around the beam merely moves the
point of condensation.
Rust can form and accumulate,
weakening the beam and creating
growing lumps of rust which force
themselves into and under the
surrounding materials with irresistible
force. Even without rust problems,
condensation can be a permanent
nuisance, as the water drips into
hidden construction or behind plaster.
Whether wood or steel, the beam
will be loaded and unloaded
periodically by people, snow and wind
loads. Its inside portion must be tied
down properly to avoid cracks which
open and close with the beam's
flexing.
Differential Vertical Shrinkage
As I have mentioned numerous
times in this column, it is important
to avoid large differences in vertical
shrinkage at various points in the
house, especially as the