For residential living-area floor framing eligible for the conventional provisions of 2021 IBC Section 2308, use Table 2308.4.2.1(2) with 40 psf live load and an L/360 deflection limit. No. 2 Douglas Fir-Larch 2x10 joists are spaced 16 inches on center, with 10 psf dead load. What is the tabulated maximum span?
- A12 feet 7 inches
- B14 feet 1 inch
- 15 feet 5 inches
- D17 feet 10 inches
Where to look it up
https://core-docs.s3.amazonaws.com/documents/asset/uploaded_file/3836/Lennox/3042180/2021_International_Building_Code.pdf
Why C is correct
The 16-inch-spacing, No. 2 Douglas Fir-Larch row and 10-psf-dead-load 2x10 column give 15 feet 5 inches. This is an allowable maximum, not a minimum span. Spacing alone cannot establish it. Source: 2021 IBC 2308.4.2.1 and Table 2308.4.2.1(2), p. 23-38; https://core-docs.s3.amazonaws.com/documents/asset/uploaded_file/3836/Lennox/3042180/2021_International_Building_Code.pdf