1.1 ,This test method describes an in situ method for determining the deformation properties of existing unreinforced solid-unit masonry. (See Note 1.) This test method concerns the measurement of in-situ masonry deformability properties in existing masonry by use of thin, bladder-like flatjack devices that are installed in cut mortar joints in the masonry wall. This test method provides a relatively non-destructive means of determining masonry properties.