Home Improvement--General/broken beam.
QUESTION: Someone previously installed a garage door opener and cut a notch in the door header beam almost in half. It is a 4x14 solid beam spanning about 17 feet end to end. The beam of course has split and has a crack heading back about 2 feet on one side, and about a 2-3 inch drop. A slight sag is visible in the roof. The 'unsplit' side has dropped about an inch.
There will be about 6 1/2 inches above the door opener trolley once I adequately support the trusses.
I have two ideas. I can install a steel beam alongside the wood beam to support the roof trusses that rest on this beam.
It is a low pitch cedar shake roof on a solid roof deck of 1x6 boards. Question- will a w6x25 I-beam be strong enough? I plan to leave the wood beam in place and install a couple of threaded rods to pull the 'split' back together, and probably on the unsplit side as well.
My other idea is to have a steel plate made for each side of the existing beam. But even then I really only have the 6+ inches of space.
Would two 3/8" or even 1/2" thick steel plates, one on each side of the beam, 6 inches by 17 feet bolted to/through the wooden beam be an acceptable fix? This would be easier for me than a single steel beam. I have a bad back, and need to do this myself for financial reasons(poor), so cost is a HUGE consideration.
Thank you so much.
ANSWER: 1st you need to install a post jack or jacks and stop the downward failure of the beam.
You are describing a progressive failure that could be catastrophic (complete collapse) at any time.
I cannot give you a detailed response without doing field observations and calculations.
You will need to find a local engineer to evaluate your loads and detail a solution.
Conceptually the idea of a side plate or plates is not wrong but how it is implemented is critical.
I am GUESSING steel plate(s) will be the direction taken.
The thickness of the steel may be less and area different. Wood failure and connection shear will be issues to figure out.
Support the beam NOW.
---------- FOLLOW-UP ----------
QUESTION: Thanks for your quick reply. The beam has been that way for at least the 10 years I have been here, probably since the opener was installed. I am aware that it could fail at any time, but c'est la vie. Generally though- Is a w6x25 steel beam the same strength as the original 4x12(corrected) wood doug fir beam over a 17 foot span??
There is no generally with engineering. That is why observing the site conditions is important.
You will need to get someone local to give you specific answers.
You can also consider installing a tension plate on the bottom edge of the beam to compensate for the lost tension due to the cut.