It’s a community for those who take great pride in their craft and are always looking to learn about better materials and installation techniques that will ensure their homes are comfortable, beautiful, efficient and built to last. When you join the R‑Class, you’ll receive support and training by our team of residential building pros, samples, potential rebate savings and more. ROCKWOOL high-performance stone wool is in a class of its own — and so are the builders who make up the R‑Class.