Standards applicable to cmu contain three classifications of weight, expressed in pounds per cubic foot: normalweight, mediumweight, and lightweight.
Normalweight is 125 lbs./cu. ft. and over. Units stocked in normalweight include Slumpstone™ units and fence units (stucco block, Catalina, Balboa, etc.). Certain colors are stocked only in normalweight - all Slumpstone™ colors, and precision colors such as Colorcrete (pink), Fawn, Mission Tan, and #500 (yellow).
Mediumweight is less than 125 to 105 lbs./cu.ft. "Structural" types and sizes are stocked most extensively in mediumweight. In addition to precision and split face gray, a scored split and standard color are normally available.
Lightweight is less than 105 lbs./cu. ft. Normally stocked in selected sizes in gray.
Of the three weights, normalweight is the least expensive and lightweight is the most expensive. Mediumweight is most popular (and therefore has greatest availability) for structural applications as its moderate weight and cost generally offer the best labor production to material cost ratio. For example weights per units and wall area, please see charts in Technical Articles, Average Weights.