Anyone have a solid resource for detailing PMMA liquid flashings with pedestal paver systems to maximize walkable area without jeopardizing warranty? I’m pairing 60 mil PVC, 1/2 inch gypsum-fiber cover board over two layers of 2.6 inch polyiso, targeting FM 1–90 and 1/4 inch per foot taper, and I’m concerned about compressive creep at pedestals and around RTU curbs. Manufacturer bulletins or detail sheets you trust for isolators, penetration sleeves, and heat-weld transitions would be appreciated?
I’d spec 12x12 HD “crush plates” (1/2 in gypsum‑fiber or 3/8 in cement board) set in low‑rise foam under each pedestal — think “high heels need a dance floor” — plus a protection mat/slip sheet over the PVC to keep iso creep in check. For PMMA at curbs and pedestals, don’t bond to PVC; heat‑weld a 6 in fleece‑backed PVC strip and tie the PMMA into the fleece per the detail in Soprema’s ALSAN RS guide: https://soprema.us/resources/alsan-rs-detail-guide/. If your layout is tight, doubling the cover board just in the paver zones is cheap insurance; what pedestal brand are you using?