Question
I am laying a new lawn on land with very poor natural drainage . I need to fill the plot 12 inches to reach my desired level . What is the best method of drainage and what levels of top soil , gravel and sharpsand etc. is required .

Answer
Good afternoon John:
There are several things to consider when purchasing and installing sod. First and foremost is buying the right grass for your use and location. Some factors to consider when choosing a grass species and / or variety are amount of shade, traffic, level of care, desired quality, cold and drought tolerance. Top soil, gravel and sharp sand is not required if proper soil preparation is achieved.
Measure:
Make a sketch ( Include Measurements) of the area where you plan to establish your lawn. Include the dimensions of sidewalks, parking areas, shrub beds and buildings. They will influence the total amount of sod you need to order. Once you have all of the measurements, calculate the total square footage of lawn area. If you are not sure how to do this, take your drawing and measurements to a local sod supplier. They can help you calculate just how much sod you will need to order.
There are 9 square feet in a "yard" of sod, so if you have, for example, 3,500 square feet of lawn area to plant you will need to order at least 388 yards of sod. 3,500 / 9 = 388. Many companies only sell sod in units of 50 yards per pallet.
Soil Preparation:
Get your soil tested to determine the nutritional status of your soil. Results will also help you determine what soil amendments are needed to ensure a healthy, mature lawn. kill all the weeds and what remaining grass you have by an application of  glyphosate (Round Up). Follow directions on the label. If you have shaded areas consider using bark mulch or ground cover instead of grass in those areas.
Roto-till the existing soil to a depth of 4 to 6 inches to ensure good sod to soil contact. After tilling, begin soil work to eliminate drainage problems and low areas in your lawn. Slope away from house, garage, etc. at a slope of no less than one inch in ten feet. Be sure to keep the soil level about one inch below sidewalks and the driveway.  Next add the organic amendments as needed based on your soil test results. After the slope has been maintained and the amendments added, lightly till the area again to a depth of 4 to 5 inches. Rake the soil smooth and remove all rocks, large soil clods, plant roots and sod chunks.
Order and Schedule Delivery:
Order your selected sod from a reputable local sod retailer and schedule delivery after all soil preparation is completed and you are ready to install. All sod should be planted the day of delivery. Quick installation is crucial to ensuring a healthy lawn. The longer grass sits on a pallet the more likely it is to die, or take longer to establish.
Installation:
Install sod immediately after it is delivered. Begin installing sod along a driveway or sidewalk, pushing edges together tightly without stretching. Use a sharp knife, spade or machete to trim edges of sod to fit the landscape. Be sure to stagger joints of the sod in a brick-like pattern to avoid continuous seams. Always place sod across steep slopes and stake in place if needed. Do not place small pieces of sod along outside edges. They will dry out and die. Begin watering sod within 30 minutes of installation. In hot weather, place unused sod in the shade and keep it moist until it is laid in the landscape. After a light watering, roll the sod with an empty roller to ensure good sod to soil contact.
Watering:
Water new sod as soon as possible after installation. Water at least once per day during the first two weeks after installation. Use enough water to keep the sod and soil moist but not soaking wet. Make sure the sod and upper soil area remain moist throughout the day. During hot, dry and windy weather. Sod can quickly dry out. Proper watering will ensure good turf rooting into the soil. As soon as the new grass is well rooted begin a deep and infrequent watering program to promote a deep and healthy root system.
Maintaining The New Lawn:
Until a new lawn has a fully established root system, avoid heavy use. Mow grass as soon as it starts growing. Make sure that you have a newly sharpened blade. Mow at the correct height for the grass (Kentucky blue grass should be mowed at a height of 2 ?to 3 inches). Remember to water deeply and infrequently, mow often with a sharpened mower removing no more than 1/3 of the grass blades at each mowing, and watch for insect, disease or fertility problems.
I hope I have helped. Have a Good Lawn!
Floyd McMahon