Architectural Ornaments, Inc.

CAST STONE is a highly refined architectural precast building stone manufactured to simulate natural cut stone. One of the oldest known types of concrete, it is the most aesthetically refined form of concrete known today. Cast Stone is a masonry product which provides architectural trim, ornamentation or functional features to buildings and other structures

THE PLANNING PHASE
To assure the success of the project, the detailer (draftsperson) assigned to a Cast Stone job must have knowledge of architectural styles and designs as well as experience with the manufacturing techniques and the installation methods. The manufacturer details each piece with an aim toward simplification and standardization. As with any custom product, a great deal of economy is achieved by taking advantage of repetition. Shop drawings should be specified as needed - usually to show details and sizes of stones, arrangement of joints, relationship with adjacent materials and the location of each piece on the structure. Some builders and manufacturers, however, prefer to simply work with “shop tickets” which only show the part to be furnished; leaving jointery and fit up to the people in the field. Cast Stone can be formed in a greater variety of shapes than other types of natural cut stone. Lengths should be within 15 times the minimum profile thickness whenever possible. Consult your manufacturer if longer lengths are absolutely necessary. Longer lengths invite cracking and handling problems. Try to keep the back side flat and unexposed to view. Remember, most shapes are cast into a mould with four sides and a bottom. One side will always be unformed; typically the bottom of the stone. Never design a piece with a thin projection; one which has thickness less than twice the length of the projection. Weight is approximately 144 lbs. per cubic foot. To figure weights per lineal foot simply multiply cross section dimensions in inches. For instance, a window sill measuring 6" high x 10" deep = 60 lbs. per lineal foot.

THE MANUFACTURING STAGE
The two most widely used casting methods in use today are the “Vibrant Dry Tamp” (VDT) system and the “Wet Cast” method.. The VDT production system entails the vibratory ramming of earth-moist, zero-slump concrete against rigid formwork until it is densely compacted and ready for immediate removal from the form. This process enables as many as 100 pieces to be cast from a single mould in an eight hour day. It is ideally suited to fast-track construction projects because of its production capability and low formwork requirements. The VDT process guarantees total absence of bugholes and a grained finish which is almost impossible to distinguish from natural stone. The limitation of this process is that it generally requires one flat, unexposed side to the design as “L” shapes and similar shapes are more costly to produce. The wet cast process for manufacturing Cast Stone is similar to the manufacturing process used for making architectural precast concrete, but produces a finish which is almost impossible to distinguish from natural stone. Mix designs usually have coarse aggregate smaller than 1/2" and are comprised of an abundance of fines which, combined with careful hand and vibratory concrete placement techniques, leaves little or no voids after finishing of exposed surfaces. The wet cast process is more efficient as pieces become larger, less repetitive or impractical to demold immediately.