b'TECHNICAL & RESEARCHFigure 8. Properly placed and attached insulation plates and fasteners.Figure 7. Adhered polyvinyl chloride system over properly installed foam adhered insulation and cover board with minimal visual evidence of cover board edges or corners.to comply with FM 1-90 attachment criteria according to FM Globals data sheet 1-28. 2AnotherFigure 9. The dotted blue line indicates the article in this series will explain how wind-uplift testing can be used to determine whether thosejoint between two insulation boards under criteria have been met. adhered thermoplastic olefin membrane. On projects where my firm is the designer of record, we regularly recommend that the low-riseRed arrows indicate where insulation plates foam-adhered boards be temporarily ballasted using pails filled with adhesive, cinder blocks, orare installed spanning across the joint of two other portable ballast available on jobsites, such as buckets partially filled with concrete, old tool- insulation boards, the fastener is installed boxes filled with concrete, or bucket or boxes of fasteners or attachment plates. Temporary ballastbetween the boards.is meant to provide uniform compression of the foam adhesive beads, spreading the foam beads out and ensuring that the top board remains in contact with the foam adhesive and substrate while the adhe-sive is curing. Figure 7 presents an example of installed results when the adhered insulation and coverboard are temporarily ballasted while the foam adhesive is curing. There is minimal visual evidence of raised, curled, or cupped roof boards. The red arrows indicate the locations of joints between cover boards below the membrane.When mechanically attached roof insulation is spec-ified or required by the designer of record for projects wherehailwarrantiesarenotrequired,thereisalso ariskthatnonstandardornoncompliantinstallation techniquesmaybeused.Fasteningpatternsmustbe established or specified to meet building code and FM requirements, as well as the roof manufacturers warranty prerequisites.Common defects found and issues to identify include the following (refer to Fig. 8 and 9):Insulation fasteners spanning between two boards. Each fastener and plate must be wholly installed onto one board.Use of the wrong fastener plates (that is, seam plates in lieu of insulation plates).Fasteners installed into the low flute (trough) of the metal deck. Roof system manufacturers and FM require that fasteners penetrate the top flute of the metal deck for maximum pull-out resis-tance. Fasteners installed through the lower fluteFigure 10. Loading and staging area on the roof.38www.mrca.orgMidwest Roofer 9'