drip edge use on aluminum window install
chrisjohns
| Posted in Construction Techniques on
DIY question:
I understand drip edge serves to keep water moving out away from the house envelope and to protect window and trim woodwork from standing water.
Is is common practice to use drip edge on top of aluminum windows which have nail flanges?
Is the drip edge effective? on the top edge of the window, I think caulking the cedar to the aluminum to side is as good as seating the cedar in sealant on top of the drip edge. The sides and bottom of the window to cedar interface may suffer a little more in the case of no drip edge.
Any thoughts on that??
Replies
First, check the inatallation instructions from the manufacturer. Generally, they are required. You must also flash the window properly with a window wrap and caulk behind the nailing flanges. ASTM requires 9" "window wrap". There have been articles in both FHB and JLC on the subject.
The manufacturer (Milguard) does not state a drip edge requirement. The ROs are covered with Ice and Water Shield.
Thanks.
So, you have wrapped the RO, then installed a AL window with flanges, right so far?That leaves the top flange facing uphill right?So any water running behind the siding will run behind the flange and into the house, right?So you need another slice of I&W to go over the top flange and under the house wrap.now then, we get to the drip metal. I trim out my windows with casing of one kind or another on the exterior most of the time. So I place the drip metal over the head casing.If your flange is integral and has no opennings I see njo reason for an additional drip in conection with it.Be careful about the side caulk. You don't want to do it in such a way as to trap water.Always think like a drip
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
thanks. i do plan to put the second slice of grace, then bring the 30# down to the metal flange.
i took a look at a metal sided building (that was done pretty utilitarian but solidly). they had a metal drip over the top of the windows! some sort of j metal on the other three sides. not sure why. might just be to keep running water off the wind glazing/seals and seams between the window and J metal.
Then I will NOT calking the bottom and leaving some (1/4") gap along the two vertical sides to facilitate draining as you suggest. that is a good tip.
thanks.
Piffin -
I got a question for you. I'm designing a house (for myself) that is to be traditional 3 coat stucco. I've specified that the stucco terminate into casing bead flashing around all 4 sides of the windows with a 3/8" backer rod between the casing bead and the window side. Also at the bottom too. The top is to have galvanized flashing hanging out over the window flange. I plan on using a highly flexible caulk over the backer rod.
Would you do it this way? See pic.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
We can imagine something that only exists in our heads, in a form that has no measureable, tangible reality, and make it actually occur in the real world. Where there was nothing, now there is something.Forrest - makin' magic every day
My stucco experience would get you a cup of coffee with a dollar added...But the details look good, there is a drain channel left. It is in how you lap all that paper and J metal at the corners.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!