basement support posts

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  #1  
Old 01-01-13, 07:57 AM
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basement support posts

I am looking to purchase a log home with a full unfinished basement. Walls are block and the main beam is 4 2x10s with four support poles. The poles are set in concrete at bottom and bolted to beam at top. The problem is the main level floors(hardwood) are slightly raised (hump) parallel with the beam. The basement poles are not adjustable. I am thinking of getting 2 adjustable poles and place one on each side of a post and jack up temporarily and remove a small amount of the beam where the pole is bolted. then lower back down and remove temps and go to next. Is this a bad idea or is there another solution. I have looked for an adjustable top I could cut each beam and replace top with an adjustable one but I cannot find such a fixture. Any Ideas?
 
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Old 01-01-13, 09:04 AM
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Your plan could be ok but we're not there to see it. Best bet is to have a structural engineer come out and give his/her blessing.
 
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Old 01-01-13, 09:07 AM
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No expert...and I doubt it would really matter if you are talking 1/4" or so...but I wouldn't notch the wood beam.

Better to cut the top of the supports, reattach the top, and add metal plates as needed to get to the correct height.

Yes, it would be more involved and expensive...but it's the right way to do it.
 
  #4  
Old 01-01-13, 11:32 AM
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basement support posts

I think it would only be a 1/4" to take out. I have a friend that is a structural engineer. I think I will give him a call.
 
  #5  
Old 01-01-13, 05:28 PM
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Someone needs to determine what is causing the beam to raise up with respect to the exterior wall supports. It could be sill plates rotting and compressing on the exterior walls as well, such that the floor joists have dropped down. You need to stop the process, or risk having to do corrections again in a few years. There's always the possibility that it just might have been built that way.
 
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Old 01-01-13, 05:45 PM
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Are the 2x10's SPF framing lumber or are they engineered LVLs? I've heard of LVL's staying the same size while the framing lumber shrinks slightly, leaving a "hump".

Deflection in the floor joists on each side could also make it seem like a "hump" in the middle. Are the floor joists also 2x10s? How far do they span? Are they sitting in hangers on each side of the 4x 2x10 beam? And is there cross bracing or bridging between them at any point?
 
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Old 01-01-13, 09:15 PM
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I had this problem in a former house.
Pulled up the carpet floor, and found a 3/4-1" high hump running the whole length of the house.
Apparently over 45 years, the joists on either side of the supports sagged, leaving the center line higher.

My solution was a creative adjustment of the flooring above involving a whole lot of sanding...
 
  #8  
Old 01-04-13, 02:15 PM
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All lumber is SPF and all solid including sill plates. I feel it was constructed this way with non adjustable posts set in concrete, The block wall could have settled a small amount. I won' get posession for 6 more weeks but I will keep looking for a solution. This is a log home so logs 8" X12" are lots heavier than stick built.
 
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Old 01-04-13, 07:07 PM
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Wait a minute!!! We're dancing the to the wrong song. Logs are super heavy and can cause foundations to sink slightly. In fact they will shrink themselves causing havoc with windows and doors as well as partition walls in the house if proper precautions aren't met. I'll have to side with the others that the exterior foundations have sunk slightly leaving you with a bulge.
 
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Old 01-04-13, 07:45 PM
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Wow, that would suck. If that;s the case, what's to say that it's done settling? Or that it was built with the proper footing in the first place?

I would think that if you provided some temporary supports that were the correct height, it would be a piece of cake for a welder to cut the columns and then reweld them one at a time at the proper height. Of course, this would probably void any rating that the post formerly carried.

Unless I'm mistaken, adjustable steel columns do not meet code anywhere in the USA as permanent supports.

Using temporary supports, moving the column away, and mortising the bottom of the beam sounds like a workable plan in my book. Notching the beam does affect the beam a little but as long as the notch is pretty shallow I don't think it would be an issue, since it would be at the bearing point, not in the middle 1/3 of a beam span.
 
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Old 01-04-13, 10:06 PM
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Sorry, Sleeper, but notching any continuous member at its support points is never a good idea. Mainly because the maximum (negative) bending moment typically occurs at those locations, and is normally larger than mid-span positive bending moments. Notching the bottom moves the neutral axis upwards, increasing the unit stresses where strength is needed the most. Not a problem if the member is over-designed to begin with, but can be if actual loading is close to (or exceeds) maximum design values.

Fall-down-go-boom is never good, even in a log home. I lived in one in Colorado for 6 years, and have to say the thing was really stout. Never any creaks or groans, even with 50 mph winds and very heavy (8.5' measured at one point, the last year we were there) snow loads.
 
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Old 01-05-13, 04:56 AM
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My log home called for 24" wide footings with 12" block, so I would question what the OP has for support and go from there. I would take a combination of suggestions, and either pour new footings adjacent to the existing posts, temporarily support the structure with adjustable sizable posts, get it all right, then build block piers on the old footings if they are large enough, removing the adjustable posts.
 
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Old 01-05-13, 05:46 AM
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Bridgeman, I agree that notches should be avoided, for the reasons you mentioned. However they are allowed by code, and the op is talking about 1/4". This seems well within reason.



