Saturday, March 23, 2024

Construction Project - Prep an I Beam

The deflection my 2nd floor joists meant that I needed to provide them some kind of support. The building codes and span tables only tell you the maximum span allowable for a given set of joist sizes and spacings. They don't say anything about how a floor should feel while walking on it.

I really didn't want to have to put a beam in - I've sistered joists, put in extra lvl beams, and put in longitudinal metal straping (like a suspender) along both sides of the doubled/tripled joists - but the sensation while walking on the second floor still wasn't right. 

I bought a 23 foot long W8x18; its 8" tall and weighs 18 pounds/ft.  I welded plates on the bottom of each end to facilitate bolting the columns to the beam, as well as welding short pieces of threaded rod so I can bolt a 2x4 wood nailing strip to the top of the beam. That lets me nail the joists to the top of the beam.

To raise it up, I will build 2 short walls on either side, and at each end, of the beam. Those walls can support a come along. I'll raise it slowly and block it off as I go up. Ultimately I can use two bottle jacks to finish putting it in position, then install the columns at each end.

Things, and attitudes, I learned more than 30(!) years ago make this possible.


At each end there is a continuous bead of weld on the underside of the plate.

Got it in with a little guidance from my neighbor

One of the columns will bear on the built up 2x12 beam at the top left of the above photo.  There is a window in the basement just below the position of that column requiring a much more substantial header, and there was no room to fit it above the window in the basement.  For the other end I'll have to put a small footing in the basement and bring a column up to the first floor level. A column on top of that will hold up that end of the beam.