You decide to build a deck.
Call in a builder, tell him that you want the deck to be this high (one step down from the ranch-slider), this long (just past Timmy’s window) that wide (two feet off the apple-tree);
You want it completed before your wife’s BD party, made it from hardwood, the handrail wide enough to support a wine glass and the balusters like the Jones’s.
The builder goes away, then calls and tells you a price. You agree, he comes back and builds it.
Verbal BIM in action. OK, maybe not exclusively verbal and maybe not quite BIM, but it has qualities that many other BIM can’t claim to have:
It has a completed building project and 2 satisfied parties: the client and the contractor;
The third party’s role, that of the designer is split between the client, the builder and commonly known design features (neighbour’s balustrade);
You also achieved two key features of a good BIM:
Integrity and endurance of project information!
In the future you may call back this builder to do your garage, a holiday home or an investment block of flats.
You’ll most likely abandon your unwritten-BIM approach to deliver the subsequent projects and you may or may not have them completed to everyone’s satisfaction.
I hope that the lessons you learned from verbal BIM stay with you.