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  1. #1
    Join Date
    Sep 2007
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    Default Grading Information

    I'm having trouble finding information on grading (most books either cover planting new plants or building retaining walls - but no site preaparation...). I have an L shaped ranch house and I'm trying to grade the front yard away from the house in preparation for the rest of the landscaping. The soil is heavy clay and the previous owners had done some quick landscaping which brought in some new soil, that raised the finish grade above the bottom of the siding. I've dug out 3-4 feet away from the house, but I'm not sure exactly how to finish it off. If someone can recommend a good text I'd be very appreciative, but I'd also welcome any thoughts on the following questions:

    1. How far below my cedar siding should the final grade be? (assume 2 to 3 inches of mulch).
    2. Do I need to pitch away from the both legs of the "L" shaped ranch, or can it pitch directly to the street? (See photos below)
    3. What pitch do I need to grade to? 1/4" per foot?
    4. How far out from the foundation do I need to continue that pitch? 5 feet, 10 feet, all the way to the street?
    5. When amending heavy clay soil, how deep do I need to till?
    6. What equipment should I look for at rental yards for this job?

    Here is a plotmap, I'm trying to grade the upper-left quadrant of the drawing. The street is probably 3 feet lower than the entrance to the house: http://www.dvhart.com/sites/www.dvha.../309_large.png

    Here are some pictures to provide the curious with some context of the total project:
    http://www.dvhart.com/content/remodel_0

    Thanks for reading!

  2. #2
    Join Date
    Aug 2007
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    Default Re: Grading Information

    1. How far below my cedar siding should the final grade be? (assume 2 to 3 inches of mulch).
    3" to 4" minimum below the siding with your finish layer. Accounting for your mulch, the soil should be graded 5" to 6" below the siding.

    2. Do I need to pitch away from the both legs of the "L" shaped ranch, or can it pitch directly to the street? (See photos below)
    I would recommend pitching away from the structure in all directions AND pitching towards the street. This way you won't have pooling around the house and you'll also get natural drainage to the street. Additionally, a drain could be run the length of the property to the street to collect the water down the sides of the house/property and direct it appropriately.
    3. What pitch do I need to grade to? 1/4" per foot?
    This would be sufficient, particularly over a hardpan soil as you've described.
    4. How far out from the foundation do I need to continue that pitch? 5 feet, 10 feet, all the way to the street?
    Two options, you can go all the way to the street OR you could go about half way and install drainage to continue it. By going all the way you'll eliminate pooling and problem areas in the future.
    5. When amending heavy clay soil, how deep do I need to till?
    Depends on what you're trying to accomplish. For lawns, you don't need to amend any deeper than about 6", however for flower beds up to 12" would be better because of the root depth of the plantings over grass. A caution, however, is that when you amend the soil, you'll be creating a basin in the hardpan for water to collect. Perimeter beds won't be an issue, it will be along the house that you want to be careful of this. The cure would be to amend the soil to the same depth in all areas, so that a basin isn't created in the hardpan.
    6. What equipment should I look for at rental yards for this job?
    That would depend on your stamina. I would at the very least rent a commercial rototiller, though with the amount of tilling, amending, and grading you're looking at, a small tractor with a loader and tiller would probably suit you better and make the job easier and faster. Not knowing the lay of your property or utilities, I would recommend a call to USA, which is a nationwide company that comes to you for free to locate all underground utilities. If you've got a sprinkler system, it is likely going to be destroyed in the grading and tilling process, if you don't have irrigation, now would be a good time to install it (after grading and amending ).
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  3. #3
    Join Date
    Sep 2007
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    21

    Default Re: Grading Information

    A. Spruce,

    Thanks for the reply, I really appreciate the input. Sounds like I should grade all the way to the street, in both directions. The part about the basins in hardpan concerns me though. I have a few plantings (two japanese maples and a couple "rodies") that I was hoping not to have to move (perhaps I need to give up on that wish?). There is also a very large split trunk alder near the house whose root system would probably be destroyed if I dug down that deep - my wife hates that tree anyway... Hrm... So many things to consider.

