Originally Posted by johnny331
I'm looking to mull two 3x5 windows together. I was just looking for some advice. Do I overlap the nail flanges completely, will I need special flashing? How does a mulled install compare to just a single window install?
You should not have to overlap any nailing flanges & you should not need any special flashing.
You essentially install the windows 'next' to each other (usually there is at least two 2x4's placed vertically in between, or stock that will help complete the width of your mullion strips) and then install the trim around the windows to make them look like they are part of one large framed window package arrangement.
You see, a ''mullion'' is a vertical strip of wood (or other trim material), placed between the casements or panes of a window. So, mulling simply means to tie the individual windows together using trim work (this is done on the interior and the exterior sides).
Factory fabricated mulled windows (one framed unit):
Example of 3 different windows installed, and then mulled & cased on the work site in order to create ''one large framed 3 window unit''.
Example of 5 windows. Two in the middle were mulled at the factory. Each installed seperately, you can see the nailing fins clearly do not overlap in any way:
Finished product prior to painting (note how this now looks like ''one complete window arrangement''):