One of the most important, if not the most important, aspects of operating a profitable business is knowing what to charge. Many factors go into properly estimating a project such as: Labor Costs, Material Costs, Equipment Costs, Trucking Costs, and more. In this article we will discuss how to properly calculate how much material will be needed for your sealcoating jobs.
The most important number you will need to know for this calculation is 231. Not only is that how many mini marshmallows I can fit in my mouth, that is also the number of cubic inches per gallon. This is vital for sealcoat, crackseal, striping and any other product that uses material purchased by the gallon.
Cubic Inches per Gallon = 231
Now all we need to do is figure out how many cubic inches there are in your job. That is where the second important number comes from: 1,728. Yes, this is how many cubic inches are in a square foot, but more importantly it is how many pushups I can do in a row. (JK… I look like Jack Skellington).
Cubic Inches in a Cubic Foot = 1,728
I’m assuming you are measuring your jobs by the linear foot. If that is the case, this becomes really easy to calculate:
Let’s assume you’re doing parking lot with 1,000 linear feet of cracks.
The next thing we need to determine is the average crack depth and width.
For this exercise we will assume an average crack width of 1 inch and a depth of 1/2 inch (.5).
To be really accurate we need to know how wide the tip is on your kettle wand or the foot on your walk-behind crackseal cart. We will assume a 4″ overback (the streak above the crack) at a thickness of 20 mils.
Average Crack Width = 1 inch
Average Crack Depth = .5 inch
Overband Width = 4 inches
Overband Thickness = 20 Mils or .02 inches
Now we have all the info we need to accurately estimate the amount of material. If you wanted to leave off the overband that is ok, but you’d want to add a bit extra material to the output.
Crack Width * Crack Depth * 12 = Cubic Inches of crack needed per linear foot of crack
Overband Width * Overband Thickness in Inches * 12 = Cubic Inches of Overband per linear foot of crack
If you add those two numbers together you get the total cubic inches of material needed per linear foot of crack
Example:
Gallons?! Crackseal is purchased in blocks you bloke! I know. I know. Most manufacturers will have Pounds per Gallon and Pounds per Block listed on their spec sheets. For example, check out this Crafco Roadsaver 201 spec sheet: https://crafco.com/pds/34201-Crafco-RoadSaver-201-Product-Data-Sheet.pdf
This shows 9.7 pounds per gallon and blocks are sold in 30 pound blocks. This means that 30 / 9.7 = 3.09 Gallons per block (Walaa!)
So this means if we need 30 Gallons of material and each block contains 3.09 Gallons, then we will need 30 / 3.09 = 9.7 (10) blocks of material!
Once you have figured this out once then you know that 1,000 linear feet / ~10 blocks needed = 100 linear feet per block. Now you have an easy reference to know how many linear feet at that crack depth and width is covered by a single block of material. Obviously if the crack depth changes to 1 inch that will significantly change your coverage rate. (SPOILER: it almost cuts it in half… ~55 Linear Feet per block)
Once you have the initial calculation to figure out your coverage rate per linear foot, it become very easy to then calculate material needs going forward. You can create a quick reference sheet that shows different crack depths / widths and their coverage per block. This would allow very fast material usage and estimating.
The good news is that you do not need to remember all this or even do it yourself. Let Bitumio handle all of this and accurately calculate material needs, coverage rates, etc. for you every time from anywhere to create estimates accurately every time.