    Regarding using a rototiller - how exactly do you determine a 1/4" per foot slope over rototilled hardpan? The intact hardpan is well below the surface, and the surface is ... well... tilled. Maybe I'm just making this harder than it needs to be. Do I just rototill and then move the dirt around until I can detect proper slope over say a 10' span at a time?

    Thanks again for your time and experience, much appreciated.

  4. #4
    Join Date
    Aug 2007
    Location
    Maryland
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    1,256

    Default Re: Grading Information

    Spruces info is all good, I would only add that sometimes creating a shallow swale out from the house 12' or more away from the house is a good way to direct water away from & around the house depending on the existing layout. For instance if the grade in the back is higher than the front & street elevation. By swale I don't mean a ditch, but rather a slight change in the direction of flow.
    If you have major changes to make, a bobcat & someone who knows how to use it is handy. Equipment operators seem to charge a lot, but when you consider the experience & equipment & the time savings it can be a bargain.
    Rhodies & maples can be moved. Dig wide,not deep & don't plant any deeper than they are now. Amend the soil with some compost, but not a lot since you want the roots to go out into the native soil eventually. Early spring or early fall is probably better to move, but if you can wait until the new growth has hardened off you should be able to move if the plants are kept watered.
    About the alder we have a saying at my house, "When Mamma's happy, everybody's happy."

  5. #5
    Join Date
    Aug 2007
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    Default Re: Grading Information

    Quote Originally Posted by dvhart View Post
    A. Spruce,

    Thanks for the reply, I really appreciate the input. Sounds like I should grade all the way to the street, in both directions. The part about the basins in hardpan concerns me though. I have a few plantings (two japanese maples and a couple "rodies") that I was hoping not to have to move (perhaps I need to give up on that wish?). There is also a very large split trunk alder near the house whose root system would probably be destroyed if I dug down that deep - my wife hates that tree anyway... Hrm... So many things to consider.

    Regarding using a rototiller - how exactly do you determine a 1/4" per foot slope over rototilled hardpan? The intact hardpan is well below the surface, and the surface is ... well... tilled. Maybe I'm just making this harder than it needs to be. Do I just rototill and then move the dirt around until I can detect proper slope over say a 10' span at a time?

    Thanks again for your time and experience, much appreciated.
    What I would do is grade the area first, using the tiller to break the soil in the high spots just enough so that it can be graded as needed. Once the area is sloped the way you want it, then work it with the tiller and amendments to whatever depth you want. Plan your work ahead of time so that if you need to get rid of some soil you are prepared to do so, if you can move it to other locations, that's fine too.

    You can keep tabs on your progress with a water level, which is just a length of clear tubing and a water vessel. Water will find it's own level, so set the vessel on a table near the house, attach the tubing to it, then attach the other end of the tubing up a 6' tall stick. you walk the stick around the yard and note the level of the water in the tube, this will find all your high and low points. Just make sure your tubing is long enough to reach all the points from the house to the street. An alternative would be to rent a builders level, which is basically just a gun sight mounted to a tripod. you look through the sight to a "story pole" - a big measuring stick - to find your levels.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  6. #6
    Join Date
    Jun 2007
    Location
    near St. Paul, MN
    Posts
    166

    Default Re: Grading Information

    My parentsí old house was built in heavy clay. Even though the lawn was graded properly they sometimes had problems with water coming into the basement. The problem was that the clay soil would shrink as it dried and pull away from the house. Then when it rained there was an easy avenue for the water to get right up at the foundation. It would run into the window wells and then come in the basement windows.

    If your soil is really heavy, too, watch out for this. The only really good solution is to put in a drain tile system to take the water away.

