Metal roofing and siding question

[psu927]

When running ribbed metal roofing and siding, what do you guys do when a rib falls right where the corner post trim, or gable trim lands? I've heard guys say smash the rib flat. Seems like a pain to do it that way and just wondering if there are easier options

 

[RPH]

On the barn they have you trim a inch and half or so off the first piece to line things up across the seventy two feet.

 

[readhead]

We usually plan our layout before we start. You might need to cut the first sheet. You can also shrink or stretch the sheets to hit a mark.