Q&A for How to Cut Concrete

Use an 8- or 14-inch diamond blade with a gas-powered diamond saw to cut concrete. You can also use it to cut brick and granite.

Use a straight edge to mark your corner with a piece of chalk. Check that the straight edge shows you're marking a 90-degree angle.

Any cutting of the concrete would weaken it somewhat, but concrete has high compressive strength. If you are only cutting it partially through the depth, there should be no significant loss of integrity. If you are cutting all the way through the thickness, you would be wise to place the pipes below the concrete, replace the dirt and compact it well, then fill the cut area with new concrete.

No. I recommend you cut 2" deep first using a circular saw and jack hammer the remaining 2". By doing so, you will avoid overheating your circular saw, and freshly poured concrete will adhere better to the sides of the cut-out, since they are automatically scored when you jack hammer the bottom 2" of slab.

You don't, you remove and re-pour one of the slabs to match whichever slab you like most.

With a Jackhammer or a large Circular Saw equipped with a diamond blade. Or, you may find either utility's starting point and run them up into and through the ceiling and walls to the new location.

Cut two parallel grooves about an inch deep (cutting the groove too deep may weaken the concrete), then use an impact hammer with a chisel blade to chisel our the area between the two grooves. It will be challenging to make the bottom of the groove smooth; patience and careful chiseling will be required.

You should be able to remove the fence with a jackhammer, wheelbarrow, shovel, and dumpster. You may even need a circular saw with a metal cutting blade if there's any reinforcement that hasn't rusted away (or doesn't just break apart).

Drill 4 holes about 8 inches from each side in each of the corners and install 1/2 inch eye bolts with fender washers and nuts. Use a front-end loader or some kind of lift to hoist the slab. Be sure to lay cribbing (wood) under the slab when setting it down, and be sure it is flat so that it wont crack under the stress.

The best option is a larger-than-average circular saw with a diamond blade. These can usually be rented. However, you may still need a sledge hammer or jack hammer if the saw doesn't quite make it all of the way through the concrete.

Use a small jackhammer to cut the concrete just inside the 24" circle, removing excess material inside the circle as required. I have done this using a piece of 3/4" plywood with a 24" hole cut as a guide. Kneeling on the plywood while you cut helps keep it in place. The second time that I did this, I used a concrete drill to make holes just inside the 24" circle, spaced as close as possible. Then I used a sledge to knock out the center material, and the hand-held pneumatic hammer to trim the edges.

4” is a lot. If you can demo the entire slab and pour new, that is your best bet, especially if you need to address what’s causing the lifting/sagging. There are methods where heavily expanding “foam” is injected into holes through a slab to raise it. Or old school mud jacking. Both require special equipment. If you are talking about a slab underneath a structure, it’s more complicated.