Interior Walls. Fig. 119 illustrates the construction of a corner of an interior wall which is to be recommended highly for strength. All door studding are to be doubled for strength, also window openings of unusual size.

Interior door jambs are not usually placed until after plastering has been done. Thresholds are no longer used with interior openings where both rooms are to be heated.

Joists doubled to support partitions should be spread sufficiently to allow furnace pipes to enter, and still provide bearing for partition studs.

Badly crooked studs in a partition wall may be straightened by sawing a kerf on the hollow side, almost thru, and wedging with a shingle point. A cleat nailed to the side of the stud after wedging will give the original strength. Straight studs should be selected for use about openings.

In setting studs for interior door jambs where studs are to be doubled on the inside, add to the width of door enough to make the outer edges of the casings center on studs, and double inside these, as in figuring openings between studs for outside door jambs. Make allowance for the extra thickness of stud on each side. For height of opening, where no threshold is to be used, add 2" to the height of the door. Remember that enough more must be cut from vertical studs to allow for thickness of header.