I recently needed to cut a 10m length of tarmac at the entrance to our drive because it was in the way of laying some new cobble setts. The previous drive must have been laid 2 or 3 inches from the public path and over time, work has been done which meant fresh tarmac had been laid up to the driveway. When I lifted the old driveway to replace, I was left with overhanging tarmac which needed trimming.
Although it was only a small job, the amount of different opinions I had on the best tool to use was amazing. They included:
9inch Angle grinder
Multi tool (no chance!)
Hammer and chisel
Walk behind road saw
The only realistic options for me were the circular saw and the 9inch grinder. I debated for days about the best way to go and in the end, chose the 9inch grinder, which was definitely the right choice. The reason I hesitated slightly was that I thought the circular saw would be safer, but if you get the right blade, wear gloves, mask, eye and ear protection and really take your time, it’ll be fine.
Using the correct disc is important. If you’re cutting quite a lot of tarmac, you’ll find that an incorrect blade will wear down, heat up excessively and then begin to melt more than cut, which will stick to the blade and potentially damage the grinder.
It’s worth investing a little bit more on the blade to get the job done properly and much more easily. I went with this one from Screwfix.
I also didn’t have a 9inch angle grinder and my plan was to find one on Facebook Marketplace but most of them were very old and for an extra £20, I could get a new one from Screwfix. So that’s what I did, I bought the Titan 2000w electric grinder with the intention of selling after use. I’ve since used it for getting rid of concrete fenceposts, chopping a wall topper down to size and re-sizing some granite setts. So I might just keep it after all!
Cutting the tarmac
Mark the line you want to cut with chalk using any straight edge you can find.
Get your protective gear on and get the grinder up to speed. Don’t start until the grinder is at full speed.
Slowly take the grinder to the line and make sure the dust isn’t blowing towards you. If it is, your cutting the wrong way. I did this to begin with and moved the handle over to the other side. You might want to start at the other end if possible.
Do not go too deep on your first pass. This is how discs get snapped. You will be able to feel if you go to deep.
Let the grinder do all of the work. You don’t need to use force when cutting, again this will increase your chances of breaking the disc.
Go slowly and work to your line. The first pass will give you a guide for the rest of the cut so don’t rush it and get it as neat as you can.
Take a break if you need to. I took 3 or 4 breaks just to give my arms a little rest and to assess what I’d done.
I didn’t get any kick back when cutting tarmac but I was always prepared for it. You need to well balanced and stable. If you’re leaning over in a weird position or off balance the grinder could do you some damage. Always be ready for it.