Polystick XFR self-adhering modified bitumen single ply waterproofing underlayment
This is a listed roofing assembly. Listing 8180-2305:0503. This site cites ASTM E108 / UL 790. Match the model and orientation.
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The 2026 capture of BML listing 8180-2305:0503 lists four Class A Polystick XFR roof systems with different ply counts.
The description for 8180-2305:0503, captured on 5 September 2026, identifies four Class A systems. Their differences matter more than the product name's “single ply” wording when selecting an assembly. Each prints Unlimited incline.
For the NC deck system, any UL Classified polyisocyanurate insulation of any thickness accompanies one self-adhered XFR base ply. Surfacing is UL Listed or Classified copper panels, UL Listed or Classified steel standing-seam panels, or shingles. The captured BML description prints “26 gauge minimum” after each copper/steel/shingle surfacing list. The copper/steel/shingle system on C-15/32 or spaced sheathing instead identifies one self-adhered XFR underlayment ply. On that same printed deck description, the aluminum system requires two self-adhered XFR underlayment plies and mechanically fastened UL Classified aluminum panels at least 0.032 inches thick.
Those copper/steel and aluminum C-deck systems share optional layers. A base sheet may be a minimum single ply of Type 15 or Type 30 asphalt-saturated felt, or Type G1 or G2 asphalt-saturated glass mat, mechanically fastened. Optional insulation is UL Classified polyisocyanurate, perlite, wood fiber or polyisocyanurate/perlite board, any thickness, mechanically fastened or attached with UL Classified insulation adhesive. An optional ply sheet uses the same minimum felt or mat types, or self-adhered XFR.
The tile system also names C-15/32 or spaced sheathing, but allows one or more self-adhered XFR plies. Its optional mechanically fastened base permits those minimum felt or mat types, or PolyAnchor HV or Elastobase V. Clay tile must comply with ASTM C1167, be Grade 1, Type I or II, and weigh at least 580 pounds per 100 square feet installed. Concrete tile instead requires ASTM C1492 and at least 903 pounds per 100 square feet installed. Follow the tile manufacturer's installation instructions.
The 2025 handbook printed three systems and named UL 790; the later captured description does not name that protocol. The different captured descriptions establish neither cancellation nor equivalence. Before specifying a surface and ply count, confirm the current GOVmotus description and exact proposed assembly. Use the listee's data sheet and UL Roofing Systems Directories for product details and operational considerations.