Structural Ridge Beam Size
Structural Ridge Beam Size
(OP)
I am building a home in West Virginia. The design is cross gabled,i.e., the center section has a perpendicular section on each side. The center section is a 6/12 pitch. I am using 2x12 rafters on a 45 foot ridge beam. The dl=15psf, ll=40psf. What size ridge beam(LVL?GLULAM?MICROLAM?) do I need? Thanks
Jack
Jack






RE: Structural Ridge Beam Size
1. If you design the ridge beam as a "true ridge beam it will take 1/2 of the entire roof load. If there are no interior posts it becomes a very large ridge beam with a 45 ft span. The purpose for putting in a heavy ridge beam is to take out the horizontal component from having opposed rafters meeting at the ridge that tend to push the walls out when they are loaded.
2. The valley rafters and cross ridge beam for the gables also put large concentrated loads at the center so that the load on your ridg beam is not uniform.
3. For a 45 ft long ridge beam with no interior supports the end column become very critical because of the long columns and high loads.
4. The connections of the ridge to the columns can become critical looking at uplift from wind especially if you have long overhangs or wings at your gables.
In short, hiring a local licensed engineer to ensure that your largest investment "your house" does not come crashing down around your knees in the first really heavy snow or wind is a small price compared to the risk. There are many simple wrong answers to simple looking complex problems.
RE: Structural Ridge Beam Size
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Structural Ridge Beam Size
for exasmple
If you are talking a true ridge beam spanning 45' if the width is only 10'
you would need 5- 1.75"x18" deep microlams
RE: Structural Ridge Beam Size