Building or adding a shed in your yard is a great way to organise your tools and get your yard straightened out. However, if you don't create the right base for it, your shed will quickly rot out from the moisture on the ground and you will have more of a mess than when you started. Here is a simple but sure way to build a base for a shed so it sits high and dry off the ground.
Dig out a base for your shed. You will need to dig down at least 6 inches. Square off the edges to keep it clean and neat looking. If you run a string from one side to the next, you will be able to see how deep you have gone in the middle. Dig out at least 6 inches more than the measurements of the shed.
Cut the 1x6 planks to fit along the side to hold the gravel in place. They should be placed perpendicular to the ground on the thin side. These will not only hold the gravel in place but it will also hold the dirt back from caving in along the sides.
Lay down the landscaping mat and cut it along the edges. This will be the base of your pit, holding the dirt back from mixing in with your gravel. Have the cloth run up the sides of the planks along the outside, stapling it in place to keep it from folding in on itself.
Pour the gravel into the prepared site. Use a metal garden rake to smooth out the stones as you add them to the site. By the time they are all added, you should have a level base to set your shed on.
Place the 4x4 timbers down on top of the gravel. Place them 12 inches apart the length or width of the shed. They will have minimal contact with moisture and will keep the shed high enough so that it has no contact with moisture. When it does rain, the gravel will absorb the water and let it drain into the soil through the landscaping mat.