Page 479 - Construction Waterproofing Handbook

ENVELOPE TESTING 12.19

FIGURE 12.17 Job-site testing of curtain wall and precast units. (Courtesy of Architectural
Testing, Inc.)

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1 in . This rather small test area requires the MAT test to be repeated in numerous loca-
tions on the masonry wall. Included in the testing should be specific areas of mortar
joints, including the top, middle, and bottom of head joints and bed joints, as shown in
Fig. 12.19. Test results should be plotted against time and joint location, and summarized
for review.
Again, there are no standard results pinpointing excessive moisture absorption using a
MAT test. However, if a joint absorbs 5 mL of water in less than 5 minutes, that is con-
tributing to leakage that might exceed the divertor system’s capability. Measurements
exceeding absorption of 5 mL in 5 minutes necessitate a review of corrective measures to
be taken to repair the mortar joints, including those described in Chap. 8.

SEALANT JOINT MOVEMENT

If an envelope is experiencing sealant joint failures, it may be necessary to measure the
movement occurring at the joint to determine if it exceeds the capability of the sealant
material. Sealant manufacturers can provide a relatively simple device to accurately mea-
sure joint movement, as shown in Fig. 12.20.
The joint movement indicator base (with an adjustable setscrew) is firmly attached to one
side of the joint, and the opposite side receives a scribe plate. The setscrew will etch a record
of joint movement onto the scribe plate, (Fig. 12.21). Typically the movement indicator is left
in place for a sufficient period of time, an entire weather season, to record both expansion
and contraction movement and thus provide a total amount of joint movement occurring.