underpropping

The party, at that time, consisting of five, then entered upon their work; and, having first provided themselves with baked meat that they might not have occasion to leave the house, they worked incessantly till Christmas Eve, underpropping the walls, as they proceeded, with wood.

Presently the establishment of the merchants Birkin lay before us, an establishment of curious aspect, since it constituted, rather, a conglomeration of appendages to a main building of ground floor and attics, with four windows facing on to the street, and a series of underpropping annexes.