Sack-Rubbed Finish

A sack-rubbed finish is sometimes necessary when the appearance of formed concrete falls considerably below expectations. Perform this treatment after completing all required patching and correction of major imperfections. Thoroughly wet the surfaces and commence sack rubbing immediately.

The mortar used consists of one part cement; two parts, by volume, of sand passing a No. 16 screen; and enough water so that the consistency of the mortar will be that of thick cream. It may be necessary to blend the cement with white cement to obtain a color matching that of the surrounding concrete surface. Rub the mortar thoroughly over the area with clean burlap or a sponge rubber float, so that it fills all pits. While the mortar in the pits is still plastic, ruab the surface over with a dry mix of the same material. This removes all excess plastic material and places enough dry material in the pits to stiffen and solidify the mortar. The filings will then be flush with the surface. No material should remain on the surface above the pits. Curing of the surface is then continued.