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Question
I want to put a patio roof on the back of my home. If I want to span 16 feet between posts is this possible. Can I use double 2 by 12s with plywood in between to make a beam? I am trying to eliminate a 3rd post to carry this beam.
Bob, you're pushing the envelope with just 2 2x12's. The plywood would certainly help if glued properly. Knee braces with substantial columns will also reduce the span. There is such a thing as as a flitch beam that uses a steel plate between the 2x's. YOu might also look into LVL which should get you there comfortably.
This gives you several avenues to consider. I think I would go with the LVL, it will probably be 14" deep, but please verify. It depends on how many square feet of roof load are involved, the dead loads, and wind and snow loads for your area. Here is some more information:
http://www.parr.com/PDFs/LP%20LVL%201.9E.pdf
I hope this gets you off to a good start.
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Answers by Expert:
Dan Griffin
Expertise
I can answer almost all questions related to the total construction process. My expertise is in commercial construction, though I can field most any residential question. I have hands on experience in concrete, heavy equipment, masonry, all phases of carpentry, interior finishes, and I am fairly strong in mechanical and electrical.
Experience
I have over 20 years experience as a commercial carpenter and commercial construction superintendent. I have another 20 years experience in facility management for a major school district.
Organizations
My favorite hobby for he past 12 years has been singing bass in a The OkChorale men's barbershop chorus and the Mature Moments quartet.
Education/Credentials
I hold a Bachelor's degree in English and Math. I have completed many continuing education hours in the building trades. I hold a Master Carpenter card from the AGC, Associated General Contractors.
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