As Sprucey says ---- Clean rock usually sold at home centers is not for regrading. Clean rock allows water to percolate through which defeats the purpose of grading away.
Originally Posted by bculp
Top soil is generally not recommended since it is a loose soil which will allow water to drain through --- it is better than clean rock. Besides, it would be a waste of top soil under a deck and would create a nice fertile haven for weed growth. If anything, if you are paying the extra price for topsoil used in grading then use it for planting beds or a lawn.
Soil that's called "fill"which will have less organic material and depending more clay. This type of soil doesn't allow the water to drain through readily which allows it to flow down the sloping needed.
Crusher run or 1/4 down is ideal for gradeing issues. The stone dust compacts when wet allowing the water to flow nicely.
If the ground under the deck is sloping toward the foundation , this is referred to as a negative slope. All you need to do is shovel as much 1/4 down material as need to provide a slope that runs away from the foundation ( known as a positive slope ). As Sprucey mentioned -- you only need a minimum of 1/4 inch per foot of positve slope away from the foundation to effectively keep water flowing toward the foundation.
But with the regrading, how is it actually done? We dig and remove dirt or we dig and like hoe the slope down? So what is the actual process/steps to the regrading?
Depending on your site conditions you may only need to grade about four feet from the foundation outward.
Take a four foot level and lay it on the ground --- you'll see it likely tilts toward the foudation. Raise the level until until "level" --- measure the distance from the bottom of the level to the ground --- add an inch --- that will indicate how much to buildup around the foundation. Then gradually work away from the foundation and rake the fill sloping away .
"" an ounce of perception -- a pound of obscure "