I am planning to build a utility building and am having difficulty with the roof design. The overall dimensions of the building are 12'W x 24'L. I was planning on doing a basic center beam and rafter roof with a 6:12 pitch as I live in a somewhat heavy snow area. Is there a way for me not to require a center beam support in the middle of the building? Or, is a standalone 24' roof beam sufficient?
I can help
Let me read your question a bit closer.
I can size a beam for you to clear span the 24' direction.
What city and state do you live in so I can check the code snow load?
spokane, wa 99206
I can look at an engineered timber beam or a steel beam, which do you prefer?
Let me run some numbers, hang on a few minutes
ok, thank you
Before we get started I’d like to point out that a Professional Engineer’s standard of care typically includes a site visit to assess field conditions and get an overall understanding of the structure. This can obviously not be accomplished through the internet. The information provided here is meant for planning purposes only (general sizing and budgeting) and is based on the information provided by you. All loading cases considered are for vertical loads only, no lateral analysis has been completed. The information should be verified by a professional engineer who can visit the site to ensure that potentially important information has not been overlooked or omitted.
The std minimum snow load in Spokane County is 30 psf, but it depends on your elevation and it can go up to 150 psf. Are you in the city or in the mountains?
outside of the city but not in the mountains. I think my required psf is 40 but I would like to get 50psf if possible
I will use a snow load of 50 psf. What is your roofing material, std asphalt shingles?
yes, asphalt shingles
OK< now I will run my numbers, hold on
I can give you a couple of engineered wood options for your beam:
5-1/4” x 16” Versa-Lam 2.0 3100 DF or SP
7” x 16” Versa-Lam 1.7 2650 DF
These are Boise Cascade products and you can go to the following link to find distributors in your area. http://www.bc.com/wood/ewp/distributors.html
You will need to have a local engineer detail your connections, size your support columns and determine foundation requirements.
This is for a ridge beam that is supported at its ends and spans 24'
ok, thank you for the information.
Good Luck with your project!
Over 27 years of Structural Engineering experience