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Thread: Notching out a floor joist. HELP!

  1. #1
    guapoabeja
    Guest

    Notching out a floor joist. HELP!

    Ok so I have a vent that I would like to move and the only place to move it would require me to notch out 5 inches out of 2 2x12 that are like sister-ed floor joists. The joists that I would notch are under the main floor and run along side a stairway going into my basement.
    The whole purpose in this is to make a wall thinner. The problem is that everywhere that I have read say dont notch out a joist more then 1/4 of its depth and this notch would be almost 1/2.
    Soo the question is: is there some way to reinforce the joist so that a 5dx10w inch notch would be ok? I have thought about angle iron or a steel plate THEN doing the notches but I dont know! Advise?

  2. #2
    Technical Fellow
    Join Date
    Feb 2011
    Posts
    1,043
    Hi, the advice you have been given is poor at best, more likely stupid, than poor actually. You have no idea how close to the max limit that joist-pair are. They may be within 50-lbs of their design load. Notching out a quarter of the depth would pass it well into a dangerous area. The fact they are sister-ed also adds credence to the reality of high loads.

    You would need some steel cheek plates bolted through. Probably three with one squeezed up between the sister-ing if possible. Then all bolted through. The size and thickness of steel will depend on the max load the current full span calculates to, minus the losses of notch plus some safety factor.

    Best advice I can give you is to get an Engineer to do it for you. They will take things into consideration of say a refrigerator of 600-lb Armoires being moved across the floor above.

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