Pillows, Mortar & Composite Sheet
Big openings need different tools. Cable trays, bus duct, banks of conduit, oversized sleeves and blank openings are beyond what a bead of sealant can protect — this is pillow, mortar and board territory, with UL Classified systems up to 3 hours.
Firestop pillows are the re-enterable choice: stack them in the opening around cable trays, and when cables change, pull them out and put them back — no demolition, no re-caulking. FRM fire-rated mortar is the permanent choice for large floor openings: one 45 lb bag mixes with water to a cubic foot of lightweight, load-bearing fill. Composite sheet covers wide wall openings — a 36×36 rigid board that cuts with standard tools and combines with sealant for mixed penetrations.
All three ship same-day from New Jersey at distributor pricing. Not sure which system your opening needs? Send a photo and dimensions to sales@firestop-usa.com and we will spec it with the UL documentation.
Which one do I need?
Pillows, Mortar & Composite Sheet — the lineup
Metacaulk® Firestop PillowsUnique combination of highly intumescent graphite material mixed with mineral fibre blend in a durable PVC bag.View product, specs & TDS →
Metacaulk® FRM Fire-Rated MortarSpecially formulated rapid-hardening gypsum/cement compound.View product, specs & TDS →
Metacaulk® Composite SheetRigid fire-resistive panel with reinforced intumescent material bonded to non-magnetic #304 stainless steel sheet.View product, specs & TDS →Pillows, Mortar & Composite Sheet — frequently asked
What is the best way to firestop a cable tray?
Through a rated wall, firestop pillows are the standard: UL Classified, stacked around and between cables, and fully re-enterable when circuits are added. For permanent floor penetrations, FRM mortar or composite sheet systems apply. We will match the UL system to your tray size and fill.
How much firestop mortar do I need?
One 45 lb bag of FRM yields about 1 cubic foot mixed. Measure opening length × width × required depth (per the UL system, commonly 4") and divide — or send us the opening schedule and we will do the takeoff.
Are firestop pillows reusable?
Yes — that is their purpose. Pull them to add or remove cables, then re-stack per the listing. No sealant to cut out, no system to rebuild, and inspection-friendly.
Need the right UL system?
Send your penetration schedule or a photo — we match the UL Classified system, provide submittal documentation free, and ship same-day from New Jersey at distributor pricing.
More firestop categories: Firestop Sealants · Putty Pads & Electrical Box Protection · Pipe Collars, Wrap Strips & Sleeves · Cast-In Devices & Cable Pathways · Cable Coating, Foam & Accessories · Hilti / 3M / STI cross-reference