If after reviewing your foundation you have identified one or both of the deficiencies previously noted then we recommend that you retrofit your foundation. The retrofit will improve the seismic performance of your residence therby reducing the risk of damage during a moderate to strong earthquake.
The following are the structural upgrades that may be performed in one story residences and apartment buildings with a maximum of four dwelling units:
- The cripple walls shall be braced with 15/32 inch structural I plywood sheathing. The plywood sheathing shall be installed at each end and not less than 50% of the wall length. Individual panel lengths shall be two times the height of the cripple stud wall but not less than 4'-0". Minimum nailing shall be 8d @ 4" o.c. at sheathing edges. See details 1 and 2 below.
- Anchor the existing sill plate to the existing concrete foundation by installing 1/2" diameter bolts @ 32" o.c. The anchor bolts shall be embedded 4 1/2" minimum into the existing concrete with Covert cia-gel adhesive. See details 1 and 2 below.
