Basic Repair of Concrete Trip Hazards, Gaps and Cracks

It’s finally summer and the ice has melted, the sun is shining and you see sidewalks and concrete slabs everywhere that have formed fissures and elevated cracks because of ground shifting and moisture from a long wet winter.

These trip hazards need to be fixed and a restoration contractor with a little ‘know how’ can make a tidy sum of money while making the world a little bit safer one concrete slab at a time.

Here is a typical example of a concrete fissure formed by ground shifts and moisture.

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To a healthy, able bodied person this fracture with a 3″ lip may not seem like such a big deal, but to the elderly and mothers with small children this is a dangerous hazard.

You don’t need to be a large concrete grinding operation to tackle jobs like this. Cracks and fissures of this nature form all the time in the driveways of your existing clients, the sidewalks of your commercial accounts and everywhere in your neighborhood where you live.

This blog will show you the steps you need to take in order to effectively fix these hazards while making money doing it.

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A ‘scarifier’ is aptly named. When you first try using one the experience is pretty scary. (ok, enough jokes) …but seriously, it’s insanely scary when you fire one up for the first time. This size scarifier is considered a ‘mini’. They are available much, much larger.

You might own a weighted 17″ side by side or a large concrete grinder (either planetary or counter rotating) but the most ideal machine for tackling this problem effectively is a scarifier.

One side of the lip of the fissure is raised 3″, so using a weighted side by side and trying to hold it onto one side of the fissure in order to grind down is not only uncomfortable, but ugly. Another good reason not to use a weighted side by side machine when there is an elevation differential is that you will more likely be effecting a larger area, but with a scarifier you can focus on just the crack as opposed to making a 4′ wide swing with a side by side machine. Why expend energy where the crack isn’t. By focusing on the area you can be more efficient and profitable.


Looks like the surface of Mars…

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That’s why scarifiers are handy if you know how to use them…

After you’ve gotten both sides the concrete fissure leveled we can begin to smooth out the damage done by the scarifier with a metallic grinding disk.

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You could get on your hands and knees to grind, or you can get a stand-up model which will make the job much more pleasant…and save your knees.


Using a metal disk to grind will smooth out the concrete and make for a visually attractive repair. If you leave behind scarifier scars then they’ll know you’re a rookie or worse yet, lazy. 🙂

This ugly leveling job was done right in front of the home of Josh Jones, the President of STI Prepmaster and an industry concrete expert. He naturally wanted to jack hammer it out but I told him that the art world might have better appreciation for it…


This may be the work of a great artist…or a very lazy city worker…bleah.



With the help of his fake dog Ariel, or Argentina or whatever he calls it, Josh used a scarifier to properly level and then he used a grinder to properly grind. He’s sending the bill to his local councilman.


Now let’s get rid of those nasty scars from the scarifier… (scars, scarifier… you see what I did there?) 🙂

You can see that we are using vacuums to keep from making a cloud of silica dust. New laws have been passed requiring a proper vacuum to be hooked up to any silica dust creating machinery. The days of using a plain weighted machine with no dust shroud are gone to dry grind are gone. Making a cloud of silica dust can risk a $5000 fine.


Flat, smooth and vacuumed out, now we are ready to fill the crack with self leveling exterior crack repair caulk.


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Here’s a view from a different angle. We have exposed some of the aggregate in this process, but the idea was to make it smooth and flat to eliminate the trip hazard. The visual architectural appearance was low on the list compared to the safety needs.

Use self leveling caulk to make sure it will get down into the crevices for deep fissures.

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In this case the client overfilled and flattened the caulk in order to make sure it went all the way down. After it becomes tacky, they’ll scrap off the excess…


…or maybe they’ll leave it… They drove over it already. Nice and flat. No more trip hazard.

From a large crack with a 3″ height differential on either side we now have a repair that any property manager could be proud of. This is just a basic job, in some cases you have expansion joints to worry about and other engineering considerations.

This is just to show a basic repair that most restoration professionals can do on a driveway, a sidewalk or in this case, a parking lot.

My name is Robert Falzone and I train folks how to solve problems in the industries of cleaning & restoration, abatement and surface prep. If you would like a consult, contact me via the my information found in the ‘About’ section of this blog.

Thank you for your support. Mr. Verdell Barkaroni says, ‘Hi’.