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xlr8tion

Undersize replacement IGU's? Do or Don't?

xlr8tion
12 years ago

New to the board and want to thank everyone for their advice in advance.

I am replacing 18 IG's in my 10 yr old Simonton Dimension One PVC clad Casement and picture windows.

All IG's are 3/4" and all are inside mount with pvc stops.

Spoke to a Simonton tech and they suggested undersizing the replacement IG's 1/8" on the width(leaving 1/16" on the left and right) and 1/16" on the height due to their tight mfg tolerances and that the frames sashs are 10 yrs old.

Rep said better to be slightly "too small" (1/16") than too large due to over shimming and PVC expansion.

My glazier is not worried about the casements but said the picture windows(transoms that are 18.5H x 66"W may be a problem if the original installer over shimmed.

Long to short....which is more dangerous? Going with original mfg IG sizing or baking off am 1/8" on the width and 1/16" on the height?

BTW the replacement IG's are direct from Cardinal IG...3.1mm Low E 366/Argon/XL Edge Spacer......

Any opinions greatly appreciated as I have to order the IG's tomorrow

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