Barn raising, sortof

[midlf]

Well I've been off TBN for a bit. Glad to see most of the familiar names are still here. Some time ago we were "acquired" by Chloe, a goffin's cockatoo. Long long story. Anyway she doesn't do well alone and we have limited caretakers sooooo we decided to get a motorhome so she can travel with us. (yeah, I know, we're nuts but what momma wants momma gets). So now we have this and I want to get it into our barn so I can work on this antique 12,000lb hot rod with plumbing. The picture of our "barn". The section to the right (east) is where we want the motor home to go into.

I'm posting a bunch of pictures and drawings to show the problem and to ask for ideas cause I sure need some help here.

 

[midlf]

This is the east end of the barn prior to our raising the door. It was a bit too low.

 

[midlf]

We raised the door header to allow the motorhome to get in. To get the door to work with the new opening we split the original door and had it go both ways. The header is now 124" high, plenty of room.

 

[midlf]

This is the existing roof framing. 30ft clear span. I would like to keep the span clear. Rafters are 2X8 and joists are 2X10. The joist is a collar tie that keeps the rafters from spreading the walls. I need to get additional clearance down the center 10 feet as noted on the drawing. This is the clearance I need for the GMC motorhome and for a two post car hoist. I need more than just the minimum clearance for the motorhome so I can jack it up and work on it indoors in the winter. The barn has heat.

 

[midlf]

This picture is the interior of the barn. The collar ties/joists shown are the problem. I want an additional 36" of clearance down the center 10 feet of the 30 foot span. I'd settle for 30". The height is to allow the motor home to be jacked up for work and for clearance for a two post car hoist. The joist is 111" above the floor. The motorhome is 114" over the storage pod, 111" over the front AC unit, 108" over the rear AC. The barn is 30ft clear span. The rafters are 2X8 and the collar tie/joist is a 30' 2X10.

 

[midlf]

Two more shots of the barn interior. Different angles to show the peak of the roof.

 

[midlf]

Here are two views of the collar ties/joists and rafters where they connect to the walls.

 

[midlf]

This is what the build office at the lumber yard proposed. I could live with the height at the center if it was most of the way across the center 10 feet of the garage. However it starts to get a bit low at the edges of the 10ft wide center area where I need increased clearance. This will be strong enough to bear the load but I'm looking for that little bit of increased clearance. Some extra effort at this time will save a lot of "rats" later.

 

[midlf]

This was one suggested truss configuration. It would give me the height but I don't think it will work. I doubt the 2X8 has enough strength at the connection between the two triangles. It might work with some extensive rework of the rafters with sistering, perhaps with some stiffeners. I know just enough to get myself in real trouble or to be very cautious. I'm going with the cautious as I don't want the barn to collapse.

 

[midlf]

This is another idea for a truss. Make the rafter strong as a truss and use double collar ties. This is shown as a single line drawing. Each line would be some type of 2X. Probably with plywood gusset plates glued and screwed at the joints.