I'm putting in an double hung double wide 400 series window, new construction. The installation guide calls for a 3/4 inch plastic drywall corner guard as a back dam.
The window dimensions are 4' 8 7/8" x 6' 3 3/8".
My questions; I'm adding 3/4' to the width for the RO. If I add 3/4" to the height will that be enough to accommodate the 3/4" back dam? I don't think so and was going to add 1". There will also be the flashing to consider. I'm using that self sealing sill wrap, which is about 1/8", for flashing.
Also, do you think a 2x10 header will be sufficient? This is on the top floor, nothing above but the roof with a 12/4 pitch above this window, 12/8 in the front.
Another question that is perhaps for another thread. Would you tear off all this old house wrap? Time and money constraints make it difficult, but my gut tells me I should. It's run vertically. In some places there is 15# felt under it.