The only way to improve the quality of the underlayment was to make it thicker or add another layer.
Peel and stick roof to concrete.
Rubber flexx waterproofing and seam tape is an easy to use peel and stick repair material to seal and fix leaks and problem areas.
Direct attachment peel stick to the plywood then use 2 foam process to attach the concrete roof tiles.
Go to roof online s vapor barriers page.
Until recently all shingle roofs had the same type of underlayment.
They all used rolled asphalt felt material commonly referred to as tar paper.
Typically ranging in width from 4 to 12 inches these peel and stick membranes greatly simplify the task of creating a continuous barrier to water entry around doors windows decks and other problem areas.
Using peel and stick underlayment makes a better roof.
Peel and stick flashing tapes types uses applications.