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Window install question (is it proper or not)

Posted by scotkight (My Page) on
Sun, Jan 5, 14 at 18:28

Is there any proper reason why an install of a standard window would have the bottom flange taped to the siding of the home?

As in, you make a sill, put the window into the rough opening and on top of the sil, level/plumb etc, then nail the four flanges on the outside into the siding/housewrap. Also caulk etc, as per manufactures requirements.

One done with that, my understanding is you then tape the two side flanges to seal the PVC to the house wrap. Then you take another single piece of housing tape and put it across the top flange of the window and over the two other bits of tape to seal it there.

The bottom flange is (to my knowledge) always left un-taped to let any moisture that may somehow get behind, out.

Is there *any* reason to actually tape that?

Follow-Up Postings:

RE: Window install question (is it proper or not)

You may tape the sill (prior to the installation of the window) but the bottom flange is left open in a majority of the cases.

If there is a sill pan, that can be taped but again, the flange should be un-taped.

RE: Window install question (is it proper or not)

Sorry to be pedantic, but you did use the magic word "should."

Is that an absolute rule?

I have seen (in pre-construction) for a few communities where this was done. I doubt anyone else has even noticed and I want to know if I should or shouldn't mention it as an issue.

RE: Window install question (is it proper or not)

For years the window fin was flashed on all four sides to prevent any water from getting past the window. The new school of thought is that water will eventually find its way into the opening (and it may not necessarily be coming from the window opening) and it needs a way to get back to the outside. This is why it is today's way to leave the bottom open. AAMA's Installation Masters training is at the forefront of this.

RE: Window install question (is it proper or not)

Excellent advice from eastbay. The lower flange is not flashed to allow moisture to escape when needed. This is the latest and greatest procedure. Is it absolutely necessary for a great product and install? No. Is it cya for both you AND the installer ? Yes. If it were my house, I would not tape the lower. Furthermore, an installer that wants to seal that area throws up red flags that they are lacking in other areas.

RE: Window install question (is it proper or not)

I can't stand that all I think of is Family Guy when I hear the word pedantic.

I agree with the other guys and Scot and I discussed this project yesterday. He has several uphill battles with the builder but certainly is and informed and motivated consumer.

Here is a link that might be useful: Video Link

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