sinking driveway

[Joe Skinner]

My driveway is sinking where it meets the sidewalk and lifting near the garage door. This happened to my neighbor and the city fixed it because there was a manhole cover involved. I too have a manhole cover on the side walk right next to the sinkage, so I call the city. They looked at it and said it was my responsibility because the sidewalk is not sinking as was the case with the neighbor. When it snowed yesterday, I noticed the snow was melting on the sidewalk and most of the dirveway, except where the hole underneath is. If the non-melted snow is an indication of how big this hole is, it is a big one.

So my question is, how do I go about getting this fixed? I don't even have a clue as to where and how to find a contractor. Is this something I can do most of the work and just have the cement poured? What sort of costs am I looking at to have a 20x25 driveway replaced? I am in the Fort Worth, TX area.

[Cliff Rohrabacher]

Wouldn't if be good to know why the land is moving?

If the drive is concrete just mix some and pour and trowel or screed. If it asphalt you need more asphalt, and you need to prep or pull the old asphalt.

[Lee Schierer]

There are companies that specialize in raising sinking concrete. They will put a hose under the low spot and pump in concrete under pressure, lifting the sunken area. The pumped in concrete hardens and the surface stays put. It won't work in all instances and I wouldn't think it would be a cheap date, but probably cheaper than tearing out the existing and repaving. Troweling concrete on top is like to crack and break off rather quickly unless the layer is really thick and you can properly score the underlaying surface so the new concrete will adhere.

[Ken Fitzgerald]

Joe,

I have raised concrete stairs by just taking gravel and using a 6' long 1" diameter bar.....compacting gravel underneath the stairs.........dig a hole beside the offending stairway.....up against the stairway.....and slightly under the offending stairway.....throw some gravel under....and tamp it using the rod.......more gravel .....tamp/compact in.....eventually the compacted gravel under it will raise it to the level you want. I actually raised the front porch on my house back to level doing that....raised it 2" in a matter of an hour or so.

I helped a neighbor do it and an friend used the same method on his sidewalk on his summer home....

[Stephen Beckham]

Joe,

We had to have a company come do our basement - UDI (United Dynamics I believe) - and I couldn't believe how many companies out there do this kind of work. They usually give free estimates...

If it's a big slab - I'd call someone - if it's just a small piece - Ken's method sounds like punishment, but worth the savings...

[Chris Padilla]

Where is your water main?

The reason I ask is that my boss recently had a problem with his driveway sinking...turned out it was a leaky water main...probably for several years because a small one was found. The city fixed it all but he was having a new driveway poured anyway (at his own expense).

Since your whole slab is moving, I suspect something rather dire going on under it.

[Scott Long]

What kind of manhole is it, sewer, water, or storm.

If it is sewer you might want to take a look and see if the connection going to the manhole is not cracked and eroding the soils from under your driveway.

To answer your question I would over excavate the affected area and fill the hole with modified stone and pack it down well and replace the blacktop or concrete.

[Lee Koepke]

I think there is something else driving this. Driveways dont usually sink like that. Previous poster makes a valid point .. the manhole and junction box may be just fine, but the inlets may have a problem. they should be able to inspect that to verify that you dont have storm ( or worse, sanitary ) sewage leaking into the ground.

Water mains should be seperated from any storm or sanitary mains by 10 feet or so, but that doesnt mean you dont have water leak nearby either.

If it were me, I would want to know the cause of the problem was fixed, because replacing a driveway wont be cheap, and you dont want to do it more than once.

[Joe Skinner]

I have already had the city out to look at it and they say it is not leaking, but you never know if they are just saying that so they don't have to replace a driveway.

It is a concrete driveway and this problem started about a year ago and has been progressively worse. The corner has dropped about 10" and I can stick a hole broom handle into the hole under the sidewalk. The city guy said it was poor ground prep, but no other driveway on the block is doing this and it is all the same builder. He did say that if the sidewalk drops, then it will be a safety hazard and they would have to respond to that, but not if it is just my driveway. I have been parking on the sidewalk over the hole for about 6 months, but I don't think my Ranger is heavy enough to drop the sidewalk.

[Lee Koepke]

I have already had the city out to look at it and they say it is not leaking, but you never know if they are just saying that so they don't have to replace a driveway.

