12' and under 2" × 10" cross-bridged once.
12' to 15' 2" × 10" doubled every other one, if good stiffness
is desired, and bridged twice.
15' to 20' 3" × 12" and of long-leaf yellow pine, crowned at
centre ½", and bridged three times.
20' to 25' 3" × 14" of long-leaf yellow pine, crowned at the
centre 1" for the 25' spans, and bridged four times.
Floor-joists should be doubled around all openings larger than 3 feet,
and joists should be hung from the header beam by metal straps.
There are many precautions which should be taken to prevent the spread
of fire in the wooden frame house, but those will be considered as
a special subject. Likewise the discussion of certain defects of
construction which are commonly found in the speculative house will be
dealt with later.