Mechanically Attached Single-Ply Fastener and Plate Takeoff

On such a system the fasteners go through the SIDE LAP and the next sheet welds over them, so the fastener rows ARE the seams -- and the rows land on the USABLE width after the lap, not the nominal roll width, which is the undercount to avoid. An 8,000 sq ft roof on 10 ft sheets with a 6 in lap has 842 LF of seam; at 12 in on center in the field and 6 in in the perimeter and corner zones over a quarter of that length, 1,054 fasteners and plates, 1,107 with waste, about 13.8 per square. Cover tape is counted only when fasteners land in the FIELD of a sheet instead of a welded lap. The spacings are NOT built in -- on-center spacing and the zone widths come from the wind-uplift calculation and the assembly's FM or UL approval, so they are inputs. A takeoff, not an uplift design.

usable width = roll width - side lap; seam length = area / usable width (delegated to membrane-roof-takeoff); perimeter seam = seam x share; field seam = seam - perimeter; fasteners = ceil(length x 12 / on-center spacing) for each zone; total = ceil(sum x (1 + waste)); plates = fasteners; cover tape = ceil(seam x (1 + waste)) only when fasteners land in the field of a sheet; density = fasteners / (area / 100).

Mechanically attached single-ply geometry. The rows follow the seams because the fasteners pass through the side lap and the succeeding sheet is welded over them. Spacings and zone extents are project values from the wind-uplift calculation and the assembly approval, not from this tile.

The geometry is arithmetic. No FM Approvals or UL assembly table, and no manufacturer spacing chart, is reproduced here - none is used, because every spacing is an input.

Estimate. AHJ and licensed professional govern.

Field names used by the API: roof_area_sf, roll_width_ft, sidelap_in, field_spacing_in, perimeter_spacing_in, perimeter_fraction_pct, field_seam_covered, waste_pct, usable_w_ft, seam_lf, field_fasteners, perimeter_fasteners, base_fasteners, total_fasteners, plates, cover_tape_lf, fasteners_per_square

• Rows follow the seams fasteners pass through the side lap and are welded overmechanically attached single-ply practice
• Usable width roll width minus side lap, delegated to membrane-roof-takeofflanded sibling tile
• Spacings field and perimeter on-center spacing are INPUTS from the uplift design and the approvalstated scope limit
• Zone share perimeter and corner share of seam length entered by the user, not derivedstated scope limit
• Plates one per fastenerassembly practice
• Cover tape counted only for fasteners in the field of a sheet, zero when all are in welded lapsassembly practice