Installing Stiffening Beam And Support Columns

ahsllc

I have a NJ customer in a townhouse in which the engineered wood I beams that support the living room need to be stiffened (too much bounce in the floor). An engineer suggested 3 microlam beams fastened together supported by two 4 inch lally columns. My question is if the columns are not technically load bearing (installed only to stiffen the floor) can they be placed directly on the slab without cutting, digging and pouring proper load bearing footings and still be within code?

Any suggestions would be appreciated.

Brock

Nope. Once you touch it, you are responsible to bring it all up to current codes.


Unless ofcourse you can get a stamp from the structural engineer to overwrite it. That always overrides the inspection results.

neolitic

It's probably not drastic enough
to suit an engineer, but have you
thought about a row or two of
western bridging?
Assuming the joist aren't over spanned,
they my simply be under bridged.

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rbsremodeling

I can't tell you how many homes I go into with springy floors that just need some damn blocking. Makes no sense. They probably through away enough scrap to do it with

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dkillianjr

Hey neo, I have never heard the term western bridging. Is that just regular solid blocking?


Dave

rbsremodeling

Solid blocking but you have to do it wearing cowboy boots and hat


Playing the theme from broke back mountain of course on your ipod

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neolitic

Don't got no eye-pods,
only one Larry McMurtry movie
that I've never seen.
0 for 2!

Western bridging is usually 1X3's.
It's installed so that it looks like
an "X" when one looks down the
joist bay.
It'll do everything that block bridging
does, plus allows room for plumbing,
wiring, etc...

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dkillianjr

Thats what I thought rbs maybe that would be a good time to break out the john wayne signiture series framing nailer!


Dave

dkillianjr

O ok thanks neo yeeha


Dave

neolitic

You have seen it, right?



The bridging that is, not the movie.

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rbsremodeling

Yeah alot of the older homes have it I use to put in regular blocking and install western blocking where the plumbing and electrical lines have to go.

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dkillianjr

O heck ya the wood x, metal x, and solid blocking I just didn't know any of it had different names.


Dave

KentWhitten

I have always told people that the formula for FJ spans is flawed, especially with TJI's. The longer the span, the more deflection it has. Even though it is still to code under the L/360 or 480 or whatever it's designed for, the TJI's that can span greater lengths are the bounciest of them all.

You really have to increase the deflection denominator if you want a stiffer floor.

The stiffest floor I ever framed used 2x6's over a crawlspace. Beams from my recollection were 7 or 8' apart. There was hardly any deflection which made it super stiff. My initial reaction was "who the hell would do this?" After I finished the plywood decking, I was convinced (and schooled) that shorter distances between supports is cheaper and stiffer.

Builder saved himself over $1000 from what he told me. Not really feasible in a basement situation, just crawlspace.

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DrewD

That really goes without saying, the shorter the span the stiffer the joist. Recently I reinforced the floor system at my grandparents house, laminated steel plates to both sides of the main beam with through bolting staggered every 12" O.C. top to bottom. Next I doubled up every other floor joist and added bridging (there was none). We had the floor tore up so I added a layer of 5/8" subfloor glued and screwed. There was only one layer of 5/8" intially so now I have 1 1/4". After I was all done I believe you could park a truck on that floor.