Fence post hole soil weight considerations can be valuable when selecting the right equipment for the job and in making a job safer.
Fence Post Hole Soil Weight Considerations
by Titus Nelson, PE
Inventor of the Holey-Moley Digger
Fence post hole soil weight considerations are important especially when the weight of different soil types can vary by as much as 100%. These weights can vary from 10 lbs/gal for dry, loose dirt to over 21 lbs/gal for limestone. Water can boost the weight of dry sand an additional 3 lbs/gal. Consideration of soil type and moisture content should be an important factor when purchasing, digging tools, wheelbarrows or shop vacuums to make the task of moving soil safer and easier. The following chart provides the weights of different soil types per cubic foot when shopping for wheelbarrows, and per gallon for sizing shop vacuums.
Some Rules of Thumb
- First of all, a 6-inch diameter hole yields about 2 gallons of soil per foot of depth.
- Thirty pounds, the weight of approximately 2 gallons of wet sand, is therefore about the maximum weight a person should lift in a 5-gallon pail.
- Especially relevant is thirty pounds is about how much you would put into a standard sandbag.
- Most noteworthy is Shop-Vacs can lift up to 1-pound of sand/gravel a second
- 10 gallons of dry soil weighs about 100 pounds
Soil weight adds up fast
Shop vacuums can lift as much as a pound of soil/second and can fill a 10-gallon tank in several minutes. Within that short timeframe, the shop vacuum will weigh over 100 pounds. Consequently this weight will be a bit cumbersome to move, so large wheels and a good handle are important.
Dealing with wet soils
Many shop vacuums today are made for wet/dry operation and can easily handle wet soils. When damp clay soils become a bit messy a shop vacuum made for wet/dry applications makes cleaning up with a hose very easy. For wet soil work a wet/dry vacuum is probably one of your best investments.
Hole Volume Calculator
The Holey-Moley Digger web site has a Hole Volume Calculator for Round Holes. The data table above is conveniently in a drop down menu. The calculator output also includes the volume of dirt removed. Therefore the calculator takes into consideration the swell factor after the soil is removed from a hole. Try it out here to see how much soil will be removed from a hole using a Holey-Moley Fence Post Hole Digger. Use 2.25 inches for the hole radius input and use any hole depth desired in inches. See the Soil Caculars page here.