I just posted this at the Architectural board but I thoght it could fall under this catagory to and I am real anxouse for a response. I will be working on this project in the AM. I hope posting on two forums is OK
I have just put up trusses that span 28 feet. There are gable trusses on each end and the rest are scissor trusses.
I used metal plates to tie in all four corners of the walls. Each of the scissor trusses are spaced 2 foot on center and are setting on a double 2x4 plates.
But, I set the gable truss on only a single plate so that it would be 1 1/2 inches lower allowing me to run my lookouts over the top with out having to notch them in. Codes say that you can have a single top plate as long as there is a 6x3 galvanized plate at the corner and each rafter or ceiling joist is within 1 inch from being centered over a stud. I am hoping the second part of the criteria is covered simply because the gable truss is supported continuously by the wall.
Now I feel sure that a single top plate can easily support the weight of the gable truss. Hopefully the inspector will also see it that way. However, after I put all the trusses up I realized that there will be a week point where the gable truss meets the wall because there will be no ceiling tying in at this point (scissor trusses/sloped ceiling). So there will be no lateral support at this point where the gable truss meets the top plate. So the extra 2x4 top plate would have been useful to add a little more rigidity.
Now I plan to put an interior wall somewhere close to the center of the 28 foot span and I plan to use a 4x6 extending all the way to the top course of the gable truss as the first stud (to give the wall lateral stability at this point). So then there will be only about 14 feet each side that will not have lateral support. I would like to run a 1/4 by 1 3/4 inch piece of angle iron down the single top plate bolting it to the top plate and to the side of the bottom course of the gable truss. I believe this will give me more lateral stability than a double top plate would have. So finally to my questions. Do I need to worry that the different contraction/expansion of metal verses wood will make combining the two a bad idea. Will the inspector think adding the angle iron was overkill and like it, or will he say what is this crap tear the roof off and start over again. Oh it is my house so the owner is not another consideration. I hope to deck the roof tomorrow so please respond quickly if you have any ideas. I guess I still could add the top plate right now but might not be able to real soon with out a great deal of difficulty.
Thank you very much for any help