Here we step forward another several years to 1998. I had noticed that the roof
was beginning to sag considerably in the middle. In fact, it turned out to be
about six inches. This was also pushing the top of the front wall out about an
inch and a half or a little more. Investigation in the attic revealed the cause.
The roof was simply not adequately supported. There was nothing holding the walls
in except the collar ties and there was no ridge beam, just a 1 x 8. That, of
course, actually satisfies the building code but then proper collar ties and
adequate strongbacks are required to hold everything in place. Finally, the
purlin supports were at such a low angle as to give no support. The roof was
slowly falling down. Something had to be done and soon.
This photo shows the severe angle of the purlin supports The left side is over the living room where the insulation has been removed and the right is the front bedroom. Just above the purlin, you can see one of the 1x8 collar ties. I had already removed those over the living room to make room to work. I assume the builder placed them so low in an attempt to help keep the walls from spreading. It didn't work. The other photo is over the living room and shows the chain and come along system we first tried to raise the roof by pulling the walls in. That is the lone strongback and it was not attached to the roof or the walls at either end, just the ceiling joists. The ceiling joists run parallel to the ridge as the room is 16 feet wide in that direction by 30 feet long, from the front to the back of the roof, too long to span.
I had quotes from a couple of highly recommended contractors for the repairs. The roof is low pitch, allowing little room to work in the attic so it seemed that the best method was to remove the living room ceiling first. While it was out, I also wanted to have it raised as a pan ceiling to update the house a little. It turned out that the quotes were both $20,000 or more. I felt I could do it for much less so we elected to do the work ourselves.
The first step was to remove the ceiling and old insulation. There were only three
inches of it anyway as you can see in the photo above. We then built up a ridge beam
of doubled 2 x 12s with a 3/4 inch plywood spacer, glued and screwed together,
vertically supported at every point possible and tried to pull the walls back into
place with comealongs also shown above. Finding this inadequate, the final
resolution was a pair of hydraulic jacks under the beam. Once the ridge was straight,
the front wall moved right back where it was originally built. This did leave some
sag in the rafters though so we reinforced the purlins with 2 x 8s, also supported
at every point possible. This corrected all the structural problems. I finally
removed the no longer necessary remaining collar ties and added hurricane straps to
the rafters at the ridge as well as the walls.
These photos show the new ridge beam and the ceiling beam under it that will later support ceiling joists that run perpendicular to the ridge and tie to the rafters to hold triangulate the roof support and hold the walls in place. The stacks of 2x4s at either end of the ceiling beam rests on top of the living room walls and gives solid support to the beam. The 4x4 on to of it and the triangle braces support and stabilize the ridge beam. You can also see a collar tie in the background. At this point, the center part of the roof was back in position and straight.
All was not as well as could be though. Visual inspection from the street revealed
that the roof still had some sag over both the garage and bedroom ends, not nearly
as bad as the center was but still noticeable. We decided to apply the same fix to
the remainder of the roof.This photo shows the beam over the garage. This was a 20
foot span and I could only get 2x12s up to 16 feet. The answer was a staggered splice
with 4 feet added at one end of each board. Since the bedroom span is only 11 feet,
I thought one of the 2x12s in the beam could be reduced to a 2x6 as can be seen in
this photo. That was a minor mistake as it still allows a very small sag on that end.
Finally, this last photo shows an example of the replacement purlins. After the sag
was removed, there was still some sag in the rafters due to the inadequate support
of the original purlins. Since we would have to use them to actually lift the existing
roof, I decided to upgrade to doubled 2x8s instead of the usual 2x6. Also, I intended
to use the purlin at the rear to later support an add-on roof at the back.