|---|---|---|---|---|
| Handheld Cutoff Saw | 1-2” | 4-14” | 10-15 amp electric or 5hp gas | Water bottle | – Lightweight and portable – Tight access cutting – Low cost |
– Limited depth – Low water supply – High operator skill needed |
| Walk-Behind Flat Saw | 3-6” | 12-20” | 15hp gasoline or electric | 5-20 gpm | – Long, straight cuts – Good depth – Stable guiding |
– Not highly portable – Limited curved cuts |
| Wall Saw | 6-36” | 16-72” | 20+ hp diesel | 20+ gpm | – Massive depth – Extreme precision – Slot or core cuts |
– High equipment cost – Low portability – Expert operation |
Cutting Concrete with a Circular Saw
While concrete cutting circular saws are ideal for most jobs, occasional light duty cutting can be done with a standard circular saw by following a few guidelines:
Equipment
Use a circular saw with the highest available amperage – never less than 15 amps. The blade should be matched to the saw’s arbor size, either 5/8 or 1 inch. Choose an abrasive concrete cutting blade. Make sure the blade depth matches the intended cutting depth.
Control
Clamp a straightedge guide to the concrete to keep the saw steady and ensure a straight cut. Make several shallow passes rather than trying to cut the full depth in one pass. Let the blade work through the material gradually.
Cooling
Water is essential to cool the blade and control dust. Have a spray bottle or hose ready. Flood the blade during cuts and spray liberally in between passes. The water will quickly slurry the concrete dust.
Safety Gear
Always wear safety glasses and hearing protection when using a concrete saw. A dust mask or respirator is critical to avoid inhaling hazardous silica dust particles. Water suppression helps reduce dust. Consider a face shield for additional facial protection.
Cleanup
Concrete slurry accumulating in the cut area can bind the blade. Flush the cut frequently with fresh water to keep the area clean. Check the circular saw for buildup occasionally and clean as needed.
Maintenance
Inspect the blade after cutting for wear and damage. Expect to replace the blade after using it for concrete. Check that the saw arbor is still tight and running true. Lubricate and clean the saw to prevent concrete slurry buildup in the motor.
Conclusion
While it is possible to use a standard circular saw for occasional, light-duty concrete cutting, the rigors of abrasive concrete materials make specialized concrete saws far superior for frequent or heavy sawing jobs. If you choose to cut concrete with a typical circular saw, take precautions like using a high quality diamond blade, maintaining water cooling of the blade, and equipping proper safety protection against silica dust hazards. However, investing in the proper concrete cutting tool designed for the purpose will provide faster, deeper, more precise, and safer concrete cutting. With the right saw, you can cut concrete cleanly, efficiently and expand your construction capabilities.