What is the best practice to prevent leaky windows with fins all the way around them. Like the home depot American Craftsman. Thanks
I put window flashing tape all the way around then covered that with 6" wide strips of felt placed bottom sides top, in that order. Note if you're using tyvek or similar make sure to slit it so the top fin can fit under it. I used felt. Some windows recommend caulking the fin to the house but I found this pointless.
Thanks, I want to use felt too. How many inches overlap around the house? Where do you get flashing tape?
There's a Building Science note on this - http://www.gogreennmllc.com/documents/RR-0407_Install_Window_Series.pdf
The self-adhesive flashing is usually sold by lumber yards. Vycor is the common brand, with DuPont Straightflash being another. Supposedly you should use butyl flashing tape with vinyl and fiberglass windows - i.e. "Vycor Butyl" rather than "Vycor plus" (the DuPont product is only available in butyl). Of course the butyl costs more! Vycor does plastic "Vycorner"s for about $1.70 each that you can use if you're following the Building Science stuff to the letter (or you can use DuPont Flexwrap for the sill flashing, which wraps around the corners, but this is expensive stuff and the corners work out much cheaper). What with caulk, sill flashing, side flashing, corners, a few nails and a bit of building paper, it cost me about $20/window for installation materials when I stocked up this week.
PS Some places recommend taping the kraft building paper to reduce air infiltration. Does anyone know what tape sticks well to this stuff? Does the Tyvek tape work?
The Grace website also has information on proper installation.
http://www.graceathome.com/
The Vycor Butyl is recommended for high temperature areas like the SW. Other materials can flow down the wall in some cases.
This page has installation drawings for Grace products. Some of us prefer to get the building wrapped before installing the windows (like I was as I had a delay in my window order). Grace has instructions illustrating how to do that as well.
http://www.na.graceconstruction.com/template.cfm?page=/Window_and_Door_Flashings/dd_vycor.html&did=26
I did a 50% overlap on my felt and started with 2 layers on the bottom which gives 2 layer coverage overall. Put the felt on up to a few inches past the tops of the windows. Install the windows then start the next course of felt even with the tops of the windows so the bottom edge overlaps the window fin. On my house there is only about 6" between the top of the windows and the soffit so this was just a strip.
Also you may find you need to use a heat gun to get the flashing tape to stick good in cool weather.