Difficult to make suggestions on something of this nature without seeing it.
Our approach would be to remove all the bad wood or at least as much as we can. Anything remaining would be treated with the appropriate chemicals. Here you must be thorough to prevent further infestation.
Once repairs are made, you now need to focus on the cause of the problem. Again, not seeing what you have there makes it difficult to advise on this.
Since you are dealing with structural members I strongly advise you to consult a professional.
Let us know your progress
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Bart Blainey, B.E.R.
Consultant/Journeyman Carpenter
Building Envelope Specialist
Master Renovator
provip@prodeck.org
http://www.prodeck.org
Barton Blainey (provip) specifically assumes no legal liability or responsibility for the accuracy, completeness or usefulness of any information or process disclosed. The above further expressly advises that any use of or reliance upon the information and or opinion disclosed is at your risk .
_________________________
Bart Blainey, B.E.R.
Consultant/Journeyman Carpenter
Building Envelope Specialist
Master Renovator
provip@prodeck.org
http://www.prodeck.orgBarton Blainey (provip) specifically assumes no legal liability or responsibility for the accuracy, completeness or usefulness of any information or process disclosed. The above further expressly advises that any use of or reliance upon the information and or opinion disclosed is at your risk .