[millerre]

We are renovating our kitchen. We are removing an 11 foot portion of a load bearing wall. we are thinking of using two 11 foot beams (2x10) and a 2 x 4 under them to support the portion we are taking out. The wall we want to remove supports a portion of the roof where a valley comes in as well. Is the beam made from two 2 x 10's and a 2 x 4 suffiecient. Or do we need to put a board vertically to support the beam in the middle of the room?

 

[Termite]

Not enough information. There is a lot that has to be taken into account in sizing a header of that length, specifically the imposed roof loads. My hunch is that 2x10's will be inadequate. Rafter span and roof dimensions have a lot to do with it. My suggestion would be to look away from 2x10 dimension lumber and give a harder look at LVL or PSL engineered lumber, which will span farther than dimension lumber. Visit a good lumberyard (not a home center, a lumberyard) in your area that sells engineered wood...Most of them have a designer with the capability and software to size the beam for you.

That being said, it is always best to hire a structural engineer when creating such large openings in bearing walls in a home. Interior and exterior bearing walls are often part of the structure's shear resistance, and creating large holes in shear walls is often problematic. An engineer can offer solid advice whereas the guy at the lumberyard can't. A permit is most certainly required by the residential code for this scope of work, and I'd be prepared for the inspector to request an engineer's written recommendations.

 

[Termite]

Another consideration is that you now have 11' of wall bearing on the floor below over its full 11', distributing the roof load evenly. The removal of the 11' and the addition of a header concentrates 11' worth of load into two points (the trimmer studs at each end of the header). Your home's structure's performance can be significantly altered by this change, and may be inadequate. Yes, even steel beams under bearing walls can be inadequate when things like this are modified.

 

[the carpenter]

11 feet is a pretty big opening for a load bearing wall. I would get a header sized for your area from local codes. even a 3 ply 2x10 may be too small. A manufactured beam may be the way to go (LVL). Around here, the local building supply store will get the beam sized from a truss factory (who has an official engineer) . Probably two plys of 11 7/8 LVL would be fine. Your described header doesn't sound beefy enough.

 

[ARI001]

KC has it dead on. There are way to many variables here to be considered for the proposed alteration. You need to consult with a structural engineer so that all issues relating to this job can be accounted for. The county will require this to be engineered due to the liability involved in this project. Also make sure you really research what you are doing if you intend to do the work yourself. This really is a project for a seasoned pro but if you are a highly skilled DIYer you can probably pull it off. What ever you do make sure you get permits.

 

[Scuba_Dave]

Yup, you can't guess on a beam size like this
I opened up a 13' wall between my kitchen & a new sunroom
I ended up with double 14" LVLs
I also had to install support in the basement along the rim joist to carry the load down to the foundation

You need to have the beam sized