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edro 08-14-2011 09:36 PM

2 2x12" Header - Want to remove post
 
4 Attachment(s)
This entry way is between our dining room and kitchen.
The header is composed of 2 2x12" boards, 108" long.
The off center post is a 4x4" cherry post.

After tearing all of the drywall and plaster off, it looks like the header has most of it's compression on top of the post. As you can see, both sides of the header have cracks, telling me they are not under compression.
I don't think that it normal for headers that I have seen.

I want to remove the 4x4" post. If I do this, I think the cracks on both ends would tighten up as the weight atop the post would be transferred to the left and right ends of the header, where it is supposed to go.

Also, notice that there is drywall between the 4x4" post and the header (Also, the bottom of the column is on top of the linoleum flooring)... which tells me they added the 4x4" post later. The post is definitely under compression... as it is extremely rigid when I hit it with a hammer.

Any suggestions? Would you be worried about removing the 4x4" post?
Any way I can remove it "slowly" to see how the header reacts?

Thanks in advance!!!

Joe Carola 08-14-2011 09:44 PM

Quote:

Originally Posted by edro (Post 707438)
This entry way is between our dining room and kitchen.
The header is composed of 2 2x12" boards.
The off center post is a 4x4" cherry post.

After tearing all of the drywall and plaster off, it looks like the header has most of it's compression on top of the post. As you can see, both sides of the header have cracks, telling me they are not under compression.
I don't think that it normal for headers that I have seen.

I want to remove the 4x4" post. If I do this, I think the cracks on both ends would tighten up as the weight atop the post would be transferred to the left and right ends of the header, where it is supposed to go.

Also, notice that there is drywall between the 4x4" post and the header... which tells me they added the 4x4" post later. The post is definitely under compression... as it is extremely rigid when I hit it with a hammer.

Any suggestions? Would you be worried about removing the 4x4" post?
Any way I can remove it "slowly" to see how the header reacts?

Thanks in advance!!!

Just use common sense and ask yourself that it's there for a reason and who can possibly tell you on the internet that you can remove it. Do your homework and call a professional to come in and look at it for you. This is your house and safety I would assume must be an issue, right?

Aggie67 08-14-2011 10:37 PM

There are 5 or 6 things not to like in those photos. That has "I didn't check this out thoroughly before I installed it" written all over it. That actually looks like someone tried to open up the wall like you want to, then realized a goof and had problems, then went back to a center span post, and covered up the evidence. Classic. And that's probably the worst piece of lumber a person could select for a built up header (not to mention possible span issues). And not a whole of support on the right side, there. And I love how it's unbraced for its entire length. Crazy.

I also second Joe's suggestion. Get some help. Correctable, but you have an issue there.

I'd pay money to know where they landed the post on the floor. Is it on the subfloor, or finished floor? And is it at least lined up with a beam and column below?

TrapperL 08-15-2011 12:01 AM

To me, it looks like this was installed this way when the house was built,a large cased opening. There appears to be wiring run thru the corner of the beam in the 2 o'clock pic. It's possible that the beam did not hold correctly although it appears to be of the correct dimension for the span. The foundation may have moved and the previous owners decided to close it up- who knows. I would suggest if you want to remove the 4x4 to have an engineer take a look at it. He can advise you accordingly as to how to proceed. It also appears that there is a subfloor above it. The previous owners may have had a water bed up there or some other heavy object that caused it to sag and them to close this up.

edro 08-15-2011 07:16 AM

Quote:

Originally Posted by Aggie67 (Post 707494)
And I love how it's unbraced for its entire length.

I'd pay money to know where they landed the post on the floor. Is it on the subfloor, or finished floor? And is it at least lined up with a beam and column below?

What do you mean by it being unbraced the entire length?
Yes, from what I can tell, it is sitting on a structural member (8x8 oak beam), which has a column under it in the basement, down to the concrete floor.

Thanks!

Daniel Holzman 08-15-2011 08:31 AM

I will avoid discussing your interesting theories about mechanics of materials, specifically your conclusions about the cause of the cracking along roughly the center line of the beam, and your conclusions about compression in the beam.