It is a concrete driveway and this problem started about a year ago and has been progressively worse. The corner has dropped about 10" and I can stick a hole broom handle into the hole under the sidewalk. The city guy said it was poor ground prep, but no other driveway on the block is doing this and it is all the same builder. He did say that if the sidewalk drops, then it will be a safety hazard and they would have to respond to that, but not if it is just my driveway. I have been parking on the sidewalk over the hole for about 6 months, but I don't think my Ranger is heavy enough to drop the sidewalk.
man that doesnt sound right at all. I am a contractor and I have seen poor subgrade prep and you dont get 10" of settling unless something below is giving ground.

Poor compaction would create potholes in asphalt, but 4" of concrete takes alot to shift that much.

Be persistant with the city because something is causing this.

[Chris Padilla]

Joe,

You in Cali somewhere and buy the unlucky spot over a sinkhole?! ;) Just funnin' ya but something isn't right and I hope it doesn't cost you your next vacation to right it. Can you post any pictures...we like pictures. :)

[Joe Skinner]

Too dark for pictures right now.

It is a sewer cover about 2ft from where the driveway is sinking. Now that we have been discussing it, I think it is a problem with the sewer line. I have a brick mailbox on a small slab that is also sinking. The mailbox is about 15ft from the manhole cover. I guess it is time to get on the city again.

Any idea what a new driveway costs? I should probably have the money just in case the city wont pay that portion.

[Cliff Rohrabacher]

Too dark for pictures right now.

It is a sewer cover about 2ft from where the driveway is sinking. Now that we have been discussing it, I think it is a problem with the sewer line. I have a brick mailbox on a small slab that is also sinking. The mailbox is about 15ft from the manhole cover. I guess it is time to get on the city again.

Any idea what a new driveway costs? I should probably have the money just in case the city wont pay that portion.



The city is paying to Process all the dirt they are washing away - assuming it's making it to the septic treatment plant.

[Jim O'Dell]

Joe, I guess if you are going to have to replace the driveway, drill a hole in the concrete, and use a long thin rod of some sort to see how much "space" is under the driveway. The smell might also show that it is the sewer causing the problem, and then the city will have no way out. Also, ask for a city engineer to come look at the problem, not just a worker.
If they still insist it is not their problem, and was in the prepping of the site, ask for it in writing. If your home is fairly new, go to the builder, if they are still in business, and have them come look at the problem, and show them the write up from the city. Maybe let the two of them duke it out. ;)
Sorry you're having problems. Hope you can get it straightened out. Wish I knew someone local that could help you. Jim.

ps. If there is a manhole cover, then most likely it is for storm drainage. Most sewers are sealed.

[James Suzda]

I don't think the "City" is going claim responsibility, rush in, and say "Gee we are sorry about that and we'll get right on it." They are going to fight paying for this as long as they can. Besides, if they screwed up on your neighbor's sewer, there is a good chance the City's contractor screwed up on yours also!

Just where in the heck did the soil go if it didn't go down the city's sewer what happened to it?? Fill just doesn't go away on it's own. Also, how long has your driveway been there before it started to sink?
Just my 2 cents.

As for just "mud jacking" the concrete I don't think it's going to work. If there is no base, under the concrete what is going to keep the new fill in place. It would be interesting to drill a hole in the concrete and push a rod down to see if there is anything under there. But, if you do decide to try this, there are companies that can drill small holes in the concrete and pump in some expanding foam that works pretty good. (Back in my former life, they had to do this to a brand new floating warehouse floor in which the floor sunk.)
Just my 2 cents!

[Curt Fuller]

Too dark for pictures right now.

It is a sewer cover about 2ft from where the driveway is sinking. Now that we have been discussing it, I think it is a problem with the sewer line. I have a brick mailbox on a small slab that is also sinking. The mailbox is about 15ft from the manhole cover. I guess it is time to get on the city again.

Any idea what a new driveway costs? I should probably have the money just in case the city wont pay that portion.

You didn't mention how old the home is or how long the subdivision has been there. But for something to sink, settle, or otherwise have that much movement is a more serious problem than just replacing the driveway. If the house is fairly new, it's possible that the sewer, water, or other utility trenches weren't properly compacted when the development work was done. They might do things different in Tejas but around here water valves, storm sewer manholes, etc are in the street. The water meter for your house is what would usually be in the area of the park strip or inside the sidewalk and settling would be the result of a poor compaction job when the water line to the house was installed or else a leak. If the leak were on your side of the meter you'd know by your water bill. Also sewer and storm sewer lines are gravity flow, not under pressure, so unless there was a pipe that was completely severed and not just leaking it wouldn't wash a sinkhole. But a pressurized water main would wash away a lot of soil. I would think the city would want to investigate the problem.