Hi.  I’m a young contractor working on a 100 year old semi in Toronto.  I recently hired a more experienced contractor to assist me in vaulting the ceilings on the top floor.  Once we relocated the collar ties all we did was insulate directly under the roof joists and drywall onto that.  We also didn’t run vapour barrier as he said the house was not tight anyway and there isn’t continous vapour barrier anywhere else.  I am afraid that since we did not create any dead airspace between the roof sheating and the insulation that I may experience heat loss.  there is no room for venting at this point and I think that come winter, with no v.b. I may end up with a waterfall in my home.  Are these concerns warranted?  Keep in mind it is a very old home and is not built tight like new homes today.  Thanks!