showcrop
Well-known Member
(quoted from post at 05:12:12 09/12/23) Most steel manufacturers now recommend installing the screws on the flats right next to the ribs instead of on the ribs themselves to prevent that issue of screw holes enlarging. Even when screwed on the ridge, however, I've only seen that issue of holes enlarging on old, old barns with the
lead-shielded nails or the old-style of sealing washers, and old-style profiles. For many years now, steel profiles have been such that the expansion/contraction is taken up in the body between the ribs and thus the holes don't enlarge due to expansion/contraction. I have steel on 4 barns,
two machine sheds, and two houses (plus a couple of smaller fuel sheds etc.). The newest one is still 32 years old and shows no signs of leaking. The only one that has leaked is the oldest barn, with an old, 'wave' profile and the old-style of screws with the lousy sealing washers (the old
style didn't have the cupped washer over the rubber to sinch it down around the hole.
The last steel roof that I was involved with was replaced with shingles after around twenty years.