As we built up the brick envelope around the window and door openings, we installed lintels above each opening. These will serve not only as trims or casing for the top part of each opening but also as a support on which the next row of bricks will rest. Using one solid piece of wood for this operation was not an option given the width and depth of the openings. We opted for building the lintels and casings out of an assembly of planks and small beams.