Plan your build with a minimum 45 degree pitch. Precipitation travels down the steep slope of the completed roof to the ground below.
The layer of thatch that covers a roof is at least a foot thick. The top inch or so of the thatch is the only part that ever feels the effects of the elements.
The steep pitch of 45 degrees is required for a thatched roof to ensure correct tension and maximum water run-off.
Thousands of pockets of air exist between and within the stems of the vegetation that makes up a thatched roof.
These air pockets act as an insulator providing an R-value of 40. Conventional insulation, such as fiberglass, usually rates between 30-50
The pitch of an existing structure may be 'built up' to achieve the proper angle.