# Driveway Cross Section



## 123pugsy (Oct 6, 2012)

I need to submit a cross section drawing for my driveway for the site plan approval.

I need to take away up 15" of material to achieve the req'd 2% grade but that's not really the issue. The point is the old asphalt/concrete/pavers (yes, three different materials on the same driveway) will be removed and scraped down to old compacted clay/soil/dirt.

What are the standard materials used and how much thickness of each gets laid. If I know this, I can finish my drawing. Also good to know when getting quotes and actually having it done.

I also need to build a curb at the outer edge of the driveway to keep water from running into the neighbors yard. Does the bottom of the curb get poured on the same level as the bottom of the driveway or does it need to go deeper or something?

This has to appear on my drawing as well.

Thanks,


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## Bondo (Dec 8, 2007)

123pugsy said:


> I need to submit a cross section drawing for my driveway for the site plan approval.
> 
> I need to take away up 15" of material to achieve the req'd 2% grade but that's not really the issue. The point is the old asphalt/concrete/pavers (yes, three different materials on the same driveway) will be removed and scraped down to old compacted clay/soil/dirt.
> 
> ...


Ayuh,.... 'round here, a standard duty residential driveway would consist of 10/ 12" of crushed limestone, compacted, with a 2"- 2, 1/2" blacktop cap,...

If in Clay, the bouncy stuff, a sheet of fabric should be added, under the limestone bridge,....

Yer gutter's gonna need some visual,... got some pictures,...
hint,... water flows Downhill,....


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## ront02769 (Nov 28, 2008)

Can't tell withou digging a piece of the asphalt...or drilling and measuring. Worked on a site putting in fence posts couple of weeks back through asphalt......and found that where we started it was an easy 2" thick.....but further along ended up around FIVE! Happy days! Ron


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## 123pugsy (Oct 6, 2012)

Thanks.

The engineer is insisting on a 2% grade from the garage slab to the turn in the driveway which goes down a nice hill. There is a seam in the asphalt just down from the top of the turn where the city owned bottom section begins. I will stop there. It is low enough at that point to achieve the grade on my property without touching the city property. On the right is the neighbors side yard about 4' down. That's where the new curb will go following the lowered driveway so the curb will be running at 2% along it also. (downhill is my friend)

The red lines represent how we need to scrape out some soil to get low enough to meet the new grade.

As for soil hardness, we have clay/silty/gravelly hard soil with a PSF of 4000 I believe. Of course the winter summer cycles may have bearing on the thickness of substrate??

This sketch, although rough is a very close representation of the conditions. Level pad beside the house, some pavers sloping down towards the garage and asphalt on a grade to the turn at the corner and then a steep hill on the bottom of the driveway.


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## Bondo (Dec 8, 2007)

Ayuh,.... Of course the 1st step is to dig out all that's there now,.....

Finish grade should be set string line straight from both corners of both buildin's to the lower inside point yer gonna tie into the City's blacktop,...
Sub-grade, just over a foot below that point,...
For the fabric, 'n crushed stone,...

For the Curb, a Slip-form curbin' machine, like the cities use, only smaller would be the cat's azz,...
It could be footered, then formed, but Alota wood, steel, 'n Labor,...

The slip-form Operator will tell ya how far, below finish grade to set the sub-grade,...

In My experience, blacktop curbs, just Don't hold up well, at All,....


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## 123pugsy (Oct 6, 2012)

Thanks. 

Ya, concrete curb for sure. Asphalt at edges always starts crumbling away.

Do I need 2% from the wall to the right or just a small slope? 2% from the house across the driveway is 5" over 20-1/2'. Seems like a lot.


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## Msradell (Sep 1, 2011)

You really don't need 2% slope to get water to flow, as long as you have a slope, even 1% of the water will be going in the right direction. The only problem is how flat the driveway itself is. A 2% slope will overcome any slight deviations and flatness of the page surface. Did you get the 2% figure from local code officials, in which case it would be required or did you get it someplace else?

Also, why you starting the new paving the far below where the existing paving is? You could certainly get a 2% slope without excavating anywhere near that much material.


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## 123pugsy (Oct 6, 2012)

If you look at the existing conditions in the first sketch, you'll see the garage is lower than the slab beside the house. The 2% slope must start at the garage. Yes, this is the AHJ's requirement before I can get a building permit. I also need to run the downspouts from the garage onto this new slope to get the water out to the street.

If I have 2% from the garage moving forward, 1% from the house going outwards, water would move for sure then.

Is there anyone here that lays asphalt and can tell me how they would pave beside a house if the driveway was on a grade towards the street? I know they would slope it but how much?
1% as has been suggested? That would be much nicer. I'd like less if possible, just enough to keep the water away from the foundation.


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## Bondo (Dec 8, 2007)

123pugsy said:


> If you look at the existing conditions in the first sketch, you'll see the garage is lower than the slab beside the house. The 2% slope must start at the garage. Yes, this is the AHJ's requirement before I can get a building permit. I also need to run the downspouts from the garage onto this new slope to get the water out to the street.
> 
> If I have 2% from the garage moving forward, 1% from the house going outwards, water would move for sure then.
> 
> ...


Ayuh,.... That's what I've been tryin' to do,....

Any pitch, greater that dead level will drain,....


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## landfillwizard (Feb 21, 2014)

To get an idea how much 2% grade is, look down the road and the lane you are driving in is ~2% grade (¼"/1') 5" of fall in 20' is not really too bad. The way the contractor will pave this section is to set up the subgrade at 2% and then put in the base material to follow that grade. He will also pave using that grade. What type of material and how deep will be place for base and for the asphalt pavement?


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## 123pugsy (Oct 6, 2012)

landfillwizard said:


> What type of material and how deep will be place for base and for the asphalt pavement?


This is an unknown for me. I have to submit a cross section drawing for approval and am trying to figure out what to draw.

I think I will email this cross section and ask him if it's OK?


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