Upper sash sagging
my 1925 windows on my bungalow are sagging where the upper and lower sashes meet. this gap lets in a ton of air and the window locks are useless. Can i simple pull the windows out and clamp them back into the orignal shape? it looks like the sash has almost come out of the vertical wood slats in the windows.
Re: Upper sash sagging
I do a lot of window rebuilding of this age, and it sounds as if the sash need to be removed, and remove the glass. By getting the glass out you can then tighten up the mullions and muntins by clamping and glueing the intersections.
I suspect you have serious rot in places you cannot see.
Abatron liquid wood epoxy is an excellent product for this type of repair.
I begin by carefully removing the glazing putty, a sharp utility knife is handy, a putty knife, and sometimes a chisel..do not use a heat gun, you will break the glass. You may any way. If it is the old "wavy" glass, expect a HIGH price..here I have seen a pane of 10"x20" go for 50.00$ !!!!!!!
Now while it's out strip the ext. paint, that is where you can employ a heat gun and shavehook type sc****rs.
Epoxy, clamp square, and when cured, do what ever sanding you need to do. PRIME everything with OIL BASED Primer ( ZInnser's Cover stain, is a good choice, or SW's A-100).
Install glazing and putty ( I do something different, I make glass stops out of Azek triangluar shaped rips and 23 ga pin them in).
Paint, and rreinstall..not fun work, but it's either that or replace the windows, I have found that it is easier / faster for me to sometimes make a new sash, vs. repair an old one that is too far gone.