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Thread: Installing attic ladder - joists are overlapping

  1. #1

    Default Installing attic ladder - joists are overlapping

    We are installing an attic ladder above our garage. We need a rough opening of 22 1/2", but the ceiling joists are overlapping each other (side by side), so there is only 21" between the joists. Can we cut back part of one of the overlapping joist and add a sister joist to the other side? I am working on uploading a photo or sketch to more clearly illustrate, but if anyone has ideas in the meantime, that would be great. Thanks!

  2. #2
    Plumber jimbo's Avatar
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    You will need to head off the joist that you cut out.

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    Moderator & Master Plumber hj's Avatar
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    Are they just overlapping because it is a tail that projects past a bearing wall? If so, then the the piece may be redundant and can be cut off.

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    Aspiring Old Fart, EE, computer & networking geek Mikey's Avatar
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    Are all the joists like this, or did you just happen to find the one sistered-up pair in the ceiling?

  5. #5

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    Thanks for all the replies.

    All of the joists above the garage are overlapping exactly the same way. They are all 2x4 joists; the overlap is about 3 feet. Unfortunately, due to the slope of the roof, the only place that the ladder can go is right where the joists are overlapping.

    I've uploaded a diagram (just too darn hot to go up there and take a picture); I re-sized it so I could do the upload, sorry it is a little bit small.

    Thanks again!
    Attached Images Attached Images  

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    In the Trades AZ Contractor's Avatar
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    Is there a wall or header underneath where they are overlapping?

    Are they collar ties as well as ceilnig joists?

    Hard to see your picture, Can you cut out the white area more and enlarge the detail?

    Take a picture from below and draw on it where you want the opening then do the same from up above if you want accurate replies.

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    Aspiring Old Fart, EE, computer & networking geek Mikey's Avatar
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    Are these conventional joists or part of a truss system? What is the span? The reason I ask is -- if you're putting a stair in the ceiling it's because you want to get up there for some reason. If that reason is to put in a floor and store all your stuff up there, you may have a load problem with 2x4 "joists". Right now they may only be serving to hold the walls in from spreading from the rafter load, which is fine, and your proposed sister should do the job, but they may not support any floor loading above.

    http://www.youtube.com/watch?v=JLoge6QzcGY

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    Moderator & Master Plumber hj's Avatar
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    You don't show or tell why they are overlapping. Normally they would only overlap if there were a supporting wall somewhere under the overlap, unless they are acting as a tensioner between the outside walls.

  9. #9
    DIY Senior Member Livin4Real's Avatar
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    Hopefully smithx3 means "i-joist" instead of 2x4".
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