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Window and Door installation confusion

Posted by reneophyte (My Page) on
Sun, Apr 4, 10 at 18:05


I'll be installing a couple of french doors (exterior) and windows this weekend. It seems everyone's got slightly different ways to "properly" install windows and doors, but some of the information is conflicting. If anyone could please advise the proper installation, I'd appreciate it greatly.

Specifically, the windows and doors are all Marvin Integrity. My house is located in the northeastern US, and has only sheathing on the outside (no house wrap). I plan on siding the house after all windows/doors are installed. According to Marvin's instructions, I should be installing grade D building paper around the rough apron (windows only) and jambs wrapped inside the rough opening. They specify a perimeter sealant application, then the window, and then flexible flashing material OVER the nailing fin and drip cap.

Then I came across this video:,,1632386,00.html

Here Tom Silva applies only the felt paper apron, then uses the flex flashing around the sill framing, but only flush to the jamb framing. He then installs the window (without mention of a sealant), levels, plumbs, etc, and places a final layer of flashing at the head jamb (overlapping the window, but no mention of a drip cap?).

I'm inclined to follow the manufacturer instructions as to not void the warranty, and wrap the jamb and sill framing with building paper, and use the flex flashing over the nailing flange. Is this what is normally done?

Also, Marvin doesn't have any info about flashing the sill in the french door instructions (just construction adhesive is used). My installation has a bit of a roof overhang protecting it, but there's also a deck that the doors will lead out onto, and I want to be certain I'm applying any prudent application(s) on the sill. I see there are plastic corners and other rigid sill plates available on the market. Is this necessary?

Thanks in advanced for any of your shared wisdom!

Follow-Up Postings:

RE: Window and Door installation confusion

There are better sill flashing membranes now that allow for a 1 piece corner as opposed to cutting the membrane in the corner. Tyvek makes several nice products in the membrane applications.

There are also rigid water management/sill pan applications that work very well.

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