Shrinkage of a sealant, after application in a building joint, is caused by loss of volatile components from the sealant. This loss results in a decrease in volume and, hence, a change in the sealant's shape. This change in shape, in some applications, should be taken into consideration for acceptable joint appearance and geometry.

The shrinkage value obtained by this test method helps predict the appearance and geometry of the cured sealant in a building joint and is helpful in determining the amount and type of tooling to be done during installation of the sealant.

Latex sealants cure primarily through water evaporation. They may also contain small amounts of other volatile components. However, in this test method all volatiles are treated as water. This assumption still provides a meaningful shrinkage value since the small quantities of other volatiles and their differences in density from that of water do not significantly affect the usefulness of the result obtained.