How do you re-engineer trusses?

[1stwarrior95]

I like that idea Sureshot. I'm wondering now if it might be better to sheet it with plywood first and then do the horizontal 2x8's?

The way I see it, the section that was removed, (between J and H), doesn't really support the weight of the roof, but it does keep the weight from trying to "spread" the walls apart. (Kinda) For lack of better explanation... lol

 

[Justanoldguy]

Are you serious??
There is absolutely nothing to stop the roof coming down if the tie across is cut.
Yes the walls will spread, but at the same time the centre of the roof is sagging ready to drop.

 

[Sureshot]

May also sheet the adjacent rafters at B1 to tie the two adjacent ones to the cut one. Run a 2x flat from the top of the sill beside the cut truss at A to the adjacent truss at J as well to help contain any spread. Same on the other side. Could also run some 2x and span the adjacent rafters under the roof.
It is cut now so you might as well beef it up in a good way and see how it turns out.

 

[1stwarrior95]

Are you serious??
There is absolutely nothing to stop the roof coming down if the tie across is cut.
Yes the walls will spread, but at the same time the centre of the roof is sagging ready to drop.

Yes, I'm serious. And yes, you are correct. With the tie across cut the load will be transformed to a pushing effect that will spread the walls. If the walls could support that spreading force there would be no use for the tie across at all, but yes, I realize the walls aren't designed to support forces in that direction. (I know I'm not using the correct terminoligy here too).

But hopefully you get my meaning. Theoretically "If" the walls couldn't move outward the tie across would not be needed.
Each side of the roof is a seperate triangulated section. (points A,D,J, and C on the left side, G,D,H, and E on the right), or would be if the tie across were cut.

On the other side of the coin, I don't think any way of modifying the trusses to raise the center section, (like the OP and I would like to do), will be as strong as the original design. But I still think it can be done.