Horizontal Addition and Interior Remodel

Project Details

This project involves the structural design and engineering for a horizontal addition and comprehensive interior remodel of a two-story residential building. The engineering scope required modern structural solutions for the entire assembly, including the design of wood beams, columns, header beams, and load-bearing walls. The primary structure utilizes Douglas Fir Larch No. 1 and No. 2 framing integrated with Structural-I plywood sheathing and high-strength metal connectors. The design process included a rigorous structural analysis to ensure the building could safely withstand environmental loads in accordance with the International Building Code (IBC 2021), the 2022 California Building Code (CBC), and ASCE 7-16 provisions. Special attention was given to lateral load resistance for a high-seismic region, classified under Seismic Design Category E, with a design response factor of R=6.5. The structure was also engineered to withstand wind speeds of 92 MPH. Stability is provided through a segmented shear wall system utilizing specific nailing patterns and heavy-duty hold-down anchors. The foundation system features independent reinforced concrete pad footings (1.5′ x 1.5′ x 12″) designed to perform reliably under a soil bearing capacity of 1,500 psf.

Role

Structural Engineer/Designer

Services Provided

The scope of services included the review of the existing structural system to evaluate gravity and lateral load paths based on the approved structural drawings and available documentation. The work involved assessing proposed interior wall removals to determine whether affected walls were load-bearing and evaluating the impact of the modifications on the overall structural performance of the building. Structural calculations were performed to design required beams, headers, posts, and supporting elements necessary to safely redistribute loads resulting from the removal or alteration of existing walls. The analysis also verified that the proposed modifications did not adversely affect the existing lateral force-resisting system and maintained a continuous and code-compliant load path.
The services further included the preparation of structural drawings for the remodel scope. The drawings incorporated demolition support notes and temporary structural recommendations where required during construction, together with revised framing plans for the affected areas. Structural plans identified the locations and sizes of new beams, posts, and related framing components, and included connection details associated with removed or modified walls. Structural notes and specifications applicable to the renovation work were provided to facilitate plan review, coordination, permitting, and construction implementation.