Expert: Bruce E. Johnson - 9/24/2010

Question
QUESTION: Hello,

I have a two story house with a basement.   It's of the beam and column design, where the basement has a main beam (3 - 2x10's) running across the entire width (16-18') of the house.  The beam is supported by two lally columns (3 1/2" 16 gauge) which are concrete filled. equally spaced in the middle of this span.
On the 1st floor resides the kitchen and dining room at one end of the floor, and the living room at the other end.  On the 2nd floor, resides a large bedroom/bathroom/closet.

My question is the following:

- Currently the kitchen is in one corner enclosed by two walls (one load bearing and the other not).  The load bearing wall runs directly above the beam in the basement, and takes up roughly half the width of the house.
The dining room is directly adjacent to the kitchen. I want to bring down these two walls and make the kitchen and dining room as one.  In the new renovation an island will create separation between both areas.

The load bearing wall I mentioned above, is load bearing because it partially supports the floor joists that make up the 2nd floor.  The load bearing wall shares the support of the floor joists for the 2nd floor along with a secondary beam that sits on top of it at one end, and then goes all the way to the other end of the remaining span, terminating on an outside exterior wall into a support "pocket".  In other words the "support" for the 2nd floor is made up of equal parts load bearing wall and beam.  The beam here is also (3 - 2x10's), and measures roughly 9 feet in length.

I want to know how feasible is it to replace the load bearing wall with a similiar sized beam that's currently there.  The two beams would meet roughly in the middle of the floor span and be gussetted together.  Then I would put a steel fixed column (11 gauge, 3 1/2 diameter, which roughly supports 6 ton) directly underneath this union.  The post would be directly sitting on top of one of the concrete filled posts that is in the basement.  What concerns should I have with this solution?   Do the loads seem correct?  Do I have to fill the new steel column with concrete even though load rating is satisfactory?

The steel column I have in mind would be something like this (the 8ft one):

http://www.tigerbrandjackpost.com/fixed.htm

Thanks,
Amado Gonzalez
Northern New Jersey

ANSWER:  Hi Amado, it sounds like you are on the right track.  I like the idea of stacking the load bearing, i.e. the two columns are in line, one above the other.  I don't know how big the footing is under the concrete filled column in the basement though.  By concentrating the load on this column you are adding to the load of the footing under the slab.  For calculations sake: say the pad under your slab is 2'x2' or 4 square feet and the concrete is 2500 psi and the ground is capable of supporting 2500 psf then this column is sitting on a footing that is theoretically capable of supporting 10,000 pounds. A larger pad would obviously be capable of supporting more weight.  Since half of the new beam was previously supported by this foundation pad and some of the wall weight (the wall you want to tear out) then you should be fine.  I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com

---------- FOLLOW-UP ----------

QUESTION: Thank you Bruce for your quick response to my initial question....The footing question is something I didn't think about and I will have to investigate that.   What do you think about the fixed column posts that I am thinking of using?   They come empty (no concrete filling), but seem to have adequate load rating.  Would you have a recommendation on other vendors that may sell similiar fixed posts.  Do I still have to fill the fixed steel column post with concrete in my situation?  I'm thinking that the reason why the columns in the basement are concrete filled is because of the gauge of the steel used on the post (16 gauge).  Possibly too thin.

Thanks again,
Amado Gonzalez
Northern New Jersey

Answer
Hi again Armado, sorry I forgot to address that part of your question. I have used many columns without concrete filling.  Oftentimes the filling of the column with concrete is more of a fire rating issue and is at the discretion of the engineer.  I don't see where you need it in your case.  The column you refer to doesn't specify that it needs to be filled so I say, don't fill it.  It's possible that the engineer of record that designed the structure of your house wanted the column in the basement filled for some specific reason, maybe to tie it into the foundation, or keep water from getting into it or as I said earlier for fire protection..Since the column in the basement is holding up the two upper floors as opposed to the column on the first floor only supporting half the weight I don't see an issue here if you don't fill it.   I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com