A gravel patio can extend your living space into the outdoors where your family and guests can spend time relaxing on sunny days. Gravel can give your patio a rustic ambiance and is relatively easy to maintain. One of the tricky aspects of building the gravel patio, however, is computing the amount of gravel is required to cover the space.
Gravel is sold by the ton, but computing for the cubic yard can be used as a starting point. The general formula requires that you first get the total area in square feet of the space that needs to be covered in gravel. This number is then divided by 12 in order to get the area with 1 cubic inch in volume. Multiply the result by the number of inches that you want for the gravel's thickness. This can go anywhere from 1 inch to 4 inches with the standard being 2 inches thick. To convert into cubic yard, divide the resulting value by 27. You can then round it off to the nearest whole number and use it as the estimate for the required tonnage of gravel.
Some online calculators provided by suppliers of construction materials would still multiply the resulting cubic yard by 1.5 in order for you to have some leeway on your project. Using the cubic yard outright or multiplying it by a number from 1 to 1.5 may depend on the following factors:
Area of the Patio
Deciding on the area of the patio can make a difference in how much extra gravel you need. A small, flat space will require less gravel and consequently, lesser risk of underestimating your needs. Conversely, a larger or slightly sloped area may require some extra gravel just so you would not run out of material in the middle of your project.
Design and Use of Other Materials
Since you are building your gravel patio from scratch, you may want to tap into your creativity and mix in other materials such as bricks or tiles along with the gravel. Bricks are often used for edging, so your patio space can be defined or set apart from the rest of your yard. However, these and other materials can also be used to create designs on your patio while filling the rest of the space with gravel. The more bricks or tiles you use, it would follow that the area that needs gravel would also reduce.
Since gravel is sold by weight, the wet or damp ones may have less gravel in a ton than dry gravel. The moisture content in the gravel can add to its weight so you may have to consider purchasing extra gravel to make up for the weight taken up by the water.
Other Important Variables
The thickness of the gravel layer and the amount of extra material you need are actually variables in computing for the number of tons you need for your gravel patio. You can play around with these numbers, increasing or decreasing them, so you can compute for the volume you need. If you have a compact sub-soil under the gravel, then an inch thick of gravel would probably suffice to achieve the look you want for your gravel patio.