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After finally completing the addition and building a few other projects, it seems the time is right to build a shop in the basement beneath the family room to store the leftovers. But I need to remove a column in the middle of this floor. There are no supporting walls on the floor above the basement. The floor (plywood subfloor, 1/4" Hardy board underlayment, Doug fir flooring + radiant heat tubing) is supported by simple construction 2x10 floor joists hung off three sistered 1 3/4 x 9 1/2 microlam beams. One end of the carrying beam is on the sill, the other on a column where it meets the chimney. It cannot be lifted without risk to the granite hearth above this end. A third column, the one to be removed, is in the middle. The combined floor expanse of 2x10's is 24' and the support beam itself is 15' long. There is a good chance the center microlam of the three is actually two parts laid end to end at the center column, while the outer microlams are continuous. I want to through bolt the three microlams along the middle third of the 9 1/2 width in each bay. It cannot be sistered due to the joist hangers as described. The table saw has to live somewhere! I have tried the tables and not sure I am reading them right. It appears three 9 1/2's is marginal at 12' let alone 15'. I could add a short knee at either end to reduce the length to 9' but would rather not. Is there a knee that attaches to a lolly column? Can I get away with just through bolting?
 

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No, the spacing of the lolly columns was specified by the manufacturer of the beam based on the calculated loads of the structure.
 

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Agreed, you cannot remove or re-locate the column without completely replacing the beam with a larger one that can make the span.

A structural engineer should be brought in to evaluate the situation and make recommendations. Without a much more substantial beam I assure you removal of the column won't be a good idea.
 

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Wow, really? There was no structural engineer involved. Just a local crew of construction guys with common knowledge. There is no spring in the floor, quite rigid and no dead load or bearing wall. A triple 1 3/4 x 9 1/2 rates a 12' span if I'm reading the table right. You don't think I could knee brace the ends and drop the 15' span to 10' and through bolt it?
 

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I didn't have a structural engineer involved when I built my 3 story 24x36 additon
2 LVL beams are "only" supporting the floor above
But I still can't remove the support columns I installed

You have 2x10's spanning 24' ?? ......or they rest on this beam ?
 

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Wow, really? There was no structural engineer involved. Just a local crew of construction guys with common knowledge. There is no spring in the floor, quite rigid and no dead load or bearing wall. A triple 1 3/4 x 9 1/2 rates a 12' span if I'm reading the table right. You don't think I could knee brace the ends and drop the 15' span to 10' and through bolt it?
Either the plans had the specifications listed in them or the contractor supplied the information to the beam manufacturer and they engineered the beam and the column spacing. Usually there is a set of plans specific to the beam, columns, and column footer location. These would also specify nailing and bolting patterns.
 

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"There is a good chance the center microlam of the three is actually two parts laid end to end at the center column, while the outer microlams are continuous." --------- these are rated by the builder/engineer for their specific load required. If as you say, "A third column, the one to be removed, is in the middle." ----- You would only have two carrying one, not three. You NEED three. You would then be over-loaded by 1.43 times.

Full length, not pieces. Even if all three are full length, do you think the builder added the post in the middle because: 1. he had an extra post and concrete footing for it, 2. he thought someone may want to remove it later, 3. he wanted to spend more money on post and concrete and labor to reduce his profit on the sale? Please do not remove it as these are rated for the existing spans and loads.
Dave: "I didn't have a structural engineer involved when I built my 3 story 24x36 additon" you did tell us before the lumberyard sent your plans out to be checked, correct? Who do you think checked them? For a yard to take the responsibility for the structural integrity and worthyness of a building, I doubt the counter-person's wife checked your plans.....

"You don't think I could knee brace the ends and drop the 15' span to 10' and through bolt it?" ---- No, that's not how it works, sorry. In my 36 years of framing, I've yet to see that. Just through bolting will not work either, unless a S.E. could prove me wrong. You would be holding up over 9000# here, not something to take lightly.
Be safe, Gary
 

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i'd rather work in a shop than wear it :furious: but its your shop so it may fit better,,, i'd, personally, not want to hear my insurance company laugh then deny any claim,,, installing columns to straighten out your sagging roof's not fun, either.
 

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No

NO:thumbdown::thumbdown::thumbdown::thumbdown:
 

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I agree it cannot be removed based on the scenario you describe. You mentioned that the expanse of the 2x10 joists is 24'. Remember the tributary load on the microllam beam is 1/2 the total length of the joists it is carrying. That could be why your calculation shows the beam as overloaded. If the total length of the 2x10's it is 24', the beam is only carrying 12'. The other 12' is supported by whatever is carrying the other end of the 2x10 joists.

All that said, through bolting the microllam beams will do nothing to increase their strength. There' s a nailing pattern prescribed by the beams manufacturer that connects all 3 plys together. Adding more nails or bolts won't make it stronger. It may be more work but the correct thing to do is build a temporary wall under the 2x10 joists, cut them back away from the microllam and replace the beam with one that works. I just did this in my basement, took out a 16' triple 2x10 beam with a column in the middle and put is a 16' piece of steel with no column. Our local Microllam dealer has an engineer on staff so he sized the steel beam for me for a nominal fee since I bought all my other lumber there. Ask around at your local dealers.
 

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The post seems a bit odd to me. I find it hard to believe that a crew of carpenters took it upon themselves to select a microlam beam and install it without checking with a structural engineer at some point. Of course, I have seen some really weird framing down south during my hurricane damage inspection days, so I guess it is possible that a major structural elemented was selected, fabricated, and installed with no engineering involvement. Apparently it worked, the house is still there.

In the world I live in, a structural engineer would normally design the beam based on the loading and the geometry, then stamp the plans and thereby assume responsibility for the safety and adequacy of the beam. But perhaps there are parts of the country where you can just sort of wing it. Still, removing a column seems like a REALLY BAD PLAN, and as previously noted, bolting the beams together adds no additional bending strength,which is what you need.

Personally, I like the replacement steel beam idea.
 
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