My house was double glazed a few years ago (pretty standard white uPVC) and I have just found that a timber (4 x 2) into which one large (floor to ceiling) window is fixed has some rot in it. Since I am going to be doing some work on the wall on the other side of this timber, it seems sensible to deal with the rot at the same time. Now I could cut the section at the bottom out and jiggle a new bit in, or I could replace the whole lot (which I'm sure is the right thing to do). I presume the frame of the double glazing is screwed into said timber so, since I'll be exposing the 'other' side, I was thinking that deglazing the frame but leaving it in situ would be the way to go.
So, my question is how to extract the sealed units from the frame so I can get at all this. I know these units are glazed from the inside but it's not entirely obvious how to remove the beading that holds the glazing in. I kind of assume that it's a matter of sliding something thin into the side of the bead and levering it out but I don't really want to wreck it without knowing what might be underneath. The beading seems to be a pretty close fit and I'm sure it's all fairly prone to denting and scratching. Does anyone happen to know whether a) all d/g units are basically the same ( in which case I can have a furtle around at Wickes or somewhere to get a good idea) or b) if there's a good source of (ideally illustrated) information somewhere, where I could see the various configurations before going at this.
Thanks chaps...and no prizes for the person who suggests going at it with and SDS drill.....:)