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Re: Use of Collar Ties in Light Frame Wood Construction

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Dennis,

Were the original ceiling joists actually tied to the rafters and did they maybe only connect every 2 or 3, as would happen with dissimilar spacing? Is the roofing something other than composite and the weight maybe too high for the "conventional" 3 16d? If the original connection was inadequate even for unanticipated loads such as an "engine hoist" and the ridge has deflected a couple of inches, are the walls still plumb enough to be acceptable. I think UCBC or Abatement of Dangerous Buildings translates to 1/3 the width or about 1.167" for the typ 2x4 wall.

I've had a similar situation where the roofing had been replaced with a heavier material, the ridge sagged, also slitting the ridge board, and the center of the perimeter walls were out of plumb by over 2 inches. The remedy I went with was to jack the ridge back up, replumb the walls and install additional ceiling joists that were actually designed to carry more than the traditional 10psf live load. As the load to the roof had been increased, I double checked the rafters and found they too were over stressed by more than 50% so opted add "web" members to the "truss". The heel connection, (rafter to cj) did require more than the traditional 3 nails and I was concerned about getting adequate edge distances for bolts in the tight space above the wall, (we left the roof sheathing in place) I went with a plywood gusset plate.

HTH

Steve Privett


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