A space must be left in the walls for the doors and windows. This is
done by placing between the wall forms, frames or boxes without top or
bottom made of 1-inch boards. When the wall form has been filled to
the level of the bottom of the opening a frame, the size and shape of
the opening desired is secured firmly in place and the concrete poured
around it. After the wall reaches a level 2 inches above the frame lay
in the fresh concrete two ½-inch iron bars. These pieces should be long
enough to extend 8 inches beyond each side of the frame. A piece of old
wagon tire can be used instead.
The sill shown in the sketch can be molded by building a small box
extending out from the side form. The concrete should be placed for the
sill at the same time that the wall is being built. For buildings such
as we have mentioned a sill is unnecessary.