Synthetic underlayment Question


Please see Picture below. I would like to place synthetic underlayment over everything is this the correct way to do it (my slope is kind of weird)? Also, this picture is missing the ice and water shield on the bottom right. And this is not to scale.


Running synethetic across a valley is a giant PITA. Best to lap it over the valley I+W and cut at the valley angle. Nothing wrong with running it with the valley on that smaller left side.


Thanks. Would about 6" in to the I+W be a good place to cut it at the valley angle?


Yes it would. That’s about how much we lap into the valleys.


Thank you for your help


“Running synethetic across a valley is a giant PITA.” Your not kidding. I started to do it across the valley and it just wouldn’t line up on the other side.

Here is what I am thinking of doing.



That looks like what we do.


Cool, I think I will use this method. Thanks


Would it be okay to run a piece of synthetic over the I+W shield in the valley (top to bottom)? Just for added protection so I don’t have to lap over the valley?


Ok, but not needed. Just extra work and wasted material