Snow load... - I'm guessing there's a substantial snow load in your clients' area? We're considering a similar covered walkway (extra room!) to join the house to the garage.
It looks like just such an attractive and functional and well-thought-out idea; thanks for posting so many enlightening photos! »
Covered, wind-protected breezeway. It helps protect a nearby outside 'room' from strong prevailing winds, and keeps the rain off you between house and barn.
Dan