When you are planning to apply ground scrap wallboard on your building site, you should follow the steps listed below.
1. Determine the Application Rate
First, have the soil tested. You should have a routine soil test performed on soil where ground scrap wallboard will be applied. Your county Extension agent can supply you with bags for soil sample collection and detailed information on how to take a proper soil sample. A routine analysis will tell you the soil pH, and the amounts of phosphorus, calcium, potassium, magnesium, and zinc available for plants to use.
The application rate for the ground scrap wallboard is based on the amount of silt and clay that is typically present in the soil surface. Soils in the Piedmont, Mountains, and Ridge and Valley have more silt and clay than those in the Coastal Plain; consequently, higher rates of ground wallboard gypsum can be applied (Table 1).
Table 1. Recommended rates of ground scrap wallboard application.
Note. These weights are for dry ground wallboard.
| Region | Recommended rates |
|---|---|
| Piedmont, Mountains, and Ridge & Valley | 250 lb/1000 sq ft |
| Coastal Plains | 50 lb/1000 sq ft |
Research has shown that nutrient imbalances that are due to gypsum application do not generally develop in soils high in silt and clay. High rates of gypsum application can sometimes cause a problem with magnesium in sandy soils.
2. Determine if There is Enough Land at the Site to Apply All of the Wallboard
Calculate the actual amount of land needed:
- To determine if you have enough land available to apply wallboard for each project, multiply the number of square feet in the house by 1.5 lb.
- Divide this number by the appropriate number of pounds for your region in Table 1 and multiply by 1000 (see the calculation worksheet section below for assistance).
- This is the number of square feet you need to apply all of your ground wallboard.
- Then compare this number to the area you have for application (lawns, plant beds, and gardens). Be sure not to include the footprint of the house and impervious areas such as the driveway in your area for application.
Example:
- A 2,500-square-foot house is being built on a three-quarter acre lot (32,670 sq ft). Approximately 5,000 sq ft of the lot will be occupied by the house and impervious areas.
- This means 27,670 sq ft of land is available for ground scrap wallboard application.
- Using 1.5 lb per square foot, construction will generate about 3,750 lb of wallboard. Using a typical application rate (Table 1) of 250 lb/1000 sq ft, you will need 15,000 sq ft of land for application.
- Because 27,670 sq ft is available for application, all of the scrap wallboard generated can be land-applied.
Proceed with the following steps if you have enough land to apply the wallboard from a specific site.
3. Segregate Scrap Wallboard
Place all the clean, scrap wallboard in one location that will be accessible to the grinder. Moisture-resistant or fire-retardant wallboard should not be used because guidelines for land application of these products are not available at this time. Wallboard from demolition or that has been painted or wallpapered should not be used.
4. Grind the Wallboard Scraps
Clean wallboard scraps should be ground with equipment that has a 2-in. screen to make sure the paper is shredded and there are no large chunks of wallboard. Controlling dust during grinding is important. If ground wallboard will be stored before application, cover the pile with a tarp to keep the material dry and easy to handle.
5. Apply the Ground Wallboard
Apply fertilizer and high-magnesium dolomitic lime to the soil according to the recommendations from your soil test results. The ground wallboard should be evenly spread over the soil at or less than the recommended rate.
The images in Figure 1 illustrate an even application at the recommended rates. The ground wallboard should tilled or mixed into 4 to 12 in. of soil.
Beneficial reuse does not include digging holes and burying the wallboard.
calculation worksheet
To calculate the amount of land needed to apply ground wallboard from a building site:
Step 1: Determine the area needed to apply wallboard. Formula:
[Size of the house (ft2) x 1.5 lb/ft2] ÷ [Recommended application rate (lb/ft2) from Table 1] x 1000
Your Numbers:
( _____ ft2 x 1.5 lb/ft2) ÷ _____ lb/ft2 x 1000 = _____ ft2
Step 2: Calculate the existing area available to apply wallboard. Formula: Size of the lot (ft2) – size of impervious area (ft2; driveways, etc.)
Your Numbers:
_____ ft2 – _____ ft2 = _____ ft2 available to spread wallboard
Step 3: Compare the figures. The number in Step 1 is the amount of area needed to apply ground wallboard from a site. If the number calculated in Step 1 is less than the number from Step 2, you have enough land to apply all of the ground wallboard from your building site.
Useful Facts
- A skid loader bucket will hold about 1 cubic yard.
- A front end loader will hold 2–3 cubic yards.
- Dry ground scrap wallboard weighs about 400 lb/cubic yard.
- At a rate of 250 lb/1000 sq ft, one skid loader bucket would cover 1,600 sq ft (an area of 40 ft x 40 ft). This is an area slightly smaller than a volleyball court.
- At a rate of 250 lb/1000 sq ft, about one-third of a skid loader bucket would cover the goal box on a soccer field.
This resource is provided by the UGA College of Agricultural and Environmental Sciences, Cooperative Extension, and the Engineering Outreach Service, with the support of the Pollution Prevention Assistance Division. The original manuscript was written by Julia Gaskin, Extension specialist-Land Application; Clint Waltz, Extension specialist-Turfgrass; William Miller, professor, Crop & Soil Sciences; Melvin Garber, former Extension horticulturist-Ornamentals; Timothy Smalley, associate professor, Horticulture; and Gary Wade, Extension coordinator-Horticulture.
