Cut Concrete
It's possible to cut concrete to differing specifications than normal. Any concrete deeper than 4 inches (101.6 mm) is well within the range of your capabilities, but increasing depth adds to the difficulty of the work. This article explains how to cut concrete for sidewalks, patios, basement walls and house slabs that are not normally deeper than 6 inches (152.4 mm). Cutting concrete deeper than 6 inches (152.4 mm) should be performed by a professional with equipment that can handle deeper concrete.
It is vital to wear appropriate protective gear of adequate robustness at all times when sawing concrete. See warnings section below.
Steps
- Lay out the area of concrete to be cut.
- You need to use a chalk line and box to mark a straight line on the concrete. This is the area to be cut.
- Use a 15-amp circular saw with a diamond or abrasive blade to cut a depth of 2 inches (50.8 mm). This works particularly well when working with a sidewalk.
- Set the blade depth of your circular saw at 2 inches (50.8 mm).
- Begin cutting at the edge of the concrete and slowly follow the line you have laid out with your chalk line. I have found keeping the blade wet by pouring water on it as you cut reduces dust and helps keep the blade cooler.
- This depth of cut will give you a straight edge scoring the concrete to finish breaking the remaining depth and a straight edge at the top to tie in with fresh concrete.
- Employ a gasoline or electric powered cut-off saw to get the job done when working with concrete deeper than 4 inches (101.6 mm).
- The cut-off saw allows you to penetrate to a depth of 6 inches (152.4 mm).
- Most driveways, housing slabs and basement or concrete retainer walls are in this range.
- Follow the same steps as you did in the use of a circular saw and identify your starting point.
- Cut concrete to the correct depth.
- Proceed slowly, maintaining minimum RPMs of the cut-off saw. Slow speed allows the saw to keep from overheating the blade and causing shrapnel-like pieces to be tossed into the air from a broken blade.
- If you have helpers, have them keep the chalk line free of concrete dust made by the saw cut.
Tips
- This technique is perfect for cutting or scoring concrete for decorative purposes. In addition, you will be able to allow standing water to drain from the concrete more easily.
- You really need two people for this job -- yourself and someone who does not mind getting dirty.
- When working with a gasoline-powered saw, extend the life of the blade by dripping water on the cutting edge as you work. A garden hose that is set very low and only dribbles onto your blade keeps down the dust and keeps the blade cooler.
- If you do not own a cut-off saw, you can buy or rent one from a home improvement store.
Warnings
- When using a cut-off saw, always wear protective gear. Steel-toed shoes, shin guards, goggles, a full face shield and hard hat to protect yourself and heavy duty gloves. Because cement dust is harmful if inhaled, an efficient and close fitting dust mask (respirator) is required. Protect your hearing and sight with cup-type ear defenders and goggles. Knee pads will markedly increase your comfort when kneeling. Not only will taking these protective steps preserve your health and senses, they will also make the job very much less unpleasant and reduce fatigue.
- Do not use water on or near an electric saw.
- Wash off accumulated dust from your body as soon as the job is done.
- Abrasive blades are less expensive than diamond-coated blades, but will wear out much quicker.
Things You'll Need
- 15 amp gas or electric circular saw, 6-7 inch (152.4-177.8 mm)
- Diamond or abrasive circular saw blade
- Chalk line and box
- High filtration, close fitting dust mask
- Eye protection
- Ear defenders
- Steel-toed shoes
- Broom
- Full face shield
- Shin guards
- Water hose and available water facet if using gasoline-powered saw
Related Articles
- Cut Cement
- Bend and Cut Rebar
- Break Up Concrete
- Finish Concrete
