Thermwell B2 Caulking Cord 90 Foot 19 Oz Gray

Product Description

The THERMWELL B2 is a gray, rope-style caulking cord designed for sealing gaps, cracks, and joints around windows, doors, and other building envelope penetrations. Sold in a 90-foot, 19-ounce roll, the Mortite-formula cord presses into place without tools, conforming to irregular surfaces for an airtight, weathertight seal. It is a non-hardening compound, which means it stays pliable for easy removal or repositioning. HVAC technicians, insulation contractors, and general maintenance professionals use this product to stop air infiltration and reduce heating and cooling losses at seams and rough openings.

The B2 caulking cord is suited for residential and light commercial applications. Typical uses include sealing around window frames, door frames, sill plates, and pipe or conduit penetrations through walls. The cord is pressed directly into gaps by hand and requires no caulking gun. Its gray color blends with masonry, concrete, and most painted surfaces. Each roll provides 90 feet of continuous coverage, making it practical for whole-unit or multi-opening jobs without frequent restocking.

Key Features

• 90-foot roll provides extended coverage per unit
• 19-ounce fill weight for consistent cord diameter throughout the roll
• Non-hardening, pliable compound conforms to irregular surfaces
• No caulking gun required — applied by hand
• Gray color suitable for masonry, concrete, and painted surfaces
• Removable and repositionable without damaging substrate

Compatibility

Designed as a general-purpose weatherstripping and air-sealing cord for use at window frames, door frames, sill plates, and wall penetrations in residential and light commercial construction.

Installation Notes

Installation does not require licensed trade credentials, but licensed HVAC technicians and building envelope contractors routinely specify this product for air-sealing at equipment curbs, duct penetrations, and rough openings. Clean and dry the substrate before applying the cord to ensure proper adhesion. Press the cord firmly into the gap or joint by hand; no primers or adhesives are needed. For best results, apply at temperatures above freezing, as very cold conditions can temporarily reduce the compound's pliability.