Since 1858, we have been engineering the insulation and roofing systems that protect buildings, conserve energy, and improve the built environment across North America and beyond.
Johns Manville is a wholly owned subsidiary of Berkshire Hathaway Inc. We manufacture a broad range of insulation, roofing, and other specialty products for commercial and residential applications, with manufacturing operations on four continents and distribution through a global network of technical sales representatives and distributors.
What began as a single asbestos importation business in New York has evolved over 166 years into one of the world's most respected manufacturers of fibrous glass and related building materials. Each decade brought new technical breakthroughs — and a consistent commitment to quality that outlasted every market cycle.
Henry Ward Johns establishes H.W. Johns Manufacturing Company in New York City, initially importing and processing asbestos insulation materials for steam-era industrial piping.
H.W. Johns Manufacturing merges with Manville Covering Company to form the Johns-Manville Corporation, creating a combined entity with broader product coverage and distribution reach.
Johns Manville becomes an early pioneer in manufacturing fibrous glass insulation for commercial and residential construction, replacing earlier mineral-based insulation methods.
Following significant asbestos-related litigation, the company enters Chapter 11 protection, restructures, and emerges with a new corporate identity and a commitment to asbestos-free product lines.
Berkshire Hathaway acquires Johns Manville, providing financial stability and long-term capital for continued manufacturing investment and global expansion.
Today Johns Manville operates 40+ manufacturing plants across four continents, producing 3,000+ specification-grade insulation, roofing, and building systems products for global markets.
Every thermal performance claim is backed by ASTM C518 or C177 test data, available on request — no marketing estimates, only laboratory-verified values.
Our roofing systems are installed exclusively by JM-certified contractors who have completed factory-approved training and have access to full warranty coverage.
Master specification sections, CAD details, and SpecBuilder-compatible files are available for every product category — reducing specification time for architects and engineers.
Fire resistance, wind uplift, and material emissions testing is conducted by UL, FM Global, and GREENGUARD — not internal laboratories — ensuring verifiable, unbiased results.
With 40+ manufacturing plants across four continents and established distributor partnerships in 40+ countries, we maintain lead times that keep construction schedules on track.
We publish the conditions under which our products perform differently from rated values — including temperature dependencies for polyiso R-value and installation quality effects on batt performance.
Contact our technical sales team to discuss your project specifications, find a certified contractor, or request product samples.
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