http://www.flickr.com/photos/kestenbaum/sets/72157606305626465/

Now that I've seen the pix, I think this is a work in progress and it's too soon to say what the hell they're doing.  But leaving the old ashfault shingles in place until the new roof is on will keep the rain out of the old portion of the building until then.  I don't get the combination of gable and shed roof on the addition, but my guess is that there's some phasing problem they're accommodating by not having built the back wall of the addition (which would explain the shores under the ridge), and that the addition will eventually have a regular gable roof. 

 

Send more pix as it progresses, so everybody knows whether I'm full of shit.  On second thought, nobody needs your pix for that.

 

Ralph