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StructuralEng
StructuralEng, Bachelor's Degree
Category: Engineering
Satisfied Customers: 7014
Experience:  Engineering Expert
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Shoring/support question - a 6 foot bump out section in my

Customer Question

Shoring/support question - a 6 foot bump out section in my house only has a crawlspace foundation. The rest of the house has a full basement. I would like to excavate the crawl space to create full basement. The width of the bump out is about 10'. If I place 3 2x12 under and through the bump out along its width, would that suffice for support whilst I excavate underneath
Submitted: 1 year ago.
Category: Engineering
Expert:  StructuralEng replied 1 year ago.
Do you have a sketch or picture you can post?
Customer: replied 1 year ago.

I am sorry I do not. Let me clarify a little more. There is a bump out on the house that extends 6'. Its width is 10' so the bump out is 10x6. It was built with a crawl space foundation however the rest of the house was built with a full basement foundation. I would like to excavate below the bump out without tearing out the bump out.

Expert:  StructuralEng replied 1 year ago.
So where would the triple 2x10 go?
Customer: replied 1 year ago.

Under the bump out from end to end so across the 10' width.

Expert:  StructuralEng replied 1 year ago.
But if you're digging underneath it, what is going to support it?
Customer: replied 1 year ago.

The length of the 2x12 are going to be longer than the width of the bump out so the ends will rest on firm concrete or 4x4's. Once I have finished the dig, I will pour concrete walls around the perimeter

Expert:  StructuralEng replied 1 year ago.
What will be the span of the triple 2x10? Is it supporting one floor or two along with the attic and roof?
Customer: replied 1 year ago.

I don't know what the span should be. That is why I am asking. It is supporting two floors and the roof of those two floors

Expert:  StructuralEng replied 1 year ago.
I can size the beam, but I don't have enough information to tell you how far out to take it. Unfortunately, I need that information to size the beam. I can say that a triple 2x10 is not likely to work.
Customer: replied 1 year ago.

What other information do you need to know what will work?

Expert:  StructuralEng replied 1 year ago.
The length of the shoring beam and the length of the joists supported by the beam.
Customer: replied 1 year ago.

Could you tell me what would work? Nothing has been purchased yet

Expert:  StructuralEng replied 1 year ago.
I need the information above first.
Customer: replied 1 year ago.

The information you requested is the length of the shoring beam and the length of the joist, correct? No shoring beams and no joists have been purchased therefore I am asking what sizes would work

Expert:  StructuralEng replied 1 year ago.
The joist lengths of the existing structure, since that is what you're shoring. With the miscommunication, I'm really not comfortable proceeding without a sketch