why are you suppose to hold off from the center of the valley 4"-6" when installing metal ribbed roofing?

Question

also are you still suppose to use inside closure strips up the valley or is the another product to use.

Thanks

Answer 1

The reason is: Debris can build up on the valley and divert water up the high of the sheet. Leaving a gap insures debris will be carried down the valley to the eves.

Inside closers are designed to be used at the rake end. They will not be properly spaced to fit at the angles involved with valleys. They only fit at right angles to the sheet.

By the way "W" valley flashing will prevent water from running down one slope and up another. This should be specified.