- Q.I am working on an old oak
timber-frame house which has been infested with
powder-post beetles. The exterminators say the beetles
are gone. How can I test the extent of the damage to
the beams?
A.There is no
practical nondestructive test for the strength of
wood that is already in a structure.
The damage must be evaluated on a case-by-case
basis. In general, if the damage is in an area
where the primary load is in bending, there must be
enough undamaged wood at the top and bottom of the
beam to withstand tension and compression, and
enough in the center to withstand the horizontal
shear. If the damage is near the beam ends, there
must be enough undamaged wood to provide
bearing.
The only safe thing to do is to reinforce the
infested members so that you are not depending upon
their original strength.