Rough Cast Finish

A rough cast finish can be obtained by using trowels covered with carpet or burlap. To obtain the best results a slight excess of sand is used and the plaster mixed so as not to be too wet.

Slap-Dash Finish

Slap-dash finish can be secured by throwing on the final coat with a wood paddle. This requires some little practice, but after the knack is acquired a very attractive surface can be produced in this manner.

Pebble-Dash Finish

A pebble-dash finish may be obtained by throwing clean pebbles into the fresh stucco of the final coat before it has commenced to harden. Pebbles should be uniformly about 1/2 inch in greatest dimension, round, and of good color. They should be washed thoroughly clean and be wet when thrown against the mortar. If the color of the pebbles is not to be exposed, then they may be wet with a cement and water paint immediately before thrown against the surface. They are then more certain to adhere firmly to the stucco.

Stucco should not be allowed to dry out rapidly after applied. If the surface is one where it will be exposed to the sun, then some kind of covering must be hung over it or it must be kept wet down by frequent sprinkling during the first few days. Protection must also be given against freezing, for at least 48 hours.

The quantity of cement required to cover a given area with stucco finish depends largely upon the total thickness of the coat to be applied, but assuming three coats, each 1/2 inch thick and that the mixture is proportioned as previously recommended, a batch of stucco in which 1 sack of cement is used will cover about 17 square feet.

Patching Imperfections

Sometimes it is necessary to do considerable patching on a concrete surface just because proper care was not taken when placing the concrete. If the object is small it is far more satisfactory to do the work over than to attempt patching it up, but where a considerable volume of materials has been used and remaking the object would be unnecessarily expensive, a certain amount of satisfactory patching may be done if proper methods are used. In all cases the surface to be repaired or patched must first be thoroughly cleaned of all loose material and the clean sand and broken aggregate surfaces exposed to receive the patching material. After cleaning, the surface to be repaired must be saturated with water so thoroughly that the old concrete will not absorb water from the new mortar or concrete to be used in the patch. Care should be taken not to have thin edges on patches. To avoid this it may be necessary to cut out sound concrete around the place to be patched so as to give deep edges to the patch. If possible, the edges should be slightly undercut. In order that the patch, when finally hardened, will have the same color as that of the surface to which applied, the patching mixture should be of the same proportions as the concrete used in the object being prepared. For instance, if the concrete object was cast of a 1:2:4 concrete, then a 1:2:4 concrete should be used for patching, or a 1:2 cement-sand mortar. In this way the surface of the patch will have the same color as the surface in which it was placed. When hardened, the repair can be hidden quite effectually by carefully rubbing the surface with carborundum stone and water, as described elsewhere.

A concrete swimming pool for the ducks.