Metal roofing has a deserved reputation for lasting. It sheds snow and driving rain better than anything else we install, it does not lose granules, and a well-detailed metal roof will outlive several shingle roofs on the same building. Almost every metal roof that disappoints, though, disappoints for the same reason: the panels were fine and the details were not.
The detail that matters most is movement. Metal expands and contracts measurably with temperature, and a long panel run moves more than people expect across the swing between a February night and an August afternoon. Standing-seam systems handle that with concealed clips that let the panel slide; exposed-fastener systems handle it with correctly sized holes and the right washers. Pin a panel so it cannot move and it will find a way to relieve the stress anyway — usually by elongating its own fastener holes, which is exactly where it then leaks.
The second detail is terminations. Ridges, hips, eaves, rakes and anywhere the roof meets a wall all need trim that sheds water outward and closures that keep wind-driven rain and wildlife out of the panel profile. This is the part that gets improvised when the trims were not ordered to match, and improvised terminations are where a metal roof leaks first.
The third is contact. Metal roofing does not like being fastened through with the wrong fastener, penetrated carelessly, or set against incompatible metals and treated timber without the right separation. None of that is difficult — it just has to be decided before the panels go up rather than worked around afterwards.
We install standing-seam and exposed-fastener metal on houses, barns, shops and commercial buildings, with the trims and closures to match. Call New Generations Services at (240) 375-4853.