Crack in concrete help

[Bill Jobe]

I recently bought and installed a garage door opener. During that process the door was damaged while I was trying to level it.
There is a crack about 1/3 of the width in on one end that has caused one side to raise up about 3/4". From there that section that raised up is actually sinking so the other end is lower. Because of that I only need to remove concrete a distance of perhaps 18"
I hired a guy to install the door and need to figure out a way to level that crack in a hurry. He wants to install the door tomorrow. I don't need to do the whole job right away, just enough that he can adjust the door properly.

Any suggestions?
I know there are geniuses amongst you.

[George Bokros]

Help me out. How does a garage door opener install or damage to the door cause you to need to do something with the concrete? Pictures would be helpful.

[John K Jordan]

I'd hold off on installing the door and first get the floor fixed right first.

I also can't understand what has happened and why. Perhaps you could explain better, draw a diagram, and show some photos.

But just imagining from your confusing description: If you have a piece of concrete that has cracked to make it a free chunk and that is tilting, it sounds like what underneath it is not stable. If that is the case, it might be best to cut out a bigger section, fix what's underneath, and re-pour the section. If you are not experienced with this type of work it would be best to hire it out. Two join new concrete with existing, as when patching such a spot as I'm imagining, I like to drill holes in the existing and epoxy rebar into the holes, add sufficient additional rebar, then form up the spot and pour new concrete.

JKJ

I recently bought and installed a garage door opener. During that process the door was damaged while I was trying to level it.
There is a crack about 1/3 of the width in on one end that has caused one side to raise up about 3/4". From there that section that raised up is actually sinking so the other end is lower. Because of that I only need to remove concrete a distance of perhaps 18"
I hired a guy to install the door and need to figure out a way to level that crack in a hurry. He wants to install the door tomorrow. I don't need to do the whole job right away, just enough that he can adjust the door properly.

Any suggestions?
I know there are geniuses amongst you.

[Bill Jobe]

Well, George, the crack has always been there and a weather strip along the bottom has pretty much sealed the door until just recently. Now it is too high for that to work.
Whoever installed the last door did not secure the track as close as it should have been and I noticed that on one end the cable was not snug like the other.
So, I decided to try to adjust the tracks closer to the door on both ends and try to level it up in the process. I ran into problems and ended up damaging the track on one side.
The door needed replacing anyhow so I decided to just open my wallet and let a pro do the job.
I assumed, incorrectly, that grinding off a bit of a section of concrete that sticks up was doable for the average homeowner.
Now with door installation just 24 hours away I have come to realize that I am not the average homeowner.

I'll get you a pic.

[Lee Schierer]

You can cut the concrete with a Evolution 7-1/4-in Wet or Dry Continuous Diamond Circular Saw Blade and a skill saw. I have cut concrete and pavers with this blade. It works wet or dry. Makes lots of noise and dust so use your ear plugs and dust mask.

Make shallow cuts in rows and chip out ribs in between with a hammer.

[Bill Jobe]

John, I was typing when your post came in.
While I agree that it should be fixed right before the door is installed the wife does not. She wants her garage back. Has little patience and just wants me to "get 'er done".

I just want to lower the high spot enough so he can adjust it correctly. This guy is good and also, busy. I grabbed his Friday install thinking I could figure something out.
I can't see any reason not to have it installed prior to repairing the entire floor, unless you have reason to believe it would be a big mistake. He will make sure, if I can make it fairly level, that no harm will come to the door, then I can have the entire crack repaired by a pro.
He also said he could install the door, then fix the floor, and that he'd then come back and do anymore needed adjustments.

In the pic the section on the right is falling away, causing its edge to rise up. I just need to get it down level where the door will sit.

[Bill Jobe]

Lee, that was exactly what I was considering doing. I have a shop vac and a 2hp DC ready to go and will provide water as best I can.
Anything I should pay special attention to using your method?

[Bill Jobe]

By the way, when I bought my Rigid shop vac I discovered that the hose on my old Craftsman fit perfectly into the exhaust port on the Rigid. I found this to be a great way to use the vac and exhaust it to the outside where the more dangerous micro particals can be blown as well as not blowing dust around in the garage while using it. I also use a section of pvc or such to get it even farther away.

[Carlos Alvarez]

Diamond blade in a grinder would be my choice. It's fast work, but dusty. I've never used water or a vacuum, but wear protection and have a fan blowing the dust away. I was just doing a bunch of solid concrete block work yesterday and it still amuses me how crazy fast these diamond blades in a grinder can make a cut. I just picked up some generic $13 blade at Lowes and have made a LOT of cuts with it.

