Question about rafters

[corner27]

I will start off by saying it's a question about my house, so I apoligize for that.
I just bought my first house, and I was up in the attic today. I was looking at the rafters, and they don't look like anything I have seen before. The bottom part of the attic is made up of "joists" that are split in the middle (assuming becuase they would have to be 30 ft boards otherwise) and laminated with plywood on the sides where it connects in the middle. The strange part is that these "joists" are not connected to the top part of the rafters. It looks like the top part are 16" oc, and the "joists" are 12" oc. Has anyone seen this before?
The main reason I was up there was beacuse I was trying to find out if any of the walls are supporting walls. Would the centre walls be supporting in this situation?

Sorry if this is confusing. I can go back up there and take pictures if it will make it easier to understand.

 

[KELLHAMMER]

It doesn't seem all that unusual. The horizontel joist is holding the walls together. Resisting the outward horizontel thrust created by the rafters. The two piece joist are tied or spliced together with the plywood plates essentially creating one continuous piece. The fact that the horizontel members are not connected to the rafters is not bad, but not great. It would be better if they were. My big question is there a wall located roughly at the center of the spliced horizontel joist at the floor below. The 12 inch spacing may have someto do with span of the horizontel members. Which I'm guessing are acting as a ceiling joist for the first floor. and the space above is just an attic.

 

[tdkkart]

In a conventional truss system the "joist" or lower stringer does virtually nothing except keep the walls from bowing outwards. The situation that you are seeing used to be very common.

 

[Motown 454]

My roof is like that it was stick built onsite, not trusses. Mine are short enough to not need plywood scabbing.

 

[corner27]

Yes there is a centre wall and I belive it is the supporting wall(red). In the basement, there is a beam made of 4 2x10's going right under the red wall with 3 pillers to hold it up. The green wall is the wall I want to remove. It has no wall under it in the basement, but has a 4x4 at each end in the basement. I assume this is becuase of the stairs being right beside it.

 

[Falcon67]

Yep, you'll not be moving that wall. Ours is similar, sorta. The joists are 2x4s that overlap in the center of the house and are just nailed. The overlaps all sit on a bearing wall. The underhouse beam is off to side about 4' for some reason, which is one reason the house got wonker-jawed over time. (built in 1926, moved in about 1950) It has several beams under there now.

You'll likely be OK to remove the green wall - unless you see something in the attic that would require that wall to carry the weight, it's most likely a partition wall.

 

[corner27]

The joists in the attic are I think 2x8, so they are pretty stong. What would be an indication in the attic that the wall is carrying the weight?