© Infrastructure Health & Safety Association (IHSA)
41 • Institute for Work & Health (IWH)
Calculating Load Weights Using Area (Use Table 1.3 in M035)
When weights are based on area and a standard size or gauge:
• Weight = area × unit weight in lbs/ft
2
• Calculate the area in ft
2
• Convert the area to weight
When weights are based on area and thickness in inches:
• Weight = area × thickness in inches × weight in lbs/ft
2
• Calculate the area in ft
2
• Convert the area to weight
Example 1:
Calculate the weight of a solid 2" gypsum-sand plaster partition with the following
dimensions.
Step 1: Calculate the area.
Area = L × W = 8 ft × 4 ft = 32 ft
2
Step 2: Locate the unit weight in Table 1.3 Weights of Materials (Based on Surface
Area).
Solid 2" gypsum-sand plaster = 20 lbs/ft
2
Step 3: Calculate the weight.
Weight = area × unit weight/ft
2
= 32 ft
2
× 20 lbs/ft
2
= 640 lbs
