Concrete Saw Cutting: Wet or Dry?

If using concrete saws is one of the daily tasks for your company, this decision is an important one. How you cut will have an impact on employee health as well as project quality, and the aesthetics of the materials you’re cutting. I’ll present the pros and cons of each cutting method as I see them, and you can decide which is right for you.

Wet Cutting

Most concrete saws, handheld or otherwise, come stock with a water option. Tub saws include a water pump, handhelds include the plumbing for a household hose connection. And wet cutting has benefits: reduced concrete dust can mean a healthier environment for you and your employees, and less to clean on the structures around you, where airborne dust would normally settle. Diamond blades that run wet also tend to last longer because they stay cooler (even blades designed to run dry can be run wet, and you’ll see a reduction in wear rate). You also won't have to change the air filters on your concrete saw as often, because the water will keep more of the dust from reaching the air intake.

Wetted concrete dust stuck to the walls when we ran our saws with water.

However, I’ve found that wet cutting can also be very messy. With water flow on a handheld concrete saw adjusted too high, you can end up spraying concrete dust-impregnated water all over your jobsite, creating a much more difficult cleaning job later. Even at lower water flow you can still end up having to take scrub brushes and pressure washers to clean nearby structures that have been coated (and I tell you this from personal experience - the photo above is a project where we spent the better part of a day pressure washing and scrubbing the walls of part the client's home to get the wetted concrete dust off). With that also comes dumping lots of lubricated dust over the pores of the brick you may be cutting. The water really helps this dust settle deep into the brick, making it nearly impossible to remove (I say “nearly impossible”; someone might be able to do it, but I haven’t figured out how). The result is cut brick that are two shades lighter than uncut brick, and the result of that is usually a long discussion with the client.

Dry Cutting

Dry cutting seems to be less popular in recent years. At a recent jobsite we even had a neighbor call the local health department, claiming we were creating too much dust. The guy from the health department was much more reasonable than the client’s neighbor, but we did end up having to cut wet. Dry cutting can also be messy, dispersing dust far and wide, covering people and structures. However, I’ve found that a few seconds with a leaf blower solves that issue. Dry cutting also presents a hazard for your employees; sucking concrete saw dust into their lungs for years is sure to cause problems down the road.

Without a respirator, the dust from a concrete saw run dry would make it hard to breathe.

However, cutting dry preserves the look of the material you’re cutting. Most all of the dust is sent into the air, leaving only a small bit of dust on the cut material, which again can be cleaned quickly and effectively with a leaf blower. To address the employee hazard, we like to use safety gear that includes eye and hearing protection, but more important for long-term health issues, we use respirators. A simple half-mask respirator with dual filters provide good airflow and a tight seal around the mouth and face, preventing ‘blow by’ of dust around the sides of the mask (this will happen with the cheap paper dust masks you can find at hardware stores). It keeps the lungs of my employees pink, and allows us to provide our clients with a better finished project.


DIAMOND BLADE SELECTION AND USE
The Evolution of the Diamond Blade
Cleaning a Paver Saw Blade
Concrete Saw Decision - to Cut Wet or Dry
Blade Choices - Which is the Best for your Masonry Saw
Mounting a Used Diamond Blade