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tom31415926 06-28-2012 01:58 PM

flashing replacement window
1 Attachment(s)
I can't seem to find any information on this specific topic.

We had our windows replaced some years ago with Anlin windows. We have no complaints about the windows and like them. We are now embarking on a project to re-side the house because the stucco is cracking. We would like to keep the Anlin windows, but understand that it will probably be necessary to remove the windows and re-install them.

It appears that the Anlin windows do not have a nailing flange, but are attached by screws through the sides. On the exterior, the window has only a "fin" which is slightly larger than the window frame. (See the attached picture; the window interior is towards the camera). The gap between the fin and the house is caulked as the only defense against water cascading down the exterior wall. The fin is not covered (or overlapped) by any weather resistant barrier.

Now I plan to install 7/16 OSB, Tyvek house wrap, and 5/16 hardi panel (in that order). What is the best way to use flashing and/or sealant to re-install these windows? The flashing techniques I see demonstrated on the internet look great, but I have no window flange to overlap with flashing.

The sealant that is there now is rather tough stuff; should I use this for the re-install? If so, what is it?

Any advice would be appreciated.


AGWhitehouse 06-28-2012 02:28 PM

Can flanges be retrofitted? I know that most vinyl windows have the channels molded into ALL the frame types so they can use the same extruders to save on manufacturing. Then if a window needs a flange, they slide it into the channel, miter cut and weld the corners. Give them a call.

A window without a flange is considered a "replacement" window while the a flanged window is a "new construction". I cannot and do not recommend installing your replacement windows in a new construction type of opening that you are describing. It is practically impossible to flash it properly...sorry

HomeSealed 06-28-2012 05:45 PM

I have to disagree completely with AG Whitehouse. There is no reason for your windows to be removed, and fin-less windows can and are installed in RO's regularly for a variety of reasons. It may not be ideal, nor is it the cookie-cutter method that framers and new construction guys are used to, but you have what you have so you just need to work with it.
What you will need to do is some high-end flashing work, which may be above your level of expertise and equipment. There are a few different ways to attack it, but my recommendation would be to call a professional (at least for this phase of the project).

CopperClad 06-28-2012 06:08 PM

And if it didn't have a nail fin.. Didn't they leave the frames of your old window in?

Tom Struble 06-28-2012 06:38 PM

re stuccoing would give you the opportunity to put a drip cap over the stucco fin,you could actually close of the sides and the head wth a Z bend flash that like a flange,leave the bottom open

tom31415926 06-28-2012 06:49 PM

more info
Thanks for the help.

AGWhitehouse inspired me to call a local Anlin installer.

Yes, the old frames are still there.

The local installer recommended that I remove the old frames when I remove the stucco. The old frames should have flanges for flashing. After demolition, I should install the OSB first. Then I should re-install the old frames into the OSB , using all applicable flashing techniques, incorporating the house wrap. Then, install the concrete siding. The local installer said I should seal the replacement window to the old frame. In this way, I take advantage of the flashing of the old frame. Then, the sealing of the replacement window "fin" to the concrete siding is only one part of the protection. I told him how the replacement windows are installed now, with only a seal to the stucco and no seal to the old frame and he called that an incorrect installation.

I'm still not clear on how to accomplish the seal to the old frame, but if I can solve that I would feel like this is do-able. I can understand the position of AGWhitehouse, that nothing beats the window system designed for new construction. One helpful thing in my present case is that I have a one-story house and the tops of the windows are under the eaves; not too much water cascades down onto the top of the window.

Comments, anyone?


Tom Struble 06-28-2012 07:18 PM

i really don't understand what you or the local installer are talking about,what makes you think the old frames have a fin?

a fin is an installation aid..nothing more

CopperClad 06-28-2012 07:19 PM

He's talking about the nailing flange of the OLD window that is original to the house.

CopperClad 06-28-2012 07:25 PM

If I were you.. Since you're already going to be removing the old frames anyway.. Just build out your opening to properly fit your replacement window. Just add 2 1/4 trim on the inside sheetrock rock to picture frame it and then a little paint and your done. Are you able to install a flange on your block frame Anlin? I'm pretty sure you can.. And from there it seems you understand how to do the rest.

Tom Struble 06-28-2012 07:38 PM

what makes you think the OLD windows had a flange?

CopperClad 06-28-2012 07:47 PM

100% of the thousands of windows I set in new construction had flanges. Whether it was vinyl, aluminum, or wood.

Tom Struble 06-28-2012 07:57 PM

oh well if your that sure:whistling2:

HomeSealed 06-28-2012 08:58 PM

Maybe I'm missing something here,but why is the old frame being removed, followed by reinstalling replacement windows that were sized to fit within it? Am I reading that wrong?.... That would be utterly pointless because the windows would then be undersized for the RO and need a buck frame built anyway,which is essentially the same thing as leaving the existing frame... I realize that things are done a little differently out west, so maybe there is some regional difference?:huh:

tom31415926 06-28-2012 10:14 PM

fins and flanges
May I attempt to define two words based on the context of the comments?

I gather that a "fin" is flush with the exterior of the window and slightly too big to fit through the hole made for the body of the window. As such, it is an installation aid. Water getting behind the fin may well get inside the wall, unless the body of the window is sealed to another surface that is water-tight to the exterior of the wall (I'm still not sure _how_ that is done).

A "flange" is not flush with the front of the window and may leave some of the window frame proud of the surface to which the flange is nailed. The flange is integral to the window and hence any water in front of the flange will remain outside the wall. Flashing makes sure that any water is kept in front of the flange.

Have I defined flange and fin correctly?

Yes, we cannot be sure that the old frames had flanges or that the frames will be re-useable (i.e., easy to integrate into new construction).

I'll have to do the demolition on one window to see what's there.

Thank you for the vigorous discussion. All of the possibilities raised convey useful information to me.

I'll be sure to post follow-ups. But continue to share your ideas in the meantime.



tom31415926 06-28-2012 10:21 PM

reply to HomeSealed

Here is the picture as I understand it.

The old frame has a flange (we think) but it is embedded in (or behind) the stucco. We will be removing the stucco

The new exterior will include 7/16 OSB, with house wrap over it. The old frame needs to be flush with the surface of the OSB, so it needs to be removed and reinstalled.

If I leave the existing frame in place, it will be behind the OSB and water in front of its flange will contact the OSB.

I have not done this before and am echoing the guidance that I am getting.


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