I’m building a soundproof room in a garage for a friend, after having done it for myself, but am not sure about the ceiling. I was planning to use two layers of acoustic plasterboard (roughly 40kg per 2.4x1.2m), with rock wool in the middle. The joists in the garage are similar to this:
- 5F1FAC94-4C7D-460F-952F-5F4C39A8EEED.jpeg (31.2 KiB) Viewed 2090 times