In a 2x10 floor joist, what is the maximum diameter of a bore placed 2 feet from the end?

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Multiple Choice

In a 2x10 floor joist, what is the maximum diameter of a bore placed 2 feet from the end?

Explanation:
Holes in floor joists are limited by the joist depth to keep the member strong. In structural lumber you can bore up to one-third of the joist depth, as long as you stay clear of the edges and ends. A 2x10 has an actual depth of about 9.25 inches. One-third of that is roughly 3.08 inches, so the largest bore you can safely place is about 3 inches. Being 2 feet from the end satisfies the spacing from the ends rule, so a 3-inch bore is allowed. Holes larger than that, such as 4 or 5 inches, would exceed the depth-based limit and weaken the joist. A 2-inch bore is permissible but not the maximum.

Holes in floor joists are limited by the joist depth to keep the member strong. In structural lumber you can bore up to one-third of the joist depth, as long as you stay clear of the edges and ends.

A 2x10 has an actual depth of about 9.25 inches. One-third of that is roughly 3.08 inches, so the largest bore you can safely place is about 3 inches. Being 2 feet from the end satisfies the spacing from the ends rule, so a 3-inch bore is allowed. Holes larger than that, such as 4 or 5 inches, would exceed the depth-based limit and weaken the joist. A 2-inch bore is permissible but not the maximum.

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