In ordinary wood-frame construction, wood floors are typically supported by

• A. Beams
• B. Joists
• C. Piers
• D. Columns

Answer: (B)

The main concept is how floor framing carries load in ordinary wood-frame construction: the floor surface is carried by floor joists. These horizontal members run between bearing points such as walls or beams and support the floor sheathing and loads from above. The joists transfer those loads to the beams or bearing walls, which then carry them down to the foundation. Beams do support the joists, but the direct support of the floor deck itself comes from the joists. Piers and columns are vertical supports that transfer loads to the foundation, not the primary means by which the floor surface is supported in typical residential framing.