Sistering a Wood Beam with Steel


Old 12-07-04, 05:36 PM
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Sistering a Wood Beam with Steel

I'm removing a support post from under a 6 x 8 beam and am going to sister the with steel angle to reinforce it. A structrucal engineer calculated that I could span the 14' with two pieces of steel angle sistered to the beam. My question is how to best sister them to the beam? Just through-bolt them? If so, how often and with what diameter hardware? This still won't leave the ends of the steel angle supported on the posts.

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Old 12-07-04, 09:54 PM
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Hi Mark & welcome to the forums. Bolting completely thru the beam & both angles about every 12" to 16", with like say a 1/2" bolt should do the trick I'd say. Not quite sure what you mean by "still won't leave the ends of the steel angle supported on the posts."
Old 12-07-04, 11:21 PM
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Those sound like good questions for the structural engineer.
Old 12-08-04, 05:52 PM
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Cannot Drill Through a Beam

Building Codes prohibit the drilling, notching and boring of any structural beam within any home.

The engineer may have casually mentioned the use of angled steel to support the beam, but you had better get clear instructions from him AND your local code office before you do anything to the existing beam.

I'll presume that you have simply misundertsood the structural engineer's instructions at this point.

Major structural alterations such as your proposed undertaking are NOT a DIY project.
Old 12-08-04, 07:11 PM
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Someone led me to a 'flitch plate' design elsewhere. You sister steel plates on the sides of the joist by through-bolting. The seems to be a very common way to increase the deflection stength of a beam when removing a support. I'm not sure about my local codes, but I read discussions by building inspectors in regard to flitch plates and they never mention the bolting as a concern. There's a great PDF on the subject at;

Thanks everyone.

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