Structural Foundation and Roof Plans

Foundation and Roof Plans

Structural Foundation Design

A foundation in residential construction may consist of a footing, wall, slab, pier, pile, or a combination of these elements. The most common residential foundation materials are concrete masonry (i.e., concrete block) and cast-in-place concrete. Concrete slabs on grade are the most popular foundation type in the southeast, while basements are common in the east and midwest, crawlspaces in the northwest and southeast, and pile foundations are used in coastal flood zones, weak or expansive soils, and steeply sloped sites.

Footings

Footings support the weight of a building's structural components by transferring the loads to the soil beneath them. The size of footings depends on factors such as soil conditions, wind load, snow load, and seismic activity. In regions with high fire risk, masonry footings may be required for added safety against flying embers.

Roof Framing

Roof framing provides the structure that supports roof decks, roof coverings, and other elements, connecting rafters from the top beam (ridge) or hip to external wall plates. There are two main methods of roof framing: stick framing and truss framing. Stick framing uses individual rafters connected to the top beam, providing flexibility for later changes to space or structure when needed. Truss framing, on the other hand, constructs gable and hip roofs using prefabricated trusses designed according to specific architectural requirements.

Stick Framing

In stick framing, the top beam is the central element connected to individual rafters through additional horizontal boards, providing a foundation for covering the entire structure. This method is suitable for buildings with cathedral ceilings, attic rooms, or areas for storage, where an open triangle shape between ceiling joists and rafters can be easily manipulated if necessary.

Truss Framing

Truss framing involves constructing roofs using gable and hip roofs made from prefabricated trusses. They offer advantages like reduced construction time compared to stick framing due to their modular design and precision. However, truss framing may not be suitable for all designs; consultation with professionals is advisable for specific situations.

Roof Types

Flat Roofs

Flat roofs require waterproofing at the substrate level, often covered with materials like bitumen felt, single-ply membranes, or built-up roofing. Waterproofing solutions designed to allow multiple finished effects after installation or remain exposed are available.

Pitched Roofs

Pitched roofs come in various styles and slopes, including gable, hip, and combination designs. Gable roofs have triangular sides meeting at the top with two sloping planes forming a peak. Hip roofs feature four faces sloping downwards from the centerline, creating a gentle curve. Combination roofs often blend both gable and hip components.