The number of layers or plies is dependent upon the design conditions and we usually limit non-metallic expansion joints to two or three layers.
![3layerbelt1](https://usbellows.com/wp-content/uploads/1990/07/3layerbelt1-300x175.gif)
The number of layers or plies is dependent upon the design conditions and we usually limit non-metallic expansion joints to two or three layers.