R502.8.1 Sawn lumber. Notches in solid lumber joists, rafters and beams shall not exceed one-sixth of the depth of the member, shall not be longer than one-third of the depth of the member and shall not be located in the middle one-third of the span. Notches at the ends of the member shall not exceed one-fourth the depth of the member.

IBC 2308.8.2 Framing details. Notches in the top or bottom of joists shall not exceed one-sixth the depth and shall not be located in the middle third of the span.
 
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Old 01-05-13, 06:09 AM
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Something that just occurred to me as another option that we haven't discussed, is that it's possible that the existing columns are adjustable, but the adjustable part may be buried at the bottom by the concrete pad.

Do your columns sound hollow, or have they been slugged with concrete?
 
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Old 01-05-13, 07:03 AM
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I did check doors and windows and they operate fine and were built properly to allow for setttling of logs. I think the problem could be corrected as someone else said by cutting posts take out 1/2" and reweld and shim with steel shims to a level floor. not disturbing integrity of beams.
 
  #16  
Old 01-05-13, 10:33 AM
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Sleeper:

Not wishing to beat a dying horse here (regarding beam notching), but a few thoughts come to mind. First of all, notching any beam at its support points as you suggested just doesn't make sense, as the supports first have to be removed to enable notching to be performed. Why not modify the supports while you have them in your hands, instead of chopping into a perfectly good beam? Secondly, just because something is or isn't allowed by Code doesn't necessarily mean such is based on sound engineering practices. Don't most builders include longitudinal reinforcing steel in residential concrete foundation footings, even though unreinforced footings have been allowed by the IRC (except in seismic zones) for a long time? The Internachi sketch you referenced does not specifically address notches right at the points of support of continuous members, only near the ends and mid-span of what are presumably simple spans. And no consideration is given to the inevitable stress-risers and tendency to crack along the grain at the sharp, re-entrant corners of the notches, caused by notch-induced tension forces perpendicular to grain stresses.

It sounds like the OP is on the right track with his plan of attack.
 
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Old 01-05-13, 10:36 AM
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That was me...better to modify the supports than to modify the beams. It's what I would do, even though it's a PITA and will take more time and money most likely.
 
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Old 01-05-13, 12:01 PM
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A notch at a column is no longer a midspan notch. A notch between columns would be considered a midspan notch. It's probably a moot point anyway since I noticed his first post mentioned the base of the columns are set in concrete. I doubt you could move them to the side to make the notch in the first place!

That point is what got me to thinking that if the columns are set in concrete, they might be adjustable, setting on a footing and that breaking out the concrete floor around the column base might open up the possibilty of readjusting the column, if the cement could be knocked off of the iron so as to make the adjustment. Then the floor could be repaired.

But cutting the column and rewelding it would likely be easier that that. I just worry that someone reading this will jump all over the fact that a welded post may not maintain the same inspected load rating as the original. But I would think that if the post was shortened at the top, directly under the beam saddle, that it wouldn't be like you were adding a 2nd welded joint.

I like Vic's idea of cutting the column short enough that some steel plates could be used in the saddle as shims, which leaves the possibility of taking those shims out in the future if needed.
 
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Old 01-05-13, 02:23 PM
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Despite your attempts to muddy the waters ("notching near ends vs. mid-span"?), you might like to know that a welded splice utilizing E70 electrodes and full-penetration welds will be considerably stronger than the original steel columns. Not including amateur work, of course.

I should know, having spent a few thousand hours as an AWS-CWI, performing weld tests and structural steel inspections in fabrication shops over the years.
 

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Old 01-05-13, 03:35 PM
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I'll have to jump in and comment, sorry. A notch over a support is still supported if the support is the same dimensions or larger than the notched member. A notch midspan is not supported and compromises the wood. We are talking wood.
 
  #21  
Old 01-05-13, 04:18 PM
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WOW never expected all this input. I have to say I have learned some things. I am also a Home Inspector and I know the basement blocks are 12" not sure what footing but it was built by a reputable log home company in 1994. Still in perfect condition except for this one Item . Thanks for all the input and I will get my friend Leon Morris the structural engineer to buy off on what I decide to do. Thanks for all the input. Great forum
 
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Old 01-05-13, 04:30 PM
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Let us know what he suggests as a viable remedy so we can release the pool money on the bets Just kidding.
 
  #23  
Old 01-06-13, 12:29 PM
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Let me ask what seems like a crazy question, for the sake of discussion.
If we are talking a fraction of an inch... then... why does it really matter?

I'm a big fan of doing things the right way, but I'm curious as to what is really being harmed by just leaving it. I'd think that for such a small difference the effort involved in just working around it above (e.g. maybe need creative solutions for flooring changes? what else?) might be less than the can of worms that could be opened by trying to mess with it.
As mentioned - the settling may not be done yet. Are you going to just suffer the same problem again in 10 years anyway?
 
  #24  
Old 01-06-13, 02:15 PM
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I am already 74 hoping for another 10 tho.LOL
 
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