Roof liner system (100% of purlins covered)
Liner system (i.e. Optiliner) covers 100% of the purlins. The facing covers one entire bay at a time. The banding and facing is installed under the purlins, then the layers of unfaced are installed from the top. Assuming it's a retrofit project, then the unfaced is "pulled" between the purlins over the top of the facing.