Driveway Parking Area Construction Help

[GoodGuy]

I have been preparing my site for a driveway parking area. I now have the trees cut & most of the stumps dug out & hauled away. I also have removed a considerable amount of rock, the football,basketball & larger size ones. I am now getting to the point where I need to calculate the grade & determine how to place the material. How much grade do I need to calculate for a 50' area & when I get ready to put down the Class A Gravel, should I put landscape fabric down ? If I use landscape fabric, should it be laid out before my rough base gravel or after I have it levelled ready for the Class A ? How thick should I calculate for the Class A ? I think I have enough to lay 3" so, should I order another couple truck loads or will 3" be enough ? Am I Ok that some topsoil has got mixed in with my base gravel ? Thanks in advance for your help.

 

[Wesdor]

We are building a new home and have a 375' driveway - perhaps similar to your situation. I took out 6" of dirt and then put down the geo fabric. Then added two dump truck loads of rock on top (3" size). Trucks have been driving on it since July 5 and it is getting packed down nicely. By the end of October, I'll have a couple more loads of smaller rock hauled in on top of what is there.

If I read your post correctly, your situation is pretty much like mine. So far this has worked very well for me. Hope this helps.

 

[Toiyabe]

For the grade, 1/4" - 1/2" per foot cross-slope for a gravel road was the rule of thumb when I worked in central New York. For a 50' wide parking area, I would go with 1/2" per foot, knowing nothing else about your situation.

If you are concerned with drainage, make sure that your gravel layer is "daylighted" so that water can flow through the gravel and out the low side. You could also put a perforated pipe along the low side to collect the water if you don't want a drop-off on that side.

Fabric is most usefull when you have a fine-grained (lots of silt or clay) and poorly-drained subgrade. They can prevent that fine material from pumping up into your clean gravel, and also help spread the load on the subgrade. Different fabrics have different capabilities in these regards. The stuff I've seen sold as "landscape fabric" is decent in both regards, but I don't think that term is rigidly defined. If you don't have a mucky subgrade, the fabric will not do much for you, although it's not that expensive either.

 

[Mavrik02]

My landscaper put the fabric down on the ground then added about 4 feet of shale to rough in the grade. Then about 4" of large #3 stone and then about 2" of 2B/2B modified. I need another 2 inches of 2B modifed and I think I will be set for awhile.

Just fyi...my driveway is 440 long and my parking pad is about 150 feet long by 50-70 feet wide.

Water drains right through the stone and shale. The only problem I have is near the top of the pad where there is no shale and the water drains through the clay very slowly. When it rains hard I get a small puddle in that spot. I need to add some of the 2B modified there to build it up (it is a low spot) and that should get the surface above the water (only need to worry about it in heavy rain). If it is still a problem I'll be regrading...

 

[GoodGuy]

I am moving forward with the parking area. The stumps have been removed & large rock removed as well. I have created an approximate grade of 1/2" over 10' towards the existing ditch around the perimeter of the property. My help request now is that I am into a slippery, slimery muck that will suck your boots off (see attached pic). I scraped the topsoil off when creating the grade but maybe it was deeper than I saw. My tractor will not even turn in this mess that is how slimey it is. Should I put the landscape fabric down now or a layer of crushed rock first. If I put crushed rock down, I'm sure it will disappear but maybe that's the point, yes/no ? What are your experiences when creating a good base & working in my type of conditions ? Thanks

 

[HomeBrew2]

Hopefully, you mean 1/2' instead of 1/2" in 10' ...

 

[Toiyabe]

If you've got the grade where you want it, and no big ruts or holes from footprints or tires, then I would put the fabric down directly on the muck. Work from an edge outwards, preferably from solid ground (the driveway?). Try not to disturb the muck by driving on it until you have the fabric and some gravel down on top of it. Keep the tractor as far away from the edge of the improved surface as possible while you're working.

You can also build a work platform by putting some crushed stone directly on top of the muck. That stone will give you more structure if it's above the fabric than below, though.

I agree with HomeBrew2 - 1/2 inch per 10 foot is not much grade - 1/2 foot per 10 foot sounds about right. There's an optimum grade for a gravel surface - too little and it wont shed water, too much and you'll get erosion. 1/2" per foot is my best guess at that optimum. Your mileage may vary.

 

[inveresk]

On crossfall, the previous post is correct. 1/2" in ten feet is only 1 : 240 which will pond. If your photograph is typical of your conditions, better steepen the gradient to 1 : 25 as Toiyabe recommended.

Any soft spots should be dug out and upfilled. No point in throwing good rocks into areas where they'll disappear.

 

[GoodGuy]

Thanks for Input, Appreciate it !
I checked the grade this evening after reading your replies. I have 15" over 88', do you think I'm Ok or do I need make more modifications. Is the general concencious to put the landscape fabric down now as per Toiyabe's suggestion. Toiyabe, unfortunately I have the area rutted up right now but we're suppose to have clear weather for the next few days so I'll stay off it & try to smooth up with my loader ? once things dry out I'll move to the next step. Is the landscape fabric that I get at the local hardware store Ok or shall I be looking for something specfic re the quality. Appreciate your help, folks.

 

[Toiyabe]

15" over 88' is 1:70, which is still likely to pond. Whether ponding is acceptable in that location, I don't know.

The fabric needs to conform to the surface of the subgrade. If it bridges ruts, it'll either shift or tear when it's loaded, neither of which is good.

I've used landscape fabric from Home Depot for a similar application and I've been happy so far. That stuff is "spunbonded" polyester, has fibers that are maybe an inch or two long with a random orientation. It was grey (perhaps for UV resistance) and sold as weedblocker. I've seen similar stuff used in highways, although that was heavier gauge. These fabrics have reasonable strength and filtration capabilites, and it sounds like you need both.

Otherwise, there's woven fabrics and felt-type fabrics. The woven fabrics have good strength, but poor filtration. The felt fabrics have good filtration but poor strength.

With the amount of fabric you're going to need, you may want to try calling up local landscaping or rock-products companies. They may not be cheaper than the hardware store, but they are likely to carry fabric in greater widths, which means you won't have to do as much overlapping. They may also carry fabrics in heavier gauges.