Gravel layer thickness

[RocketJSquirrel]

I am going to cut a swale (very shallow ditch) to channel water away from my detached garage. It will run across one side of the garage a few feet from the building. After I cut the swale, I am going to finish off the area with gravel. My soil is well-compacted clay. The gravel will be crushed limestone (I think it is), say like .5 to 1.5 inch stones, with no fines. Since this area is not a driving area, this will be more like putting in landscaping than a driveway. But it will get parked on sometimes. What is the minimum thickness I should use for the gravel? I am hoping to keep it to 3 inches or so. thanks.

 

[Green_in_MI]

Why bother with gravel if you are rarely going to park on it. I would cut the ditch and reseed with grass. The grass will prevent any erosion. If you leave it as some sort of stone it will alway be subject to erosion.

 

[Gary_in_Indiana]

Green is right. Unless there is some reason you can't or don't want to mow it ever, keep it grass. It'll be easier to maintain and far less expensive, too. /w3tcompact/icons/wink.gif/w3tcompact/icons/smile.gif

 

[gerard]

I did what you describe and since my swale crossed the driveway into the barn I had to use gravel, not grass. I just have a thin, maybe one inch covering of gravel and the water percolates through it just fine. The ground was already very compacted.

 

[AZMike]

The minimum depth of rock depends on what you want to do with it. If it is just for looks, whatever looks good to you should work.

If you want to park on it, since it has no fines in it, you should keep the depth of rock to about 3-4 inches. If you go much deeper than that and you park cars or light trucks on it you may find yourself getting stuck in the loose rock or just displacing the rock as you drive around on it.

Generally speaking you want to have fines in it if you park on it. If you want to have water run through it too, put your clean rock on the bottom and rock with fines in it on top. Of course you are usually talking about an overall depth of rock here of at least 12-18 inches to allow enough clean rock and rock with fines to each do their own thing.

Sounds like a fun project, good luck!