I assume you are not pulling a permit for this work, and you don't sound like code issues are of much interest, so let's discuss this problem strictly from the point of view of how do you determine if it is safe to remove the cherry column. The answer is that it is safe to remove the column if the beam will adequately support the loads on it if the column is removed. You determine that the same way you design and construct any header, specifically:

1. You determine the loads on the header. This has not so far been discussed, it requires you to determine the tributary area to the beam, and multiply that area by the unit area load, which you normally get from code, but if you are not building to code then you get the factor by measurement, engineering judgement, or revealed truth from God.

2. Once you know the load, you determine the geometry of the beam, specifically including the clear span opening, and the connection details on the ends.

3. Then you determine the material properties of the beam. This can be difficult with an old beam, because it is not likely to be stamped with a rating, and you may not be able to determine the species, let alone the grade, of the lumber. But that is typically why you hire an engineer, they are supposed to know how to do these things.

4. Now you put it all together, and determine the allowable stress on the beam. If the maximum imposed stress exceeds the allowable stress, you cannot cut the post out. If the imposed stress is less than the allowable stress, then you can remove the post.

sixeightten 08-15-2011 08:44 AM

Based on what I can see, I would advise removal and installation of a new beam. What we can see is not very good, imagine what we can't see!

edro 08-15-2011 08:54 AM

Quote:

Originally Posted by Daniel Holzman (Post 707687)
I will avoid discussing your interesting theories about mechanics of materials, specifically your conclusions about the cause of the cracking along roughly the center line of the beam, and your conclusions about compression in the beam.

This house is over 100 years old with multiple renovations under its belt.
Obviously, nothing is to code and ever will be.

I posted pictures of the cracks hoping someone would give their advise on what causes those cracks. I gave my theory, but it sounds like you disagree.

Do you have any specific reason a header would crack down the center, on both ends, but not under the support column?

Also, I just noticed that the column is sitting on top of the linoleum floor... so it was definitely added much later than when the header was first installed.

Thank you again.

zircon 08-15-2011 09:33 AM

All of the above posts represent good sound advice from professionals. That being said, if it were my place I would be tempted,not saying I would do it, to peck away at the sheetrock at the top of the post. If the beam started to drop, I would stop and drive wedges in. If nothing happened I would remove more and if all the sheetrock was removed and the beam did not drop, I would consider removing the post. Not saying I would do it. Just thinking.

edro 08-15-2011 09:39 AM

Quote:

Originally Posted by zircon (Post 707708)
All of the above posts represent good sound advice from professionals. That being said, if it were my place I would be tempted,not saying I would do it, to peck away at the sheetrock at the top of the post. If the beam started to drop, I would stop and drive wedges in. If nothing happened I would remove more and if all the sheetrock was removed and the beam did not drop, I would consider removing the post. Not saying I would do it. Just thinking.

Great idea! The drywall is only 1/2" thick, so it would be a great place to test.

bob22 08-15-2011 10:53 AM

"All of the above posts represent good sound advice from professionals. That being said, if it were my place I would be tempted,not saying I would do it, to peck away at the sheetrock at the top of the post. If the beam started to drop, I would stop and drive wedges in. If nothing happened I would remove more and if all the sheetrock was removed and the beam did not drop, I would consider removing the post. Not saying I would do it. Just thinking."

You couldn't get me to experiment like that with your house much less mine. Daniel et al provided excellent advice as to what to do and that is get in an engineer; to do otherwise is mucho foolish IMO.

Ron6519 08-15-2011 11:01 AM

Quote:

Originally Posted by zircon (Post 707708)
All of the above posts represent good sound advice from professionals. That being said, if it were my place I would be tempted,not saying I would do it, to peck away at the sheetrock at the top of the post. If the beam started to drop, I would stop and drive wedges in. If nothing happened I would remove more and if all the sheetrock was removed and the beam did not drop, I would consider removing the post. Not saying I would do it. Just thinking.

