How to grind a concrete path lifted by tree roots?

Sputnik

Hey Folks, I've got a concrete path that's lifted because of tree roots. Just wondering if there's a cheat/short term fix (ie less expensive) where I could grind down the main bit that's lifted? Doesn't have to be perfect just less of a trip hazard.

Could i maybe use a sledge hammer to knock off some of it then buy or hire a grinder with a diamond thing on it to smooth it down a bit? Or is that just too much height to do that? at it's highest point on the corner there it's about 50mm above the other slab of concrete.

I wouldn't need it to be perfectly 'flat', can still have a bulge, just try and make it less of a trip hazard where the 'cliff face' is. Thoughts?

JacobZ

Hi @Sputnik,

At around 50 mm height difference, grinding alone is generally not a practical or effective solution. Concrete grinders are better suited to taking off a few millimetres, not that amount of lift, and it would be very time consuming and hard on the equipment.

A sledgehammer would likely work but would be extremely difficult to control and the concrete would never break where you want it to, so I would probably veto that idea.

My suggestion is to make a shallow relief cut using an angle grinder with a diamond blade, say 5-10mm deep, on the top and front face of the concrete, then use a https://www.bunnings.com.au/trojan-115m-brick-bolster_p0551210?srsltid=AfmBOorF-zVwWMNyzZh0yaLuApsEHSAlDjLrWgg7hz7yNWs-kJ980FsT with a hammer, striking the bolster with your hammer as you work along the crack. With some patience, after a few passes, the concrete should in theory break along the path of least resistance, which should be the path straight between the two relief cuts.

If you jump on Youtube and look at how a stone mason cuts stones using a bolster, this is essentially what I am proposing.

In doing this, it is important to note that cutting and breaking concrete will create dust that is detrimental to your health if inhaled so a mask is essential. Anytime the concrete can be wet down to reduce the airborne dust, this is also beneficial. Other personal protective equipment such as eye protection, hearing protection, enclosed shoes and long protective clothing is also essential.

Once the concrete has been broken off, you can tidy up with your angle grinder using a concrete grinding disc such as this https://www.bunnings.com.au/full-boar-125mm-double-row-diamond-cup_p0227341 .

After you are happy with things, I'd suggest you apply a coat of a concrete sealer such as this https://www.bunnings.com.au/crommelin-1l-natural-finish-penetrating-sealer-and-water-repellent_p0356894?srsltid=AfmBOoqXIwFfwCwB8NqWa4VHXZvV0CSkdclj0taN6ekeWitf6-7sU0tC to the cut concrete to help protect it from weathering and damage.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob