Your feature article on foundation anchoring and seismic retrofitting of the under floor space in homes ("Bracing for the Next One," March 13) was excellent in that the repair cost is very nominal and retrofitting is extremely beneficial. All houses should be properly anchored to reduce seismic damage. Arbitrary rules on percentages of perimeter wall length to be sheathed are hard to justify and should be based upon the type of house, the house configuration, etc.
The article indicates it is not necessary to brace interior walls. In my opinion, this is very unwise recommendation, because in many houses, the interior walls may have twice the seismic force of an exterior wall. All houses should be reviewed by an experienced engineer who can direct the contractor to do an appropriate job. Home videos are great but seismic retrofitting is an investment in one's home that should be reserved for the professionals.