Driveway Sinking

[chasineyes]

Finally decided to check out the driveway issue (I know should have done it sooner). But here is what I found. I have a asphalt driveway that has sunk almost 3 inches from the garage floor. Upon examining the sink, I hit one corner with my hammer and a 3"x5" hole! developed! I then noticed that almost 4 FEET of fill is missing/eroded from under the garage floor/asphalt apron. Ironically I had 3 wheelbarrows of sand around so I dump 1 full wheelbarrow into the "opening" along with using the garden hose to help "fill" the voids.

MY QUESTION IS...do I need someone to "MudJack" the floor or just repair the asphalt apron? ALso do you think I would be better off (cost wise) just installing a new driveway vs. just the apron???

THanks!! and Happy Labor DAY!!!!!!!!!!

[WalleyeChaser]

Sorry to hijack, but I think I have the same problem. I will have to keep an eye on this!

[CAMAN]

I don't believe mudjacking works very well with asphalt. I have a similar issue with my driveway and since the rest of the driveway is in good shape I will be cutting out about 3 feet from the garage, replacing the washed out fill and repacking it, then installing a concrete apron. Most of my neighbors have done similar.

[Tom7227]

About 20 years ago I had the same problem. What I found was that the block footings were unfilled and the material had started to go down into those voids. I was able to fill some of them but I didn't get very far into the garage and some of that area has sunk about 3/4 of an inch. Short of ripping up the concrete and filling it all in I don't think there's a solution. I don't know why those blocks aren't filled in routinely. Maybe someone with some knowledge can explain.

[chasineyes]

I know my problem is caused by the downspout draining right in that corner. I should have dug an underground drain tile for it instead of letting it pool up by that corner. Now I need to see how bad this is!

Granted I now have a new weekend project to do....

[Tom7227]

It can be worse. Once my new concrete driveway as in place things looked pretty but in the winter the driveway rose about 2 inches. It got to the point where I nearly couldn't get my truck in the garage. Sort of luckily the concrete spalled and had to be replaced - by the contractor and at his expense. Between the time he pulled the old one out and started on the new one I rented a huge ditch witch and put in about 150 feet of drain tile. I figured that I had to get a lot of water out from under that driveway to prevent it from rising. It was an incredible amount of work but it did solve the problem.

[vister]

I don't know why those blocks aren't filled in routinely. Maybe someone with some knowledge can explain.

Very good question. They wouldn't need to be core filled if the foundation was simply waterproofed. Sprayed with hot tar. Then back filled. Pouring the core of blocks with concrete, dry mix, mortar, etc, would cost money. Waterproofing costs money. And with all the dumb building codes we have to deal with nowadays, I can't believe someone in a chair in a 40th floor climate controlled suite, has thought "hmmm, cinder blocks corrode below grade, maybe we should make contractors waterproof foundations".