Retaining wall query

In order to use the existing 4’ retaining wall for new deck area and support of portable spa, either a complete engineering analysis will be needed from a structural engineer to verify that the existing wall will handle all applicable proposed new loads or a new engineered retaining wall and permit will need to be created that accommodates the new deck area (This is for the existing retaining wall and not the proposed new retaining wall that will be interfacing with the slope area.) This engineering will be separate from any pool engineering that is already provided and will be specific to the existing retaining wall and the loads that will be created above it. (A letter from the engineer of record for this project is necessary to verify whether or not the existing permitted retaining wall can be used for the new deck with spa.)