You should be able to look at the sheetrock and see if it's been compressed from above.
From what I see:
The header is inadequate.
The supports under it are inadequate
-the right side only has 1 jack stud
-the left side 2, but separated
I would have installed 3 per side.
Assumptions:
The jack studs are not supported under the flooring, down to the main beam. This means that there is no solid blocking under the jack studs connecting the subfloor to the beam.
The remaining post in the middle(on a finished floor) is testiment of an inadequate structure that was put in to stop the header from dropping.
Removing it would be extremely bad judgement.
If you want the opening, get it spec'ed out by someone who knows what they're doing.

Daniel Holzman 08-15-2011 12:08 PM

To the question as to why the beam appears to have cracked along the neutral axis but not above the post.

Heavily loaded wooden beams generally crack horizontally along the wooden axis because horizontal shear is maximum along the neutral axis. Horizontal shear refers to the tendency of the top part of the beam (above the neutral axis, and in compression) to slide relative to the bottom part of the beam (below the neutral axis, and in tension). The horizontal sliding force creates the horizontal cracks which are commonly seen along the neutral axis of loaded wooden beam.

Horizontal shear is a maximum over supports, and is typically a minimum near the horizontal center of the beam (as viewed along the beam). Therefore, it is common to find horizontal cracking over supports, but often not in the middle third of a beam. However, there are other causes of horizontal cracking, including forces induces by moisture content changes, and forces due to point loads act very differently than distributed loads. The comment about the middle third of the beam having minimum shear applies to distributed loads, not point loads.

So let's get to the point. You are likely wondering why, if my theory is correct, there is minimal cracking over the cherry post. My answer is that most probably that post is holding a small load, hence is acting more like a decorative column, not a load bearing column. Hence the location above the cherry column is effectively the middle of the beam, where shear is minimum, hence no cracking.

Does that mean you should simply remove the column, declare victory and go home? ABSOLUTELY NOT. You need a complete analysis of the capacity of that header WITHOUT the column, as I described previously. And as other posters have noted, the supports on either end of that header do not meet code, or any version of standard framing practice.

So take my comments as an explanation for why there is apparently little cracking above that cherry column, BUT DON'T TOUCH THAT COLUMN UNTIL YOU DO THE ANALYSIS. And this analysis should be done by a professional, this is NOT a DIY, seat of the pants, I guess it will be OK type of thing, severe injury or death may result from removing that post if the header above is inadequately sized or improperly installed.

Jackofall1 08-15-2011 12:49 PM

Quote:

Originally Posted by edro (Post 707713)
Great idea! The drywall is only 1/2" thick, so it would be a great place to test.

That is a horrible idea, and something that shouldn't have been suggested!

Adding to Daniel explanation, removing the post may allow the beam to complete the horizontal shear that it so obviously wants to, this would lead to complete failure of the beam, possibly causing it to roll off the jack studs and effectively collapsing the structure.

Do some research, find the design code for what ever structure is above this do some realitively simple math and then go to the span tables for wood structures and then evaluate what you have and how to fix it properly.....or hire a professional for realitively little money in comparison to structural failure and have them evaluate and make proper recommendations.

As always Daniel the time you put into your explanations is admirable and so many times that I have seen unappreciated or seemingly discounted or misunderstood.

Mark

edro 08-15-2011 01:02 PM

I greatly appreciate the feedback and fully understand the lengthy reply.

I have looked up header recommended sizes and spans in the IBC. My span distance is 108".
Because this entry is into an added on kitchen, I went the safe route and used the "Roof, Ceiling & 2 Clear Span Floors" table for Exterior Bearing Walls.
It says the 2-2x12" header can support a 5'6" (66") span, but requires 3 jack studs on each side.
My installation obviously only has 1 jack stud on each side (2 on the left, but the inner one isn't even touching).

It looks like I need a better header solution.

Again thank you for your help. I will try to locate a residential structural engineer to evaluate my situation.

Edit: Updated with actual span length.


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