OK so I decided I will first install the new beam under the truss heels, go back 5' or so and put another one under the next panel point, then back another distance to another panel point. So a total of 3 sets of double 2X10s.
First, I cut down some sheetrock on the two walls that are about 9.5' apart where the new beams will span. Solid poured concrete wall the entire wall top to bottom, sweet. I attached the 2X10 on there like an ledger board, using 1/4" Tapcon screws. Yes, I know Tapcons are not going to cut it for shear loads, so I will put in some 1/2" lags later. But in any case, this board will not be carrying the bulk of the load. The reason I put up the boards across the wall, is to provide an anchor point for the joist hangers for the three sets of beams.
The other side is part solid concrete up top, concrete blocks below, and a section of it is 2X4 wood studded wall. I attached like the other side the 2X10 across the top, using Tapcons on the solid concrete, and headerLok screws to the wood studs and top plate.
So now I have this temp wall across the space, and the two walls have the "ledger boards" in place.
I then raised the double 2X8 beam up against the old jacked up joist hangers. The beam has a real tight fit between the two sets of 2X10 ledger boards. Then I used a set of Simpson Strongtie double shear hangers HGUS28-2 under the 2X8s. I attached the hangers to the beam, not the header.
I then installed a 2X4 under the header all the way to the slab (had to cut away tiles to allow the lumber to sit on the concrete slab).
Then I put a 4X4 post under the double 2X10 header on each side of the wall.
So this is what I have now.
The beam under the original joist hangers supporting the truss heels. You can still see the temp wall to the right that is now a tad loose. I haven't removed that yet. It's there for insurance LOL.
The two 4X4 post with a 2X4 behind it, so it's like a 4X6 post sitting on the concrete slab.
Top of the post where the double 2X8 sits. The 2X10 header in this case is not really taking the load. On top of the post is the double shear hanger with the double 2X8.
Note that nothing has been permanently fastened yet.
I have not nailed in the joist hanger to the header, or to the beam. I have not tied the trusses to the beam with any straps, I have not attached the 4X4 posts to the walls. Everything is now just "sitting" there from the weight.
I now have a few questions.
(1) The Simpson Strong Tie instructions said to use 1.5" 10D nails to attach the hanger to the header. OK the 1.5" nails work because the 2X10 header is 1.5" thick. Behind that is solid concrete. But there are 2 sets of diagonal holes I am supposed to pound in to attach the beam to the header lumber. What size nails should I use? Surely longer than 1.5" since the skewed holes are 1" back from the header and driven in at an angle?
(2) It also said to use 1.5" nails to attach the hanger to the joist. In my case it is a double 2X so I have 3" of width. Should I drive in nails LONGER than 1.5"?
(3) The HGUS28-2 is specifically designed for using a set of two 2X8s. Yet when I wrapped it around the 2Xs, there is a gap of about 3/16" on the side. Why is that? Any idea? Isn't it supposed to be a snug fit? Am I supposed to shim that gap? Or put a piece of 3/16" thick filler between the two 2X8s? If you look at the pics below you can see the gap I am referring to.
Once I have this all sorted out and permanently tied in, I will move back 5' to the next panel point and put up another double 2X, then a third set. This is why I put a longer header across the wall on both sides.