‹‹‹ Vitr. 2.4.1 | Table of Contents | Vitr. 2.4.3 ›››
2If there be no sand-pits where it can be dug, river sand or sifted gravel must be used. Even sea sand may be had recourse to, but it dries very slowly; and walls wherein it is used must not be much loaded, unless carried up in small portions at a time. It is not, however, fit for those walls that are to receive vaulting. In plastered walls, built with sea sand, the salt which exudes destroys the plaster;
2But if there are no sandpits from which it can be dug, then we must sift it out from river beds or from gravel or even from the sea beach. This kind, however, has these defects when used in masonry: it dries slowly; the wall cannot be built up without interruption but from time to time there must be pauses in the work; and such a wall cannot carry vaultings. Furthermore, when sea-sand is used in walls and these are coated with stucco, a salty efflorescence is given out which spoils the surface.