Wood

Wood is a time-honored construction material cherished for its beauty, aesthetics, and natural appeal. This segment introduces its extensive use in both temporary structures like formwork and scaffolding, and permanent applications such as floors, walls, and roofs. It covers two kinds of carpentry: rough carpentry, which involves framing and sheathing hidden within a building's finishes, and finish carpentry, which deals with visible decorative elements like trim, molding, and paneling.

Lumber is defined as processed wood less than 5 inches in its smallest dimension, while timber refers to wood members 5 inches or larger. The video explains the importance of pressure-treated wood for specific conditions, such as contact with masonry or concrete, and in situations where wood is at or below ground level. It discusses nominal versus actual lumber sizes, highlighting how dressing (S4S) affects the final dimensions and introduces the concept of board foot measurement.

This section introduces plywood and waferboard as common wood products used for subfloors, wall sheathing, and roof sheathing. Plywood is made from laminated wood veneers glued at right angles, while waferboard (also known as particleboard or OSB) consists of small wood fragments bound with adhesive. The video then transitions to typical residential framing, illustrating common components like beams, columns, trusses, rafters, studs, and various panels.

A detailed explanation of floor systems begins with floor beams or girders, which support the floor and roof loads. The video illustrates how these are carried and introduces foundation-seal plates as the first floor framing elements. It then focuses on floor joists, which carry the floor system, and highlights the role of joist headers in closing open ends. Bridging, such as solid or cross bridging, is discussed as a means to stiffen and brace joists.

Wall framing is broken down into exterior and interior components, including sole plates, studs, and top plates. The video demonstrates how to determine the number of studs needed and shows framing details for walls with doors and windows. It then moves to roof framing, contrasting stick-built rafters with pre-fabricated trusses. Key roof terminology like ridge, rafter, ceiling joist, span, run, rise, and slope are defined, emphasizing the support provided by rafters and the function of the ridge board.

Roof sheathing, which supports roof materials like shingles and tiles, is likened to subflooring in its calculation. The video then presents roof trusses as prefabricated frameworks of lumber, often 2x4s, connected with metal or gusset plates, offering a cheaper and faster assembly for roofs.

The concept of 'board foot' as a primary unit for measuring lumber volume is thoroughly explained. Despite the metric system, it remains common for commercial convenience. A board foot is equivalent to one square foot of 1-inch thick lumber (144 cubic inches). Formulas for calculating board feet for both rectangular and round lumber are provided, along with illustrative examples to demonstrate the computation process.

Finish carpentry, often handled by interior designers or architects, focuses on visible elements that enhance a building's beauty. This segment details exterior finish carpentry, including the installation of fascia boards, which close the open ends of rafters; soffits, typically made of exterior-grade plywood; and freeze boards, used as trim around buildings. Various types of exterior moldings, which must be exterior grade, are also presented as decorative items.

The final section covers interior finish carpentry, including interior trim such as wood-based moldings, chair rails, and crown molding, which are sold by length. Wood paneling, available in hardboard or plywood sheets and often pre-finished, is discussed as a way to enhance interior aesthetics. Lastly, architectural woodwork, including cabinets (often supplied by subcontractors) and miscellaneous wood ornaments like fireplace mantels, are mentioned as unique items that add character to a building's interior.