Moisture is the silent enemy of conventional insulation. It creeps in undetected, degrades thermal performance, promotes mold growth, and causes structural damage that can cost thousands of dollars to repair. Yet most builders and homeowners never think about moisture resistance when choosing insulation — until it is too late.
ThermBoard® rigid insulation boards are engineered to resist moisture from day one — maintaining full R-value performance, preventing mold, and protecting your building envelope for 50+ years with zero maintenance.
How Moisture Destroys Fiberglass Insulation
Fiberglass batt insulation is one of the most widely used insulation products in North America — but it has a critical weakness. Fiberglass absorbs moisture. When fiberglass insulation gets wet — from condensation, plumbing leaks, roof leaks, or high humidity — its thermal performance drops dramatically.
A fiberglass batt that is rated at R-19 when dry can lose 40% or more of its R-value when wet. That means a wall you thought was insulated to R-19 is actually performing at R-11 or less — costing you significantly more in heating and cooling energy every single month.
Wet fiberglass also creates the perfect environment for mold growth. Mold spores are present in virtually every building — all they need is moisture and an organic food source. Wet fiberglass provides both. Once mold takes hold inside a wall cavity, remediation can cost tens of thousands of dollars and require complete removal of the affected insulation and framing.
Spray Foam and Moisture — A Different Problem
Spray foam insulation performs better than fiberglass in terms of moisture resistance — but it introduces a different moisture-related problem. Spray foam can shrink and crack over time, creating gaps between the foam and the framing. These gaps allow moisture-laden air to penetrate the building envelope — leading to condensation, mold, and performance loss in exactly the areas where the insulation has failed.
Spray foam also requires precise installation conditions — temperature, humidity, and mixing ratios must all be within tight tolerances. Installations that fall outside these parameters can result in off-ratio foam that is brittle, shrinks rapidly, and fails to provide the moisture barrier it was designed to create.
ThermBoard® — Moisture Resistant by Design
ThermBoard® rigid insulation boards are highly resistant to moisture absorption — a fundamental property of the EPS and XPS foam core materials used in every panel. Unlike fiberglass, ThermBoard® does not absorb water. Unlike spray foam, ThermBoard® does not shrink, crack, or create gaps over time.
This means that ThermBoard® maintains its full rated R-value in humid conditions, in basements, in below-grade applications, and in any climate zone — year after year, for the full lifetime of the building. No performance loss, no mold risk, no structural damage from moisture absorption.
Below-Grade and Basement Applications
Below-grade applications — foundations, basement walls, and under-slab insulation — are among the most moisture-demanding environments in any building. Conventional insulation products are simply not suitable for these applications without extensive waterproofing measures.
ThermBoard® XPS-core panels are specifically designed for below-grade applications — providing excellent moisture resistance, high compressive strength, and consistent R-value performance even in direct contact with soil and groundwater. No additional waterproofing required, no performance loss over time.
The Long-Term Cost of Moisture Damage
The true cost of moisture damage to conventional insulation goes far beyond the cost of replacement insulation. Mold remediation, structural repairs, drywall replacement, and the ongoing energy costs of degraded insulation performance can add up to tens of thousands of dollars over the lifetime of a building.
ThermBoard® eliminates all of these costs — delivering consistent moisture resistance and full R-value performance for 50+ years with zero maintenance. The higher upfront cost of ThermBoard® rigid insulation is recovered many times over through lower energy bills, zero maintenance costs, and the complete elimination of moisture-related damage and remediation.
Protect Your Building with ThermBoard®
Do not let moisture silently destroy your insulation and your building envelope. Choose ThermBoard® rigid insulation boards — moisture resistant, mold resistant, and built to perform for the full lifetime of your building. Contact our team for free specification support on your next project.