Window Rough Opening Measurements 2

[Revv]

Hey Guys,

So on doors, typically we add 2" to the width for the RO dimension(depends on the doors but typically). What do you typically do for windows? Any adjustment for the vertical dimension?

 

[dik]

Same for windows... with 2" at the head... like doors. Maybe others do it different...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JLNJ]

For framed openings in steel walls (girts and metal siding) we use door size + frame size + 1/4" all around. I.e. a 36" personnel door with a 2" hollow metal frame gets a dimensioned opening of 40 1/2".

In masonry, the RO is dimensioned at door size plus frame (40" in my previous example) and the masons are smart enough to allow a little space for shimming. This probably results in an actual opening of 40 3/8", which is the coursing dimension.

Wood is not my bailiwick, but I know of at least on job where the architect or contractor misread the Pella installation instructions and all the window openings were framed out too small.

 

[XR250]

Is this because you are actually dimensioning the RO or just to design headers to the gnats ass? Seems like a bunch of liability if you are dimensioning them.

 

[Bob Black]

As a builder, I advise leaving a gap of an inch or so between the window and the soffit. We recently installed windows in a private home. It's quite large, 480m2. And I'll tell you there were such moments as wooden beams sagging on large openings. And the good thing is that there were smart measurers who persuaded the owner to reduce the height of the windows. We got to this facility to fix what was built by builders who do not have their hands in the right place. The house is big and frame. All made of wooden beams that were not properly dried and treated. And some of them twisted. As for me it is better to make a bigger gap and cover it from the inside and outside of the house with finishing materials. So you don't have to dismantle the precast concrete lintels over the window openings.

 

[MotorCity]

Bob - A 5166 square foot window is a rather large freakin' huge window.