# Steep gravel driveway - washed stone?



## BigJim (Sep 2, 2008)

I would be concerned with gravel that size washing. If it were mine I would go with crushed limestone as it will set up like concrete but there is no guarantee that even that won't wash.


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## High Gear (Nov 30, 2009)

I had a gravel drive of around a 12% slope. ( divide rise by run )

Fierce storms would wash wicked ruts, paving solved the problem.


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## Bondo (Dec 8, 2007)

> I would like to dress the entire drive with a top coat of washed 1/2" stone, but someone told me this would cause wheel spin.


Ayuh,... 1/2" stone with no fines will be like drivin' on Marbles....


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## concretemasonry (Oct 10, 2006)

You need angular aggregate and some fines to hold everything together. Otherwise it will be like driving on bbbs and rock will roll down your steep slope. You probably don't have a 30 degree slope because most people radically over estimate the degree of slope, but whatever it is you are using the wrong surface material. Even though your subaru makes it up fine, each time some aggregate is moved downhill.

Dick


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## BRO931 (Jul 12, 2010)

concretemasonry said:


> You need angular aggregate and some fines to hold everything together. Otherwise it will be like driving on bbbs and rock will roll down your steep slope. You probably don't have a 30 degree slope because most people radically over estimate the degree of slope, but whatever it is you are using the wrong surface material. Even though your subaru makes it up fine, each time some aggregate is moved downhill.
> 
> Dick


Thanks for the info Dick (a.k.a. concretemasonry). The crusher-run I have now seems to be the mix of angular aggregate with fines that you suggest. But then you say that, whatever the slope is, I'm using the wrong surface material. Let me take a wild guess at what the right material might be. Could it be............... concrete?

I would consider pouring concrete if it were not for the fact that heavy equipment and 4" concrete slabs don't get along well. I'm still working on refurbishing this place and will likely have heavy material deliveries. I can't see pouring 8-12" highway-grade slabs. Maybe some sort of concrete blocks and gravel might work. The problem with this crusher run is the fines are washing down the hill. 

BTW, the drive rises 40' over its entire 200' length, but one 30' section does rise about 10' (33%?). Would a 6/12 pitch roof have a 50% slope, or would that be 44.7% (6' / 13.4' rafter length)?


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