Roofing, Gutters and Waterproofing - Roof trusses

I am building a garage. The trusses are prebuilt and when it put them up i found that they were lined up near the walls 24 inch on center but 2 were warped near the center. I made sure that they were all plumb and level but the board didn't line up on the middle. Someone told me nail another board to the truss and nail the board down any way but i am not sure if this is right. Should i take the trusses back to the manufacturer or just add the board.every other board lined up o.k..

If by warped you mean they did not maintain the 24" on center spacing all the way across the garage over the length of the truss, that is quite normal. There are metal braces (or you can use wood) for top and bottom cords that should be installed as the trusses go up to maintain spacing and alignment. Also, because of the 24" spacing and the up and down variability of the trusses it is often best to install strapping 16" oc to attach your sheetrock. Being a garage, that may not be necessary, but it illustrates that trusses are never perfect.

When you get up top to apply the roof sheathing, that is where you will appreciate a well aligned set of trusses. But make sure you pull everything into alignment as the sheathing goes up so the last ones fit as well as the first.

enjoy
Bud