  7. #7
    Join Date
    Sep 2007
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    21

    Default Re: Grading Information

    I really appreciate all the info everyone. I called up a local rental yard, they discussed mini excavators and mini steer loaders with me, but after reading A. Spruce's idea on the rototiller, I think I may get by with just the tiller - and maybe the very smallest bobcat steer loader just to push the loose stuff around while getting the desired slope.

    One remaining question though (for now, others are sure to arise!). Ed21 mentioned hiring an "equipment operator"... how do I go about finding one? Do I just go through various landscaping contractors, or can I find a generic "steer loader operator"? What do I look under?

    Thanks again.

  8. #8
    Join Date
    Aug 2007
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    6,614

    Default Re: Grading Information

    Quote Originally Posted by dvhart View Post
    One remaining question though (for now, others are sure to arise!). Ed21 mentioned hiring an "equipment operator"... how do I go about finding one? Do I just go through various landscaping contractors, or can I find a generic "steer loader operator"? What do I look under?

    Thanks again.
    I would say look for an excavation contractor, there should be a section in your phone book for them.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  9. #9
    Join Date
    Sep 2007
    Posts
    21

    Default Re: Grading Information

    OK, I knew there would be at LEAST one more question :-) It was mentioned that I should ammend the soil only slightly (since I want the roots to grow into the natural soil eventually). Given heavy clay as my starting point. I think I'll plan on ammending the top 8" of the soil (per our landscape designer's recommendation - she picked the plants afterall).

    1) How much material do I need per unit area to ammend the clay?
    2) What do I ammend with? (Compost?)
    3) Do I need something to help with drainage? (sand?)

  10. #10
    Join Date
    Aug 2007
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    6,614

    Default Re: Grading Information

    Quote Originally Posted by dvhart View Post
    It was mentioned that I should ammend the soil only slightly (since I want the roots to grow into the natural soil eventually).
    Good plan, otherwise plants can become "root bound" because they don't want to grow out into the existing soil. This is particularly a problem with trees, but shrubbery can experience it as well.

    1) How much material do I need per unit area to ammend the clay?
    2) What do I ammend with? (Compost?)
    Don't worry about exacting figures. Depending upon the material you're using spread a layer 3 to 6 inches deep over the entire surface, then work it into the soil well with the rototiller. The most readily available materials in these parts is municipal compost, compost, and manure.
    • Municipal compost is made from the green waste that the city/county collects from the citizenry. The good things are that it's helping to utilize what would otherwise be filling a landfill, it's cheap, and it's relatively organic (as far as being plant based ). The bad things are that it tends to have inorganic debris that doesn't break down (plastic, and other foreign matter ), and because it's made from municipal wastes, you don't know what types of chemicals people have used on the plant matter prior to tossing it to the street, or what kinds of things were hiding in the debris piles when they were picked up.
    • Bulk compost from a nursery/landscape supply (other than the aforementioned municipal compost ) will be composted of clean plant matter, usually tree bark. It's more expensive because it's "virgin" material that's been composted. It's usually guaranteed to be clean (no debris of any kind ).
    • Manure of any kind will also do the trick. Manure is full of all kinds of beneficial nutrients, and it generally will have straw or wood chips (bedding removed with the poo ) that will help to break up the clay and add organic matter that will break down over time. Many times you can get it free for the hauling.
    The key to breaking up clay soil is to add organic matter. Any one of the listed items will do that and significantly change the composition of the soil

    3) Do I need something to help with drainage? (sand?)
    Other than grading the slope and adding contours to direct surface water where you want it to go, I would say no.


    Keep in mind that as you work the soil and add amendments that you'll be fluffing and adding air which will make the level of the ground seem a bit higher than it will actually be once it settles back down into place. The addition of the organic matter will increase the soil volume a bit too, however it will be virtually imperceptible when all is said and done.

    Hope these comments have helped. Good luck, and report back your progress, keeping in mind that we like to see pictures too.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

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