Since 1962, architect Paul Rudolph of New Haven Connecticut, has been developing a technique for building in concrete which demonstrates a new means for achieving a beautiful concrete finish. Rudolph's method involves the preparation of finned forms. On a plywood backing, trapezoidal fins 2 inches deep by 1 and one-half inches at the base by one-half of an inch at the top are nailed in place. They form a regular pattern, the space between the fins being equal to the width of the fins.
These forms are paced as usual for any concrete wall. A stiff mixture of concrete with about a 2 inch slump and 1 to 1 and one-half inch aggregate is then placed. After removal of the forms, the fins are broken off with a hammer, thus exposing the aggregate. Often the aggregate breaks along with the concrete, and the interior tones of the aggregate are exposed.
This method does more than decorate an otherwise smooth surface. Often used both inside and outside, it eliminate the necessity of any further finishing of the concrete.