I am installing a new inset medicine cabinet. I need to add about another 1.5” inches in height to get the new one to fit. I would like to remove the header on this (it’s a true 2” stud) and replace it with a piece of 1x4. I’m pretty sure this is setup just to support the original cabinet. Would there be any harm in doing this (or possibly removing the header altogether)
You can do a number of things here:
Shorten the stud board coming down to the header and move the header up 1.5” to 2” inches (I would do that ) - a nice oscillating cutting tool would make that easy to do right in place.
I would then install my cabinet - and I would have a sturdy upper frame for it as well.
You could remove it , replace it with something thinner .. but really why spend the extra money for wood - just cut the stud board and move the thing up the distance you need.
You want to follow the instructions given to cut the upper short stud some and then move the header up the requisite amount. Make sure to re-nail the lower end of the short stud to the raised header.
Please ignore the noise here regarding removing the header entirely. You do not want to do that since that upper short stud lower end would be unsecured and will create a spot on the wall that can flex. This can be especially problematic if someone tries to attach a load on that stud from the opposite side of the wall. Just imagine how bouncy it would be trying to hammer in a nail to that stud from the opposite side.