Proposed House Extension and Alteration

This project involves the structural design and engineering for the extension and alteration of a residential property. The comprehensive scope includes foundation details, floor and roof framing, and a robust lateral load-resisting system. The primary structural assembly utilizes C24 grade timber framing integrated with high-capacity Glulam beams to support the new house configuration. The foundation system features reinforced concrete basement retaining walls (designated RW-1 and RW-2) and a specialized foundation plan that accommodates both the existing ground floor and a new second-floor level. Floor framing is engineered with 47x150mm and 44x220mm C24 joists spaced at 400mm O.C., while the roof utilizes 35x195mm C24 rafters and glulam beams ranging up to 185x360mm. To ensure structural stability, the design incorporates a series of shear walls (A through F) and a detailed schedule of lintel beams (LB-1 through LB-5). The construction specifications mandate the use of Simpson Strong-Tie connectors (including HSS, RPS, and NS series) and stainless steel holding down straps to secure the timber frame to the substructure. Furthermore, the project specifies corrosion-resistant fixings and a strict site-fixing sequence to maintain the integrity of the timber-frame construction.

Role

Structural Engineer/Designer

Services Provided

The scope of services included the preparation of structural calculations and structural plans for the proposed structure. Structural calculations included loading analyses for wind, snow, dead, and live loads, together with the structural analysis and design of all primary structural components, including foundations, columns, beams, floor joists, walls, and roof rafters or trusses. The services also included the preparation of structural drawings consisting of the foundation plan, floor framing plan, roof framing plan, structural details, general structural notes and specifications, and a material list for the structural work to support construction and project coordination.