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walkereng, Consultant
Category: Structural Engineering
Satisfied Customers: 2599
Experience:  Over 30 years of Structural Engineering experience.
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I need to support a second floor with a 24-foot span on

Customer Question

hi! i need to support a second floor with a 24-foot span on the first one. What size/type beam can I use? It seems I only have about 7 or 8 inches in-between the floors, and I want the beam to be fully inside/recessed…
Submitted: 2 years ago.
Category: Structural Engineering
Customer: replied 2 years ago.
Joists of about 12 feet each are attached to this beam on each side along its length. They go from the beam to the house walls on the other side. The beam is therefore about in the middle on the house width. This current beam is an 8 by 8 inches square 22 feet long, made out of simple lumber. I feel I need a replacement of a stronger, non-bendable material… Please let me know if I am not asking this question fully, so I am aware of other important considerations. Thank you!
Expert:  StructuralEng replied 2 years ago.
You need a beam to span 24' and be 7" or 8" deep?
Customer: replied 2 years ago.
Yes, but it is 22 feet (please see additional information above), and the current one supports that 22-foot portion of the 55-foot-long second floor and a flat roof over the house with a wood deck on top. As also mentioned above, the house width is about 25 feet, and the beam is about in the center of it all, with joists attached to each side alongside it supporting the central portion of the second floor. The current plain-wood beam itself does not have any walls directly on it, but the joists attached to it support walls on the second floor rooms, etc. Please let me know what else can I provide for a good, detailed answer. I heard there are different materials that might be suitable (e.g., metal, composite), but I need a qualified and unbiased advice about whether to replace the current beam and which material would be good in this case and how to do it in the least expensive way without sacrificing safety. It is in California, so earthquakes are a concern and, therefore, structural safety.
Can you please also mention what are the pros and cons of just leaving the current wood beam alone? Some people are saying it will be sagging in a couple of years...
Expert:  StructuralEng replied 2 years ago.
I am skeptical that an 8" beam will work for what you want to do, but I will run the numbers.
Expert:  StructuralEng replied 2 years ago.
No standard 8" beam will work supporting a floor and roof with your span and tributary width.
If you need to stay within that depth, I can design a custom beam with an 8" depth as an additional service.
Customer: replied 2 years ago.
so, what kind of standard beam would support it, as result of the calculation you already did?
Expert:  StructuralEng replied 2 years ago.
I will tell you this answer as soon as I get home.