But in the USA, the ironworkers have taken over the topping-out ceremony, wood or no wood.
A page at Columbia University (taken from The Ironworker) gives the history of the topping-out ceremony:
bq. At one time, Europe was covered with a vast forest. Those who inhabited the forest were dependent on trees for their survival. …
bq. Scandinavian mythology suggests that humans originated from trees and our souls returned to the trees after death, giving each tree a spirit of its own.
bq. Humans began constructing their shelter with wood. Before cutting a tree, they would formally address the forest, reminding it of the consideration they had always shown toward the trees and asking the forest to grant use of a tree for construction of their home. When the house was complete, the topmost leafy branch of the tree used would be set atop the roof so that the tree spirit would not be rendered homeless. The gesture was supposed to convince the tree spirit of the sincere appreciation of those building the home. …
bq. The custom of placing a tree on a completed structure came with immigrants to the United States and became an integral part of American culture in barnraisings and housewarmings.
This takes me back to learning Russian at Berlin University with Siegfried Tornow, who must have done linguistics and told stories about bears and trees in Indo-European times. (This was in 1967-68 – I wonder how old he is now?)