4704 HARBOR LN 2018-01-02 MF Import

Foundation Remediation Recommendations It should be understood that our recommendations are not meant to stabilize against future slope -related earth movement, but will provide foundation support equivalent to what was provided before damage to the foundations occurred. Development of the site should proceed only with Pemco's and the homeowner's understanding and acceptance that our foundation remediation recommendations do not mitigate the pre-existing geologic hazards associated with this site. Two isolated footing units in the southern portion of the house have been undercut by erosion. The undercut portions of the footings have voids below the bottom of the footing, extending as much as 8 inches deep. These footings can be remediated by sev^ral methods, including pipe pile underpinning, partial excavation and backfill with controlled density fill (CDF), or re - supporting the undercut portions with a footing extension. For tht: underpinning option, the existing floor would have to be removed to expose the crawl space area and provide worker and equipment access. Underpinning would be highly destructive to the interior of the house and is therefore not recommended. Similar constraints exist for excavation and replacement with CDF, as portions of the crawl -space area below the house are less than 18 inches in height, making digging and filling very difficult. It is AESI's opinion an effective and less intrusive method would be to re -support the footings by adding an extension to each footing unit. In general, the footing extensions can be constructed in the following manner • Remove any loose or disturbed soils from new foundation areas to the satisfaction of the geotechnical engiteer. • Install dowels to mechanically connect the new extension to existing foundations, as recommended by the structural engineer. • Place forms around new foundation areas. • Place internal (rebar) reinforcement, as recommended by the structural engineer. • Pump grout into new foundation extension areas. A structural engineer will be required to determine the required size of the extensions and the reinforcing details. We recommend that the footprint of the damaged foundations be increased so as to distribute the footing load over a greater area. The footings with the extensions should be designed such that the total foundation footprint has a maximum allowable bearing pressure of 1,000 pounds per square foot (psf). 3 3(v