How to Calculate Your Waste Factor
Natural stone installation requires masonry techniques such as cutting, splitting, sorting, and trimming stones to fit the desired finished area. The amount of stone cut and/or trimmed during the installation process is referred to as the “waste factor”. The amount of waste per job is dependent on the project requirements including how tight the finished joints are desired to be. Tighter joints require more trimming which generates more waste. A higher waste factor requires more stone to be consumed.
For example, lets say you are looking to cover an area that is 100 ft x 10 ft (1,000 SF). Based on your mock up, you are expecting a 30% waste factor. This means that you will need to purchase 1,300 SF (1,000 SF + (1,000 SF x 30%) ) of material in order to cover the desired area.
Performing the Calculations:
1.) Multiply wall height (step 1) X wall width (step 2): ____________ X ____________ = ____________ Total square feet of surface area
2.) Multiply height of all corners (step 3) X 75% coverage gained per lineal foot of corners: ____________ X 0.75 = ____________ Total suface area covered by corners
3.) Subtract the surface area covered by corners (step 2) from the total square feet of surface area (step 1): ____________ – ____________ = ____________ Total square feet of flats needed not including waste
4.) Add the expected waste to the total square footage of flats needed (step 3): ____________ + ____________ = ____________ Total square feet of flats needed