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Adding Beam to Shore up Attic

4K views 10 replies 5 participants last post by  ron45 
#1 ·
My garage is ~28' deep by 21' wide. The attic has 2x8 joists that span the entire 21' and are 24' OC. Needless to say, they are rated to hold up drywall and barely at that! We had a structural engineer out to look at another issue in the house (it's in another thread of mine) and he also spec'd out a beam for the garage. I don't want a center post in the middle of the garage, but he said a W14x26 Ibeam or 7"x18" LVL would suffice to clear the span.

I'm leaning towards the Ibeam as it is cheaper, weighs less than the combined plies of the LVL and is narrower. Getting it installed maybe a bit more difficult, as it weighs just over 700lbs and is a single piece. The LVL would be easier as it'll come as 4 separate 1 3/4" wide pieces.

For support I'll remove the drywall on the ceiling to get right up against the joists and on the wall and the columns will be on the footers. I may have an easy way of getting the beam in by removing a few bottom pieces of aluminum siding and the sheathing between the garage doors and right where the beam should go. No lifting or wedging to get it into the wall cavity.

My question is the support columns, steel or 2x4's? Is it steel for the Ibeam and 2x4's for the LVL, or can you use 2x4's for the steel? From what I've read, the telescoping steel beams aren't code, or they have to at least be 3" in dia. Still reading on that one.

Not sure if this is something I'm going to try and tackle on my own or just hire out. But either way, want to make sure it gets done right.

Thanks,
HD
 
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#2 ·
Two people can lift up an LVL that long one at a time.
There's no way to remove aluminum siding in the middle of a row without damaging it, and it would be a nightmare to slide it in from outside like I think your suggesting.
If the LVL's are going to be stacked the supports need to be at least as wide as the thickness of the stacked LVL's.
The engineer should be telling you how the beam should be supported.
No way would I be using lolly columns.
 
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#4 ·
Thanks Joe. I'll double check with the engineer on the column requirements. As for the siding, I was planning on taking off just the bottom 3 rows of siding and sheathing to slide the beam into the garage. The beam will be going between two garage doors, so will have to deal with the vertical and horizontal garage door railing.
 
#3 ·
The engineer that specifies the beam should also specify the support for it. You also need to put new foundations in for the new supports to land on. The existing floor of the garage will not provide sufficient support.
 
#6 · (Edited)
that is a BIG steel beam

i did two w8x21 at 24 feet in my garage to hold up a second story addition. i put them both in myself (alone that is) using a genie lift....but they were only 500 pounds each

you would need 2 genie lifts (600# max)

its actually quite easy. but you have to lift in stages to get the beam on the reversed genie lift tongs (so you can get it flush with ceiling)...

so roll beam only lift (2x4 levers, and pvc pipe), lift to 3 ft, put cribbing under beam, lower lift and reverse tongs, lift to ceiling.

engineer specd teh columns....

never stand under an unsuported beam (you would be surpised how many people believe in a 1/4" steel cable


edit: btw, 26 x 28 = 728#. you wanna be specific with this job, lol
 
#9 ·
Thanks for the tips. I did manage to find a Genie lift with a 1000lb capacity at the local tool rental. Furniture dollies would be another way to maneuver the beam from the driveway into the garage.

The columns will be inside the wall cavity and let's say that is 28'. I'll need to have some room to move, say 1/2" off each end. That'll make the beam 27' 11". But finished wall to wall is going to be 27' 4". Swinging it in on the horizontal or lifting vertically maybe too tight. May need to mock up the beam with some 2x material and practice before ordering.
 
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