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Old 11-05-2010, 10:33 AM   #1
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joist notches


when a joist is notched is the joist height reduced by the depth of the notch? is it true if the notches are at the very end tension side?

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Old 11-05-2010, 08:59 PM   #2
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joist notches


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Originally Posted by artmark View Post
when a joist is notched is the joist height reduced by the depth of the notch? is it true if the notches are at the very end tension side?
Why the theoretical questions?
If there's an issue, detail it.
Ron

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Old 11-05-2010, 09:23 PM   #3
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joist notches


I am curious a 25% notch is permitted at the end of a joist to sit on a ledger a 1/6 notch in the first and latter third I have a problem joist which may be way to difficult to repair, trying to understand if the code calls for a 2x10 joist knowing that it may measure 7.5 deep after being notched or ?
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Old 11-05-2010, 09:43 PM   #4
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joist notches


There is a difference in the load and stresses on joist. Each of the stresses have a different allowable stress.

Due to the normal distribution of floor loads, shear stresses are highest near the support and tensile or bending stresses are highest in the middle portion, so the area reduction and/or hole size varies with location depending on the code and type od joist material. Theoretically, shear stresses and compression perpendicular to the span are zero at mid-span. Conversely, the bending or tensile stresses parallel to the span are the maximum in the center portion and near zero at the bearing points. Since the aloowable stresses for shear and tensile/bending are different, the minimum joist depth is determined by the location along the length of a joist.

After all that technical B.S., the cutout depth or hole size generally depends on the location. Since the codes are a simplistic prescriptive standard they show the minimums, but a detailed analysis by an licensed engineer can over-ride a prescritive code minimum if you are willing the pay and engineer for a solution and absorb the liability.

Dick
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Old 11-05-2010, 10:27 PM   #5
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joist notches


ok then, if I am sistering a joist and need to notch the ends 1/4" to fit into exsisting framing and drill a hole as low as possible to the tension edge where do I measure from where the notch starts or the edge?
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