I am in the process of evaluating a house for possible purchase. While
inspecting it I noticed that the roof was sagging. I crawled into the
attic and noticed that a main support timber had failed and someone
had attempted to brace it. You can see a photo here
http://s216.photobucket.com/albums/cc81/digital686/ This is not the
roof in question but ithe picture depects exactly what I found in the
attic. I plan on having a licensed roofing contractor evaluate the
roof. The house is circa 1955 and built on a slab. I do not see any
cracks in the stucco or drywall, just one small area that is sagging
on the roof above where this timber is. I was just wondering what
could cause this timber to fail?
Leaks are a good start, moisture from poor ventilation are good starts.
Poor construction and inadequate material can be factors. Be very careful
if you are buying this place. If the roof was left in poor repair, so were
other parts of the house. Be sure the price is right if you buy because you
may need major repairs.
The remedy is as important as the cause. Cause could be many things,
including insufficient rafter or bracing strength, or wood weakened by rot
or moisture. Roofers in my experience know little of substructure and rafter
sizing, bracing, and spacing. Also avoid "building inspectors" (no degree
For this issue, get a competent structural or civil engineer with full
knowledge of current codes for roof substructure building. They can tell you
why rafter bracing failed, how it failed, and whether a support structure
needs to be rebuild or redesigned. You'll find them in the yellow pages, and
can pay them per visit or per hour. Well worth it, if you are planning to
I don't know how representative the posted photo is of the roof in the
house that you are contemplating purchasing......
but from this photo the roof framing system looks to be missing some
Another guess here (& story from that guess) but I think you've got a
site built roof truss system.
Sometime in the past someone removed the struts that go from what you
are calling the "main member" down to rest of the house structure.
This allowed the "main member" to be over loaded & fail. After the
sag was noticed, someone tired to repair the situation.
Another guess here....I think the repair will be pretty easy, install
some temporary supports, true up the roof, sister the damaged memeber,
install properly placed struts, remove tmep supports.
BUT to be certain.......
I would suggest getting a "roof engineer" out to have a look, a few
$100's max & well worth it.
At least in my area there are civil / structural engineers who
specialize in roof assessment (necessary if going from wood to
tile). They have so much roof framing design / repair / retrofit
that they can usually tell by looking at it (no calcs) what you need
to fix it.
If my evaluation of the photo is correct your "main member" is
actually an intermediate member placed at ~ mid rafter span such that
small rafters (2x4's) could serve. It in turn needed braced with
struts every 4' or so to a bearing wall below.
I have a very similar roof framing system that I would love to remove
the struts to open up the attic space but they're need to support the
The hardest part will be getting a new lam beam up there to sister
next to or onto the bad one. You may need to make a hole in the gable
end wall then slide it all the way into the attic, unless you are
lucky enough to have a side vent or window to go through. In either
case go full length so the beam ends sit on wall tops under verticle
studs, and that your new beam is rated for the length/weight of the
Thanks to all who responded. I found the perfect solution to the
problem. I told the realtor I did not want the house. Two days later I
found the perfect house that all I have to do is move into it. I made
an offer on it last night.
Chuckle. Sometimes walking away is the best solution- we all only get so
many years of productive life, and just like you have to learn to choose
your battles, you also have to learn to choose your projects.
There are days I wish I had walked away from this place, and gone just
slightly further into debt to buy a place without a 'to do' list. No major
problems, and the basic structure is square and solid. But all the piddly
little stuff is turning out to be more of a time and money sucker than I
planned on, and I'm finding that even simple stuff takes WAY longer than it
did when I was a kid. The brain still has the knowledge, but after 20-some
years away from hammer-swinging, the <hands> seem to have trouble
With repairs and upgrades, I've already spent as much as I would have for a
fixed-up place or newer place, and could easily spend another 10-15k. But
then I would have more in the place than I could sell it for, what with the
recent market downturn.
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