This insulation article of mineral wool or "rock wool" illustrates and describes insulating materials of mineral wool or rock wool and slag wool. Rock wool or insulation of "rock wool" is also known as mineral wool and slag wool, although there may be differences between the components of these insulation. We describe the insulation of old or old mineral wool, as well as the modern insulation mineral wool products that are still used in buildings.
This document assists buyers, owners or inspectors who need to identify various insulation materials in buildings by simple visual inspection. We provide descriptive photographs and texts of various types of mineral wool insulation and describe their properties, how they are made, health and maintenance concerns, and their insulating values.
The insulating R value of mineral wool
This is a good insulation material and has a better "R" value and more sound reduction capacity per inch than some glass fibers. Rockwool insulation cans have an R-value of about 3.14 to 4.00 per inch. The insulation of blown rock wool or mineral wool like the one shown in our photo above attic has an R value of about 3.10-4.00 per inch.
Other sources we investigated indicated that the slag wool filler insulation had an R-value of about R-2 to R-3,3 and a source claimed an R-value of 4.1 per inch for rockwool. [Home Energy Magazine Online, July / August 1997]
A rough estimate is to assume that mineral wool made from rock or slag has an R value of about 3.35 per inch in the form of wood and an R value of about 2.25 in loose filler installations.