# Removing posts in a basement.

• posted on February 20, 2011, 4:19 pm

The new span will be 23' uniformly loaded with joists 16\" on center. I would like to do a combination built up 2 x 10 wood beam or 9 1/2\" LVL with flitch plates to achieve a minimum of 1/360 of 23' stiffness. The dead load is 70 psf and the live load is 40 psf. How many plies of Dougles Fir/LVL and 1/4\" x 9 1/2\" steel plate would it take .
I have been told that a triple LVL will suffice, but I am a little leary about the 23\" span with the loads I have come up with. My math might be off a bit, but I come up with a wieght of 1760 plf. using a combined live and dead load of 110 psf. If so what would the deflection be using just LVL's?
I have yet to find a header span table that will tell me what the combination of flitch plates and any kind of wood are. Is there one available? Does anyone know a calculation I can use?
Thanks. Jon
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• posted on February 20, 2011, 9:51 pm
On Feb 20, 11:19 am, jon.moore1023_at_yahoo_dot snipped-for-privacy@foo.com (Jon Moore) wrote:

Beam height is obviously the major issue for you, and a 9.5" depth severely restricts your possible solutions. A couple questions. Your dead load seems exceedingly high, how did you come up with it? Is the existing beam a flush beam or do the joists sit on it? If it's the latter, you could bump up the depth of the beam considerably making it easier to comply with the apparent headroom restriction. It's a bit more work to cut back all of the joists, but it wouldn't take days.
I doubt it can be done with LVLs at that depth at a price point that would have it make sense. Steel would probably be cheaper. Call a local iron guy and get a rough ballpark for installing a 24' beam replacement. If it's a basement, they'll knock a hole in the wall/ foundation and slide it in.
R
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• posted on February 21, 2011, 12:45 pm
responding to http://www.homeownershub.com/construction/Removing-posts-in-a-basement-20521-.htm jon moore wrote:
RicodJour wrote:

The dead load is based on the wall above. The entire length of the beam is a bearing wall. 2x4 with 3/8\" drywall and 1/2\" plaster. 2x8 cieling joists with the same finish as the walls. 2x6 roof joists bearing every 6' from the ridge. The joists sit on top of the beam. The joist spaces above the beam are occupied with HVAC ducts, so using the space above isn't available. I agree LVL's alone at 9 1/2\" would not work. But with the addition of 2 to 3- 1/4\" x 9 1/2\" flitch plates sandwiched and bolted all togther with the LVL's I was thinking this would be enough. I just need to be sure. Do you have any information on the spans available for let's say 3- 9 1/2\" LVL's with 2- 1/4\" x 9 1/2\" flitch plates. One other question I have is how big would the footing need to be to take the added transfered load one one end. The other end would be in the existing beam pocket in the existing 8\" concrete foundation wall.
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• posted on February 22, 2011, 2:15 am
On Feb 21, 7:45 am, jon.moore1023_at_yahoo_dot snipped-for-privacy@foo.com (jon moore) wrote:

Back up there a minute. You are off base on a number of things. You have a beam that is taking first floor loads, attic loads (it doesn't matter if you don't think the space can be used or not, loads have to be attributed to it) and you have the roof loads. Snow, wind, seismic, and all the dead loads as well. And you also have the issue of bearing capacity, which would almost assuredly be exceeded if you went with a built-up wood beam.
My guess is that due to height restrictions and the overall cost of construction, you're probably going to need steel, and I'm not talking about some 1/4" flitches (3/8" or 1/2" plate is far more common). But if you want to see if wood will work, draw up some simple floor plans with dimensions, indicate joist directions and existing bearing walls, and take it to your local building supply. If they're in a good mood, and don't think you're in over your head, they might extend the courtesy given to contractors and forward it to their LVL supplier, and their in-house design will work up a solution. That's a lot of ifs, but it would be free.
The other choices are to hire an ironworker to engineer and install a beam, or hire an engineer or architect familiar with your local codes and conditions to design you a solution that fits your needs.
R
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• posted on February 22, 2011, 12:11 pm
responding to http://www.homeownershub.com/construction/Removing-posts-in-a-basement-20521-.htm jon moore wrote:
RicodJour wrote:

Ok. Thanks. I do have some friends in the engineering field. I will take your advice and use their expertise. I will let you know what transpires.
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• posted on February 22, 2011, 2:21 pm
I would think this is the best route. After all you are going to need engineering on your plan. john

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• posted on February 22, 2011, 5:35 pm
On Feb 20, 11:19 am, jon.moore1023_at_yahoo_dot snipped-for-privacy@foo.com (Jon Moore) wrote:
Hey Jon. This initial post of yours didn't go through that homeownersflub site - and I thank you for that, but your other two posts did. Why is that?
That hub site is an aggregator that has pissed off a lot of people for a number of reasons. Making money off of the free advice that people graciously provide on Usenet is a scummy thing to do. You will get flack for posting through there...just saying.
R