Subject: Re: Use of Collar Ties in Light Frame Wood Construction
From: Steve Privett <eqretrodr(--nospam--at)earthlink.net>
Date: Tue, 05 Jun 2001 14:58:50 -0700
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.
* This email was sent to you via Structural Engineers
* Association of Southern California (SEAOSC) server. To
* subscribe (no fee) or UnSubscribe, please go to:
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
* send to the list is public domain and may be re-posted
* without your permission. Make sure you visit our web
* site at: http://www.seaint.org