Latest Discussions : Roofing & Siding

mikeozo

07:04PM | 09/24/03
Member Since: 09/23/03
22 lifetime posts
I am in the process of constructing my 2 story house. The dimensions are 30x44. I am using 5/12 trusses with a 12" overhand on 16" centers and 5/8" Sheating.

We recently installed the trusses and began to install the 5/8" plywood. This is how we went about laying out. We first plumbed the gable truss and braced it in the center of the truss. We then layed out our 16" center marks from our gable end trusses to the rest of the trusses. When the trusses were in the correct spot, we installed a hurricane tie(the type that supports the truss on both sides of the truss). We then ran lateral braces across the peak and half way down the truss between the prak and the overhang. The trusses were now ready for sheating (or so we thought.)


We measured up 48" from our gable truss overhang. Then we stung a line across the entire 44' of the roof. When we began to lay the sheating on our control line, the plywood was running on an angle where the seam of the plywood lay on the truss. I could pull the truss out to make the plywood hit the truss in the center, but this seemed to bow the rest of truss.

This lead me to come to several conclusions... A- the building could be out of square, B- the wall with my beginning gable truss could be bowed in the center causing each truss after it to be bowed since they are braced to iton 16" centers. C-The hurricane ties are twisting the trusses or holding them from straightening out.

Now, We are fairly sure our building is square, or off very , very slightly. We were very careful to ensure this.

B- does not seem to be the problem because we released the braces from the gable to let free to move laterally. We then put the plywood back on the control line and it still is running off the line.

C- We noticed that some of the hurricane ties seemed to be holding the trusses out of plumb slightly on a few of the trusses. However, it doesnt seem to be a problem on the majority of the trusses.

We tried the plywood on several locations across the truss and the problem continued.

We have really been rackin our brains for the reason. I would love to have some fresh perspective and would greatly appreciate any help you can give. THANKS.

Piffin

03:11PM | 09/28/03
Member Since: 11/06/02
1278 lifetime posts
If the truss set is laid out the same on both walls, the walls are straight, and the braces for the trusses along the ridge follow the same layout as the walls, then the building is not square. Did you check the sqaure at the top plates? If the last time you checked was at bottom plates, there could easily be a wall or two slightly out of plumb enought o make this kind of difference.

rhagfo

08:20PM | 09/29/03
If the roof is a simple gable, then you could also check each side of the gable for square. Make sure the roof measures the same length at the ridge as it does at the top plate. diagonals should be equal.


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