1-9. Girder Supports. When small houses are built without an architect, the carpenter must know
the principles that determine the proper size of girder supports.
a. Columns. A vertical member, designed to carry the live and dead loads placed upon it is
called a column or a post. It can be made of wood, metal, or masonry. Wooden columns may be solid
timbers or several wooden members nailed together with 16d or 20d common nails. Metal columns are
made of heavy pipe, large steel angles, or I-beams.
b. Column Spacing. A good arrangement of the girder and supporting columns for a 24-foot by
40-foot building is shown in Figure 1-14. Column B will support one half of the girder load existing in
the part the building lying between wall A and column C. Column C will support half of the girder load
between columns B and D. Likewise, column D will share the girder loads equally with column C and
wall E.
Figure 1-14. Girder and column spacing
NOTE: When locating columns which must support girders, avoid spans of more than 10 feet
between columns. The farther apart columns are spaced, the heavier the girder must be to carry the
joist over the span between the columns.
c. Bearing Plates and Footings. Regardless of the material used in a column, it must have some
form of a bearing plate at the top and bottom. These plates distribute the load evenly across the
column. Basement posts that support girders should be set on masonry footings. Columns should be
securely fastened at the top to the load-bearing member and at the bottom to the footing on which they
rest.
1-11
EN5156
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