What size window to order?

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Posts: 11
Joined: Mon Jul 12, 2021 6:30 pm

What size window to order?

#1 Post by MRWindows »

Hey everyone,

What size new construction window should I order to replace the window pictured?

Will a 89.25” x 41.25” nail fin window fit? Or should I go a bit smaller/bigger?

Any help would be much appreciated, thanks!

Delaware Mike
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Joined: Fri Nov 19, 2004 10:44 am
Location: South Jersey, Delaware, Philadelphia area

Re: What size window to order?

#2 Post by Delaware Mike »

With existing flanged builder's aluminum windows the actual side view of the window/jamb can be offset with a different interior (fits the rough opening) and a smaller exterior that would stick off the face of the sheathing. You don't want too big or small obviously. Some have flat jamb builds meaning that they're more like modern vinyl in that if you pull the tip to tip frame to frame exterior measurements the interior will be the same.

What I suggest you do would be to record the exterior measurements where the aluminum frame terminates and then go to the interior and compare to those measurements. I know that the finished jambs, stool, and trim might obscure but it's sort of easy to "cut in" where you would know modern drywall and jamb extensions will sit hard to the jack studs. Just make a little pencil mark on the face of the sheetrock or trim casings of about 3/8" to 5/8" and pull that measurement for width. The bottom stool (most refer to as the sill) will be 11/16" or about 1" if rabbeted. Do the same for that. Compare measurements, if same you're good, if the exterior differs greatly go with the interior minus the room for squaring and spray foam.

uncle eddie
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Joined: Tue Sep 18, 2012 7:52 pm

Re: What size window to order?

#3 Post by uncle eddie »

The guy that is going to install this should be measuring. If its you, and you don't know how to measure it, you shouldn't be installing it.

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Windows on Washington
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Location: DC Metropolitan Area-Maryland/Virginia/DC

Re: What size window to order?

#4 Post by Windows on Washington »

You planning on pulling the trim? If so, pull it now, get your RO size from the outside, check your jamb depth on the inside, and post those data points up.

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