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-   -   Replacing a load bearing wall (http://www.diychatroom.com/f19/replacing-load-bearing-wall-169782/)

mikem201 01-22-2013 12:08 AM

Replacing a load bearing wall
 
If I was to remove a load bearing wall I realize that a beam has to take its place. A beam consisting of 2 2x10's need to obviously be vertically supported. I have seen some people use a couple 2x4's on each side and create pocket for the beam to sit in but is that really sufficent? Wouldn't you need a column in the center of the beam? Also, do the supports need to extend all the way down to the foundation?

funfool 01-22-2013 01:15 AM

Yes and no.
How wide is the span, what is the weight above it?

carpdad 01-22-2013 08:07 AM

What you are proposing is called a header. A basic header of doubled 2x10 (or sometimes called 4x10, and usually has 1/2" plywood in between to make up for width of 2x4 plate), can only support one floor and an unused attic/roof, and it can't span more than 5-6 feet. It needs 2 jack studs (studs that go under the header) and one king stud on each side of the header. Jack studs support the header and king stud contains the header. 2x10 header with natural wood lumber can't do any more. Engineered wood header (usually called LVL) can do a little more.
Support for this load must be connected by building materials that are solid and can't be crushed (no soft shims like cedar and no wet wood that shrinks dry). People sometimes forget that there is a space in the joist bays and sometimes even between the wall and plates. The load must be connected down to the foundation with no interruption.
You see that I'm beginning to write a book. In your case, I would suggest a lot more research/self education and a help from a builder/architect/building inspector/engineer.

mikem201 01-22-2013 09:19 AM

so the 2x4 supports need to extend all the way down to the foundation, which in my case would be the basement? Now if the supports are already sitting on an exterior wall would they still need to extend all the way down since the exterior wall itself is sitting on the foundation.

jagans 01-22-2013 10:11 AM

No. If you are on the sole plate of the foundation, you already have full support. And how much load a double 2 x 10 can support is completely dependent upon the applied load. This type of header is used on openings bigger than 5 feet all the time. Consider a Bay Window. Your sole plate needs to extend under your supporting studs, so you aren't sitting on end grain.

mikem201 01-22-2013 10:13 AM

So anytime you add a beam the support must always extend to the foundation no matter what?

brockmiera 01-22-2013 10:39 AM

Actually what needs to happen is the vertical load needs to be transferred efficiently to the foundation. It is the easiest and most straightforward thinking to extend the support down to the foundation. In the even the vertical load from above cannot be transferred straight down another method must be used. In your case though you are already above the structural component of your concrete so the load can be applied perfectly vertical.

mikem201 01-22-2013 01:52 PM

Does there need to be a center support like a lally column? And if one of the supports is not on a foundation wall you would have to cut a hole in the floor and extend the 2x4's down to basement floor? Would you have to dig a footing for that? Would you use just a regular bottom plate on the 2x4 and anchor it to the concrete basement floor?

brockmiera 01-22-2013 02:23 PM

Those are a lot of what if's. If you can't post a drawing, sketch, picture, or something illustrating the situation at hand then the best thing to do is pay the money and have a residential structural engineer come out and take a look at it. He/She will be able to diagnose the issue and give you the proper solution.

mikem201 01-22-2013 02:28 PM

well what would you do? If its not sitting on a foundation wall your saying it needs to come all the way down to the basement, right? At that point what happens?

drtbk4ever 01-22-2013 02:37 PM

Center support will depend on the span and loads above it.

And if the vertical supports are not on a foundation wall, they shouldn't just sit on a basement floor. Typically a basement floor is only a few inches thick, which is not strong enough to support a vertical point load. You will need to open the concrete floor, dig a hole and poor a footer for the post.

Not sure if "footer" is the right term. Had a brain fart when I was typing this.

mikem201 01-22-2013 02:41 PM

and should i use the 2 2x4's as the post to be anchored in the footing since that is what was used for support in the first place?

drtbk4ever 01-22-2013 02:52 PM

I'd think for most small applications, 2 2X4's would be sufficient, but that is a guess. Ultimately, the size of the post required will be determined by the load.

That is why it was suggested to get a structural engineer to have a look and do the calculations for you.

brockmiera 01-22-2013 03:20 PM

There are a whole world of possibilities. You will need to have equal support all the way to a foundation. If you are saying that 2 2x4 jack studs will be enough to support your beam and the loads your beam is transferring then yes 2 2x4's will be able to take that load and transfer it to the lower lever. As was stated before, depending on the amount of load you are transferring to the slab, it may or may not require you to demo and place an additional footer support. size of footer and rebar requirements will also depend on the amount of load transferred.

brockmiera 01-22-2013 03:24 PM

Still we need more information to help you. You are opening up an exterior wall but you haven't told us where you are, what your live/dead/snow loads are. How far you are planning to span. Is this a ranch, two story, condo? If you truly want help then you should start opening up about what you are really trying to do.


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