One of the images which stays with me from my travels in Germany is the villages along the “German Wine Road” with their grapevines growing up the sides of houses and crossing roads and courtyards overhead. When I first saw them at a friend’s house, my initial response was to ask them if they were concerned about the deep roots causing problems with their foundation or the lack of air circulation behind the plants causing mold or other damage to the structure. I was greeted by a polite look of disbelief, followed by a chuckle and an explanation that the vines are generally considered to be good for the foundation and the house.
The basic reason for the vines being good for the foundation is that the deep and effective root structure of grape vines tends to actually draw moisture away from the foundation, to the point that the exterior foundation walls stay drier than the surrounding soil and the “exploratory” roots fan out away from the structure. As for the lack of air circulation, the recommended practice is to create a wire trellis a few inches off the wall for the vines to fill, which in turn allows for sufficient air circulation behind the vines. While I have not seen scientific evidence of either of these views, the fact that entire communities are doing this and buildings there have lasted for hundreds of years seems a fairly good indication that there is nothing inherently wrong with the idea of a house vine.
Having now had grape vines growing beside my last two houses for over 10 years, I have satisfied myself that house vines are a good idea. Possibly the most significant evidence I have of that is that one section of a basement wall which was frequently damp when I bought the house has had no issues with dampness once the house vine planted nearby matured while dampness has continued to occur in other locations.
Fully aside from any structural thoughts, having a grape vine growing against the side of a house has some other benefits. Mine is at a front corner of the house and has been trained to wrap around the front porch. It provides relatively low-maintenance greenery to be enjoyed while on the porch, and at harvest time it is by far the easiest of my vines to enjoy the fruit from. The proximity to an occupied area of the house keeps it relatively free of deer and raccoons. The thermal mass of the house helps to protect it from cold winter winds and frosts, while it also seems to accelerate fruit development and ripening.