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I had an electric garage door opener "professionally" installed.

When seeing the installation, they mentioned they had to take a notch out of a supporting beam as there was not clearance for the train of the opener to run along the rail.

The beam itself is 3¾" by 1¾, with the notch being 3" long by 1" deep, so only 2¾" material remains where the notch was removed.

How would I reinforce this beam as it's supporting a platform above it and I'm hesitant to add weight to it?

There's not much clearance above the beam, perhaps 1".

https://photos.app.goo.gl/mVGxLNgFeqerFiZp8

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    That looks like standard dimensional lumber to me, not LVL (laminated veneer lumber). It'll have somewhat different strength properties.
    – Armand
    Commented Sep 21, 2022 at 3:14
  • Is something running on the top of that rail? Otherwise it looks like they removed so much more material than they needed to.
    – Spike
    Commented Sep 21, 2022 at 5:33
  • It may not be an LVL beam, in any case I think it's probably irrelevant to my question. A train for the garage door opener runs along the rail, which sticks up about 1/2" above the rail.
    – Matthew
    Commented Sep 21, 2022 at 13:03
  • I can't see your photos. Please embed one or two into your post rather than linking elsewhere.
    – isherwood
    Commented Sep 21, 2022 at 20:29

3 Answers 3

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I've heard a rule of thumb for comparative strength of beams is the square of the inverse. So in your case 3.75 squared is 14.06. It is now 2.75 so the new comparable strength is 7.56.

Now if you sister the entire member with another 2.75x1.75 then you'd hit comparable strength. Of course sistering a beam means glueing and fastening them together when the load has been removed.

A site visit from an engineer to approve a solution would likely be cheaper and easier than sistering the whole member.

I had a "professional" electrician's helper or maybe the electrician himself notch a 4" deep hole in the middle of a 18' 2x10 span. I had my engineer out and he specified a plywood girdle on each side of the notch maybe 4' long, ~2' on each side of the notch.

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  • +1 for the engineer site visit.
    – FreeMan
    Commented Sep 22, 2022 at 12:17
  • Thanks, the site visit seems the best option
    – Matthew
    Commented Sep 24, 2022 at 1:36
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There are all shapes and sizes of tie plates that you could attach to each side of the beam where it has been notched. Achieves the same end as sistering but with less material.

enter image description here

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  • Very true, but which one to select? Ah... that's where the engineer comes in handy!
    – FreeMan
    Commented Sep 22, 2022 at 12:16
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You’ll be guessing until you actually calculate the load. The Code requires attic space be designed to carry 20 psf (attics with storage ICC Table R301.5).

So after you add up the Live Load (you old photos, Christmas decorations that will be stored there, etc. plus the Dead Load (the actual weight of the lumber, plywood, roofing (if laying on the attic flooring), mechanical units, etc.), then you’ll know if the notch is acceptable. Then you can select the proper size connector, etc.

You may need an architect or structural engineer (not a civil engineer) to provide calculations so you can sleep at nights.

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