Rock wool insulation is an A1 non-combustible insulation material and is widely used in rock wool panels, rock wool fireproof insulation material, and rock wool acoustic insulation material. The customer might have doubts like this: What if it rains or there is contact with moisture? Will it be damaged and develop mold and permanently lose insulation properties?

The simple answer is provided by the people at the United Insulation company themselves: it won't hurt the product to get it wet, and it will perform just as well when it dries. Why?

1) Water repellent and breathable

Top quality rock wool with an effective water repellent, giving a water repellency rate of at least 98% (En 1609). The water droplets will not only bead off the rock wool panels but also roll off, just as they do off a lotus leaf, with near zero absorption, i.e., less than 1 kg/square meters. It should also have good vapor permeability so that in case some water somehow gets in, it will immediately leave and evaporate, so that water accumulation will not occur.

2) Real impact when wet

- Temporary increase in thermal conductivity: the moisture film bridges the space between the yarn, which diminishes insulation capability, as with all fibrous materials.

- Increased Weight: can cause sagging but nothing rots or falls apart.

United Insulation affirms that after thorough drying, the original values of thermal resistance, fire resistance, and, in the case of rock wool acoustical insulation, sound absorption are all restored with no replacement necessary.

3)Clear Advantages over Other Materials 

Also, organic insulation materials like EPS and polyurethane have undergone permanent damage upon getting wet. In rockwool fireproof, despite being subjected to infiltration by water, the material remains non-combustible under class A1 after getting dry. Search results for "rock wool insulation when wet recovery" and "does rockwool lose R-value after drying" show that regular rock wool is far superior to glass wool in its ability to recover in humid environments.

Practical suggestion:

Waterproof membrane recommended when transporting and storing product. Vapor barrier recommended when building. Rock wool panel recommended when piping. All of our rock wool export product is CE marked and has water repellant technology, offering increased water repellency and drying rates.

FAQ 1: If rock wool insulation is exposed to moisture, does it have to be replaced?

No. Indeed, when it is dried completely—natural air drying or low-temperature drying—it will certainly restore properties of insulation, fire resistance, and performance of sound absorption. According to United Insulation Company, there are no changes in any physical or chemical properties.

FAQ 2: Does the rock wool fireproof insulation remain fireproof even after wetting?

Yes. The non-combustible characteristics of its A1 classification and the melting point of above 1000 degrees C remain unaffected when subjected to drying. It provides short-term fire resistance even when it gets wet.

FAQ 3: Does the presence of moisture have a bearing on sound insulation for rock wool soundproofing materials?

A short drop in performance is possible, but the NRC Sound Absorption Coefficient reverts to its performance when dried. The breathability of the design makes it effective in a high humid setting such as a recording studio or a cinema.

Want highly water repellent rock wool panels? Or maybe fireproof or acoustic insulation? Well, contact United Insulation! We have rock wool products that don't fear getting wet!