In what circumstances is a 1.0m wide underlay preferable to 1.5m?

[epsilonGreedy]

Looking at builder merchant web sites both widths of underlay are mainstream hence my confusion.

 

I assume the fewer overlaps from using 1.5m rolls on a new roof is preferable. In the case of my hipped, L-shaped 30 degree pitch roof should I consider using 1.0m rolls? The felt might have to cope with a couple of months of exposure.

 

Background Info: Cold attic space, 600mm truss centers and the felt will be drapped without sarking support. 

[PeterW]

1m gets used for hips and valleys sometimes to stop having to cut down rolls. Tend to use 1.5m

on big roof sections. 

[epsilonGreedy]

4 minutes ago, PeterW said:

1m gets used for hips and valleys sometimes to stop having to cut down rolls. Tend to use 1.5m

on big roof sections. 

 

 

Thanks. I was concerned I might have to buy a roll width that was a nice round multiple of the batten centre distance.