green sound absorbing material (norfork reed thatch?)

I am interested in green sound absorbing material.. it is said that "At least a foot thickness of thatch on top of a roof also helps thermal retention. Norfolk reed, commonly used to thatch roofs in the United States and Britain, offers an insulation or R-value of 40. Conventional building insulation, such as fiberglass, usually rates between 30 and 50.[4]" I like to know STC and sound absroption coeficient of thatched roof and wall, according to different thaching materials. but is there a data about this? if the coeficient and stc is great... than could we replace fibergalss with this almost free materal? i assume that the stc is bad but very thick thatced wall, like 24inch, might yield some good stc rating. I am also interested in hemp thermal board...