[John K Jordan]

What worries me is the part about "From there that section that raised up is actually sinking so the other end is lower."

If this means some part of the slab is sinking lower than the rest of the floor causing the piece to pivot and raise one end, why is it sinking? How quick did it sink? Is there any reason to think the "other end" could continue to sink, say with the weight of a car driving over it? A neighbor had a stand-alone garage and one back corner and side started to sink slowly causing that end of the entire building to sink. This cracked the slab and the other end pivoted up. It turns out that the people who built the garage either did not understand or did not care that you cannot build on fill without proper preparation. It was easier to start over than fix it so he tore down the garage.

If you believe everything under your slab is now stable and nothing else will ever move, yes cut off the part the sticks up, patch the part that sank and live long and prosper (and keep an eye on it). Otherwise, it is not possible to engineer a long-term solution without more information or inspection.

It's fairly easy to cut concrete with the right tools. I have industrial strength rotary hammers for drills and chisels. I can quickly get close then surface grind to make it pretty.

[Bill Jobe]

Yes, one side of the garage floor is slowly sinking. It was cracked when we bought the house but there was no settling apparent. I'm going to have a pro look at it.

I've always had to be careful with water buildup on the outside. There's a downspout on that corner and I put the larger size on it and make sure the pipe extends out far enough.
Unfortunately, my wife has a large flower bed there, too, so I made sure years ago that the ground slopes away on that side of the garage.
Buy the crack takes in water from above and that freezes and thaws which keeps moving the slab up and down.

So, I think I will have to dig deep in my pockets and have something done about it.
Things just seem to sneak up on you when it happens so slowly.
I just hope I'm not living on a sink hole waiting to open up.

[Bill Jobe]

Forgot to mention I bought a diamond saw blade and was able to take enough off so that whole side is below level.

[Myk Rian]

He also said he could install the door, then fix the floor, and that he'd then come back and do anymore needed adjustments.

So, what's the problem? Let him do it.

[Bill Jobe]

Well, I have a new garage door and I love it. The independent installer I hired replaced every nut and bolt that did not come with the opener. He did an excellent job. You can hardly hear it open and close.
He replaced my door with a CHI steel unit that has an R rating of almost 10 and has a fully weather sealed top and sides.

However, my concrete problem is perhaps much worse than I thought. Because I cut the high spot down you can clearly see that BOTH slabs were raised at the crack. It wasn't evident before seeing the door sit flat on the concrete that the larger area of the slab, the one closest to the house, has also raised up and appears to be sinking, as well.
Not sure what to think of that....other than my sink hole comment. Seems odd that the 2 pieces are raising up in the middle.
What think ye ?

[John K Jordan]

There are several things I can think of that can force concrete upwards. One is a tree root, even if the tree is some distance away. Another is water entry under the slab and freeze/thaw cycle if you live in an area with severe cold.

Insufficiently supported and compacted base (lazy contractors) can let one end of a slab sink and pivot the other end up. Burrowing animals can undermine anything (when I bought this place there were so many groundhog tunnels under one part of the barn my foot fell through into one.) Underground water flow can slowly erode solid ground or even rock under anything - I made many cave dives in sink holes in Florida that opened up into subterranean creeks, some large and many miles long.

A geologist can tell if you live on karst. I live on such a ridge and there are four large sinkholes down the ridge that I know of. One is big enough to hold a 4-story office building. In the nearby city of Oak Ridge all the houses on one street were condemned when they started to sink into the ground.

I'm not trying to be an alarmist, but if it were my house I'd get someone to check it soon. There are too many possibilities and too much risk to guess or ignore and hope it will go away.

JKJ

Well, I have a new garage door and I love it. The independent installer I hired replaced every nut and bolt that did not come with the opener. He did an excellent job. You can hardly hear it open and close.
He replaced my door with a CHI steel unit that has an R rating of almost 10 and has a fully weather sealed top and sides.

However, my concrete problem is perhaps much worse than I thought. Because I cut the high spot down you can clearly see that BOTH slabs were raised at the crack. It wasn't evident before seeing the door sit flat on the concrete that the larger area of the slab, the one closest to the house, has also raised up and appears to be sinking, as well.
Not sure what to think of that....other than my sink hole comment. Seems odd that the 2 pieces are raising up in the middle.
What think ye ?