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walkereng, Consultant
Category: Structural Engineering
Satisfied Customers: 2571
Experience:  Over 30 years of Structural Engineering experience.
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I am building a roof over my patio. The patio is 14' out

Customer Question

I am building a roof over my patio. The patio is 14' out from the house and I want a 3/12 pitch on the roof. The patio is 25'-5" long. I will have 4 post across the front edge of the patio, the span of each beam will be 8'-6". I believe I can do the rafters with 2x8's at 24" o.c., Fb=1100 Hem Fir, and the beams caring the roof load (2) 2x8's glued and nailed. I'm I correct? Thank you.
JA: OK. Is there anything else important you think the Structural Engineer should know?
Customer: I am designing the roof with a 30 lb live load and a 15 lb dead load, and a deflection 1/240 I planning to have a tongue and grooved ceiling.
Submitted: 4 months ago.
Category: Structural Engineering
Expert:  StructuralEng replied 4 months ago.
Hello. I can help.
Expert:  StructuralEng replied 4 months ago.
Where did you get Fb=1100 psi for hem fir in an exterior environment?
Customer: replied 4 months ago.
I believe that is the typical fiber bending stress of lumber in my area, Northeast Ohio, from any dyi center? I am not quite sure if I need to use treated wood which would be Yellow Pine, probably No2 which would be a lot stronger.
Expert:  StructuralEng replied 4 months ago.
The basic Fb for hem fir no. 2 is 850 psi, not 1100. When you adjust for size, load duration, and moisture conditions, you will get something different, but it starts at 850, not 1100
Customer: replied 4 months ago.
If you can't give me an answer, please refund my $5.00. I will find the answer to my question elsewhere.
Expert:  StructuralEng replied 4 months ago.
I can give you an answer. I was trying to help you understand. I'm going to opt out for you.
Customer: replied 4 months ago.
Am I being charged $31.00 for this info? I thought it was free for the first month. If so do not answer my question and refund my money and opt me out of your site.
Expert:  StructuralEng replied 4 months ago.

You haven't been charged anything yet. I'll be happy to request a refund for you. I apologize, but I prefer not to deal with that type of attitude when I'm attempting to provide information that will be different than what you're assuming. I will request your refund. Good luck with your project.