Portals Plus 38131, Large RC-2A Straight Sided Roof Curb- 18" High

The Portals Plus Large RC-2A Straight-Sided Roof Curb 18″ High (POR-38131) is engineered for rooftop applications where major penetrations (8″-12″ diameter) occur through decks with lightweight fill or tapered insulation. The curb box is made from 18-gauge galvanized steel with continuously welded corner seams, includes a wood nailer at the top, and is factory-insulated with 1.5″ thick 3 lb rigid fiberglass. The cover is designed for use with a 14″ collared opening and an EPDM compression-molded C-182 cap with a Snaplock stainless steel clamp.

Key features:

• Designed for large-diameter penetrations (8″-12″) in one curb system.
• Constructed of 18-gauge galvanized steel with welded seams for durable weather and structural performance.
• Factory-installed rigid fiberglass insulation to control condensation and thermal bridging.
• Straight-sided 20″ × 20″ footprint with 18″ height for level mounting above tapered insulation or fill.

• SKU: POR-38131
• Product type: Large RC-2A Straight-Sided Roof Curb 18″ High
• Dimensions: Length 20″ × Width 20″ × Height 18″ 
• Fits pipe size: 8″-12″ diameter penetrations
• Construction: 18-gauge galvanized steel with integral base plate and continuously welded corner seams 
• Insulation: 1.5″ thick 3 lb rigid fiberglass board, factory installed 
• Application: For decks with lightweight fill or tapered insulation; intended for use with a large-collar portal system.
• Cover interface: Designed to pair with a 14″ collared opening and an EPDM cap model C-182 with Snaplock clamp.

Q: Can this curb support a large-diameter single penetration through the roof?
A: Yes; it is specified for pipe sizes from 8″ to 12″ diameter and provides a level mounting base above tapered insulation or fill.

Q: Will the insulation inside the curb help reduce condensation and heat transfer?
A: Yes; the factory-installed 1.5″ thick 3 lb rigid fiberglass insulation improves thermal performance and helps manage condensation under the curb.

Q: Is the footprint of this curb suitable for heavy rooftop equipment or piping layouts?
A: Yes; the 20″ × 20″ foot print and straight-sided design provide a broad, stable mounting surface suitable for large penetrations and robust setups.

Q: Can this curb be used on existing rooftop fills or retrofit scenarios?
A: Yes; it is appropriate for roofs with lightweight fill or tapered insulation, and can be retrofitted provided the structural support and deck conditions permit.