Cold weather raises driveway

[Rebel1]

After maybe a week of temperatures continuously below freezing, day and night, my driveway raises well above the level of the garage's concrete.

The baking soda box is 2" high. The edge of the blacktop closest to the box is raised about 1.5"; about a foot further from the garage, the blacktop is maybe 2" high.

The house is on a slab. Soil in central NJ is somewhat heavy, but not clay-like. The whole property slopes gently down toward the street, which is 100 feet away. (According to Google Earth, the street end of the driveway is 3 feet lower than the garage end.) Behind the garage is a utility room. A little far-fetched that the water under the blacktop gets there by seeping from the back yard under the 28' slab to the start of the blacktop.

I have two good gutters taking roof water away from the blacktop. Each discharges its water at least 12 feet from the sides of the blacktop. One discharges its water about 25 feet closer to the street; the other discharges about where the blacktop meets the garage, but as I said 12 feet to one side.

The driveway is 10 years old. The old one, which was completely ripped out down to bare soil, also showed the same cold-weather behavior.

Even though it's only a cosmetic problem, and the blacktop will be level with the concrete once the weather warms, any ideas how to prevent this seasonal rise and fall?

Thanks,

R1

[DerbyDad03]

I don't have a solution, but I wouldn't call it "only a cosmetic problem". Asphalt is not very strong around the edges. A raised edge like that, especially a sharp edge, seems like it would be subject to cracking off.

Is it safe to assume that you don't drive over this edge when it's raised up? I can't imagine that it could withstand the weight of a car too often before it started to crack.

[CRNG]

On Sun, 02 Feb 2014 11:32:15 -0500, Rebel1 wrote in

My *guess* is that there is a lot of moisture in the soil under the driveway. Does that seem to the case? If so, then maybe figure out how to remove or reduce the moisture??

[micky]

It will go down aga in within a few weeks. If it doesn't you can worry about it then.

This I think you could measure yourself and do a better job than Google earth. Do you have a level, and maybe a laser pointer, or eyes.

This stuff might matter, but the fact that it rains on the ground is probaly of primary importance. IIUC water flows all over the place underground.

It doesn't go up in height, but when it rains here two squares of the sidewalk float. When I stand on one it forces water out from under the sides

Get some big lead weights, maybe 50,000 pounds worth, and put them on the last 10 feet of the driveway. If not lead, get 50,000 pounds of pillows.

He's right. Diving over the edge is going to break it. If you absolutely have to, maybe a steel plate 6 " wide or more and as long as the car is wide, or more, would distribute the weight. But maybe it would just break the edge off in a straight line.

[philoÂÂ]

I'm sure that's the case, as when water freezes it expands.

Good solution would be to move to Arizona.

[clare]

Is there 3 feet of gravel under the blacktop? If not, it WILL heave and buckle and break with freeze-thaw cycles.

[Lab Lover]

"3 feet" of gravel? Where did you come up with that figure? I would love to see a citation. Everything I have seen calls for 8" - 10" of well compacted gravel on top of a solid soil base.

[clare]

Down below the frost line,in a cold winter like this year that's 3 feet even in New Jersey.

[Rebel1]

I put the car in the garage every night, so I do drive over it. And yes, there is a gap of 1.5 inches.

[Rebel1]

No, Arizona is in what many consider to be a permanent drought, as are many other western states. I'd rather have too much water than too little.

Would you believe that in Colorado it is illegal to collect rainwater that falls on your property? I guess they want it to recharge the aquifers, but if you using rain water that you've collected you're not using water withdrawn from the aquifers.

Watch for water right to become a major issue, especially how the water from the Colorado River is allocated.

[Rebel1]

It consistently goes down to the level of the concrete on the warmer weather arrives.

No point in going to surveyor's accuracy. I'm just trying to give a general indication of the slope.

That's really bizarre.

It's an intriguing idea.

[Rebel1]

There is definitely not that much. As I look back at the photos from

2004, I don't see any gravel. The blacktop looks like it's going directly over compacted soil. This is the heart of the problem. I'll know better the next time.

[Lab Lover]

Can you provide any citations where building codes or engineering guidelines specify a 3' base of gravel for an asphalt driveway? I certainly cannot find anything of the sort. The absolute maximum gravel depth recommendation I can find for asphalt below the arctic circle is 12" and that is considered excessive.

[Lab Lover]

Let me suggest you send your picture and question to the engineering department of the National Asphalt Pavement Association. Here is a link to the website:

and the email address for the engineering department

[e-mail]

[hrhofmann]

ight, my driveway raises well above the level of the garage's concrete. htt p://

The baking soda box is

2" high. The edge of the blacktop closest to the box is raised about 1.5"; about a foot further from the garage, the blacktop is maybe 2" high. The ho use is on a slab. Soil in central NJ is somewhat heavy, but not clay-like. The whole property slopes gently down toward the street, which is 100 feet away. (According to Google Earth, the street end of the driveway is 3 feet lower than the garage end.) Behind the garage is a utility room. A little f ar-fetched that the water under the blacktop gets there by seeping from the back yard under the 28' slab to the start of the blacktop. I have two good gutters taking roof water away from the blacktop. Each discharges its wate r at least 12 feet from the sides of the blacktop. One discharges its water about 25 feet closer to the street; the other discharges about where the b lacktop meets the garage, but as I said 12 feet to one side. The driveway i s 10 years old. The old one, which was completely ripped out down to bare s oil, also showed the same cold-weather behavior. Even though it's only a co smetic problem, and the blacktop will be level with the concrete once the w eather warms, any ideas how to prevent this seasonal rise and fall? Thanks, R1

The title of the OP should say freezing weather, not cold weather. Nothing happens until there is freezing weather.

It's pretty obvious that there is no seal between the garage and the drivew ay, so moisture will get into the ground all along the area between the two sides of the driveway whenever it rains. Next year, after the driveway si nks back down, seal the seam so no water can get into the soil right along the edge of the driveay and the garage. Dig something so that any water al ong the edge of the driveway drains rapidly away, to reduce the moisture in the ground along the side of the filled up seam. You will still have some heaving along the edge of the driveway, but nothing like what you have now . It is fairly obvious that the original installation was deficient in hav ing good drainaige for rainwater under and along the edges of the driveway, so you will have to live with that unless you are willing to redo the enti re apron area of the driveway with a proper sand and gravel base.

[Tony Hwang]

Hi, Having extra harsh winter this year, sounds like heaving, will settle down when spring comes.

[micky]

on either one.

And this is not at the bottom of a hilll. It's flat but more like the top of a hill.

[micky]

At least you didn't contribute to the gravel shortage. That's going to be a big issue in 2014 and 15.

[philoÂÂ]

I was just kidding about that. The Winters there are nice but Summers impossible

I read an article on that. I think it's criminal that you could get prosecuted for having a rain barrel.

I've been to Colorado many times and like it though.

[krw]

That's a classical "frost heave". As long as it goes down, you're probably OK. It's not good for the slab but you'll have to take it up to fix it anyway. You need more drainage under it. Remove all clay and replace it with stone, at least 6" of stone. More is better.

As long as it goes down every spring, you can wait for it to fail before you fix it, though. At least I don't know of any fixes that can be done without destroying the slab.

The reason you garage floor doesn't do this is because there is a "frost wall" under the door opening to keep the frost out of the ground under the garage. That's why you see the edge.

Hydrostatic pressure can do amazing things.