03-01-2014, 03:33 AM
When pinning to rock (any rock) for foundation purposes, it is common to anchor at a 24" depth.
The reason for this is stress fracturing when under seismic load, which when occurring with a shallow set anchor leaves the home with very little mass under foot. The 16" recommendation is a compromise to the 24" rule.
The reason for this is stress fracturing when under seismic load, which when occurring with a shallow set anchor leaves the home with very little mass under foot. The 16" recommendation is a compromise to the 24" rule.