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Old 04-14-2014, 03:31 AM   #1
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Help me understand how joists work

Hello All,

While investigating the possibility of opening a load bearing wall to open up my enclosed first floor steps, I took to the basement to see the current setup downstairs.

I found the in the area of the steps, where the floor joists cant make the span from each side of the foundation (or you would walk into them on the steps), they are nailed to a double 2x8 header.

I did a bit of research, and this seems like its acceptable. However, I simply dont understand how this engineering works.

Wouldn't the downward force on these beams cause them to break away from the 2x8? I can't imagine that the few nails holding them in have much strength value.

Why wouldn't the beam be placed under the joists to account for this downward force, and then a support column placed on either side?

I attached a few photos to try to explain my questions.

Thanks in advance for the help in understanding.


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Old 04-14-2014, 05:16 AM   #2
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Can't see any pics?


tony.g is offline   Reply With Quote
Old 04-14-2014, 10:23 AM   #3
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I see one photo. Seems like a compromise. How many joists were cut short like that?
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Old 04-14-2014, 10:48 AM   #4
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That isn't really a beam.

Its a reinforced box out to support an opening for the stair framing.

Notice how the beam doesn't extend all the way to the bearing wall.

When an opening is created in framing system, multiple joists are cut short to facilitate the opening. As such, the edge of the box picking up the load of all of the abbreviated joists is typically doubled up.

If it was a true beam, it would extend to the bearing point on each end which it doesn't.
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