Steel Beam versus Wood Header question

[s40er]

Looking for some advice on a header size requirement for a doorway I am installing in my basement.

Background: My house is a 1959 ranch with a basement and one floor with a crawl space attic. In 1983 an addtion was added to the house, adding a 12x18 dinning room off the back left hand side of the house and a 2 car garage with master bedroom suite above it attached to the left hand side of the house. Under this new 12x18 dinning room is a full foundation with access down from the garage.

The floor joist on the house side of the shared concrete wall are 2"x8" 16" OC and span 12' to the houses center support beam. On the new addition side the joist are doubled up 2"x8" 16" OC secured with metal joist hangers to a 2"x6" secured to the houses sill and spanning 12' to the outer foundation wall.

Question: I am in the process of cutting a 36" wide opening through the shared wall to connect the two basements.The cut through the concrete will span two joist from each side. The new roof on the addition is perpendicular to the roof of the origianl house and spans from the top of the garage over approx. 1/3 of the origianl roof.

Here is a rough sketch of a cross section slice of the house (viewed from the back of the house) showing where the new opening will be and the structure above it.

http://www.n-scaler.com/gallery/albums/userpics/10001/normal_cross_section.jpg

In consulting general handyman contractors that the roof on the addtion has made this a non bearing wall. The opening from the addtion in to the kitchen of the house is 62" wide and only has (2) 2x6's down each side for support.

Since head clearance in the basement is an issue I was looking into using a 4"x4" 14lb per foot steel I-Beam with (2) 2x12's glued & screwed together then concrete nailed to each side of the opening to support the I-Beam. The I-beam would be supporing two joist from either side and the span between the 2x12 supports would be 29"

Since everything I can find on the web in relation to header sizes and load limits talks about 2x6's on no bearing walls and 2x8 headers on bearing walls, I was wondering if any one could verify the 4"x 4" steel beam will do the trick.

Thanks in advance.

[mjpliv]

On the new addition side the joist are doubled up 2"x8" 16" OC secured with metal joist hangers to a 2"x6" secured to the houses sill and spanning 12' to the outer foundation wall.

Is this the area you want to put the door? If the "new" 2x6 ledger supporting the "new" joists is supported by the "old" 2x8 rim joist and is securely nailed (2 rows 6" oc) then the "new" floor loads will be supported over the opening. If you added hangers to the "old" floor joists over the opening then these loads would also be carried.

If I understand your question and the orientation of the joists at this location then this will eliminate the need for any header at all. My only concern would be a possible concentrated load from the jack studs for the doorway shown above. If possible, relocate the opening to be completely within that opening or completely outside of it. Are there any roof loads carried through this wall?

[s40er]

mjpliv,

Thanks for the reply. In the area of the new doorway, the origan 2x6 sill plate spans the opening. On one side of the opening, there are two standard 2x8 joist attached to this sill plate located over the new opening. On the other side of the opening a 2x8 is secured upright to (what was once the exterior). Two sets of doubled up 2x8 joist are attached by metal joist hangers over the opening area. There are no roof loads carried through this wall, but to be on the safe side, I am going to go with a header, better to over engineer than under :-)