How to Calculate Lbs Per Square Foot

Contributor

By Josh Weber
eHow Contributing Writer

If you are considering adding large and unusually heavy appliances or pieces of furniture to your home, a basic understanding of weight-to-space ratios can become critical in deciding where to place these pieces. While most homes today are engineered to support weights of 50 to 60 pounds per square foot, many of today's appliances and furniture come close to exceeding this weight limit. Armed with a basic knowledge of the weight of the object you are locating in your home, you can quickly calculate the load addition for any room of your home.

Difficulty: Easy

Instructions

Things You'll Need:

Measuring tape
Calculator

Step 1

Using a tape measure, find and record the length and width in inches of the object for which the pounds-per-square-foot calculation is being made. You can then calculate the number of square inches by multiplying the length measurement by the width measurement.
Step 2

Divide the number of square inches calculated above by 144 inches per square foot to convert square inches to square feet.
Step 3

Determine the weight in pounds of the object for which the calculation is being made. If the weight is not available in the specifications for the object you will need to weigh and record the weight.
Step 4

Divide the object weight in pounds by the the number of square feet in the object to obtain the pounds per square foot of the object.

Tips & Warnings

When calculating displaced weight per square foot you will need to consider the weight of the appliance or furniture when fully loaded. For example, a bathtub filled with 50 gallons of water will carry 400 pounds of added water weight. A waterbed with a capacity of 350 gallons of water will increase its weight by 2900 pounds.
In considering the load weight your floors may tolerate, you must consider the age and condition of the floor joists and whether any modifications affecting joist integrity (such as plumbing or HVAC modifications) have occurred over the years.