We are in the process of building a timber framed house. The frame is now up, and block work has been built to the outside of the house. Our window fitter has fit the upvc windows, however they have been fit to the blockwork rather than the timber frame. Is this correct? I was expecting the windows to be fit to the timber frame, as now there is a gap between the frame and the windows, which would surely lead to heat escaping! Can anyone advise what is the correct way of fitting the windows? Thank you!