Railing wall causes gable wall roof projections

[Deirdre]

By any chance is your deck railing protruding past the exterior wall that it should be connected to?

Try pulling back on the deck railing and realign with exterior wall corner to see if this will clear up your problem.

On the other hand; if you are wanting the railing to project beyond, like an extension on the other exterior wall, as if you were going around the corner of the building, then it is suggested that you add an additonal railing piece at that point.