Application Rates: How Much Deicing Product Do I Need?

If you still need salt once the pavement has been cleared, use it sparingly.  

Spot treat small icy areas

For areas that are mostly clear after removing the snow, such as a few sidewalk squares, front steps, or isolated icy spots near a door or parking entrance/exit, treat only the slick patches that remain after shoveling and scraping. Do not spread salt over the entire cleared surface ‘just in case.’ Scattered grains placed directly on the ice are usually enough to start melting and break the bond with the pavement. Give the salt time to work, then scrape or sweep away loosened slush and ice. If traction is needed right away, consider using sand or grit instead of adding more salt. 

Treat entrance areas and small areas with granular salt by hand or with small equipment

For small areas, apply about 1 pound of salt per 250 square feet after clearing the snow and patches of snow or ice remain. This is equivalent to about a 12-oz coffee cup (about 1 lb.) of salt scattered upon 10 sidewalk squares or a small 20 foot long by 12-foot-wide driveway. Use no more than 4 pounds of salt per 1,000 square feet. If you are using a blend containing calcium or magnesium chloride you may be able to use even less. These chemicals absorb moisture from the air to jump start the melting process and help the deicer stick to the pavement. If you have a lot of ice on the pavement, more salt may be needed. Adjust rate between 1 to 4 pounds depending on the amount of snow or ice remaining on the surface after clearing.

At these rates, granular salt crystals should be spaced about 2 to 3 inches apart. You should see space between the grains, not a layer of salt. Melting will start and move out from the salt granule up to a few inches depending upon the size of the granule. Pavement does not need to be completely bare; there only needs to be enough bare pavement to provide traction under a foot or tire.

Give the salt time to work, especially in cold weather. Adding more salt will not speed up melting. 

Treating parking lots and sidewalks

Application rate charts should be used to determine how much material to use, especially for larger areas. There are many versions of application rate charts created by different agencies, non-profits, and businesses.

Application rate charts usually have several things in common:

• They assume the area is cleared before deicers are applied
• They are based on pavement temperatures
• They consider temperature/weather trends
• Rates differ based on type of deicer used
• Separate rates are provided for liquids vs. granular materials
• For parking lots and sidewalks, rates are often based on lbs./1000 square feet, but may be based on lbs./lane mile or lbs./acre
• Some consider how soon a second treatment can be applied if needed (cycle time)
• Some include ranges of rates 

Also consider these factors when choosing application rate:

Develop your own application rate chart by adjusting your current rates incrementally downward toward the following MPCA guidelines or other accepted rates. Where temperature categories overlap, select the rate most applicable to your situation. 

Wisconsin Salt Wise developed a Product Application Calculator that provides application rates by entering the type of deicer and the pavement temperature. This site also includes application rate guidelines and much more information.

The MPCA Deicing Application Rate Guidelines for Parking Lots and Sidewalks manual provides guidance on suitable options for liquid and dry applications and encourages lower application rates. A Deicer Fact Sheet with information on application rates and the Minnesota application rate guidelines is a handy two-page document to keep in a plow truck or other vehicle used for applying deicers. These application rate guidelines are for pavement that has been well-cleared of snow. The MPCA chart also includes application rates for sand in cold weather or for freezing rain. If bare pavement is not needed, sand can be used at lower rates above 25°.

Deicing Application Rate Chart

These rates are based on road application guidelines (LRRB 2022). Use them as a target to achieve by gradually adjusting your application rates downward. Application rates are based on thoroughly cleared surfaces.

Instructions for using application rate table for calibrated spreaders

1. Use Deicing Application Rate Guidelines for parking Lots and Sidewalks. Selecting the row with the appropriate pavement temperature, temperature trend, and weather conditions.
2. Select the column (1-4) that has the type of material used.
3. Find the box where the row (A-P) and columns (1-4) intersect to find the application rate.
4. Compare those values to the calibration chart you created for your spreader.
5. Select the correct spreader setting.

Example:

1. Parking lot is 54,000 square feet
2. Temperature is 22° and falling. It has stopped snowing.
3. Using salt pretreated with salt brine (1)
4. Find the 20 - 25° ↓ box (J). Follow it to the right to the column labeled “Salt Pre-wetted/pretreated with salt brine (1).” Read the rate in the box. The box where the column and row intersect shows a rate of 2.0 lbs./1,000 square feet.
5. Refer to the calibration chart in the vehicle and set the spreader to the setting that most closely matches the 2.0 lbs./1,000 square feet.
6. You are ready to apply.

Instructions for using application rate table for spreaders that are NOT calibrated

Using the example above:

1. Calculate size factor: Divide the parking lot size (54,000 sq. ft.) by 1,000 sq. ft. 54,000/1000 = 54. The size factor is 54.
2. Find application rate (2.0).
3. Multiply application rate by size factor, 2 x 54 = 108.
4. The amount needed for the entire lot is 108 lbs. pre-wetted/pretreated salt.
5. Because the spreader is not calibrated, the setting is unknown.
6. Although the calibration setting is not known, this establishes the amount of salt to use.
7. Determine the best method to spread the 108 lbs. across the parking lot.

Instructions for using Deicing Application Rate table. (MPCA 2022)