I was up in the attic today, and noticed that I had a broken roof truss.
Not sure how long it's been that way. It didn't look too new.
Anyone ever dealt with this?
Rather then replacing it, I was just thinking about sistering in (or
sandwiching it ) another 2x4 with some screws and maybe some construction
This pic I found is a pretty good likeness of it.
Never dealt with it as a truss. I have encountered something close as a
If it were mine, I would sister on both sides the full length of the run and
call it done. I would use a lot of nails or screws and stagger them.
No - do NOT use lag bolts. Many screws in a roughly 2 or 3 inch grid
will hold more and weaken the structure less than larger lag screws. I
would definitely also glue the joint - good carpenter's glue would be
adequate, and urethane glue like Gorilla Glue Or Leapages PL Premium
would be excellent. drill the sister plates ovesize for one screw
every 2 feet or so to pull the repair together firmly then drive the
remaining screws. Properly screwsd together clamping would be totally
On Fri, 9 Apr 2010 19:19:25 -0400, "Steve McElrath"
I am still looking for the truss plan I got for my addition but as I
recall the engineered truss repair instructions for damaged trusses
said you sister the whole length of the member or a max of 8 feet and
use a shit load of nails/screws. The nailing schedule was on the plan.
Nail guns are the preferred method to avoid further damage. To that
end, big screws are better. Predrill the first few holes in one member
a bit bigger than the screw to get a tight fit before you run in the
rest of the screws.
The construction adhesive (assuming good quality) will do more for
strength than a whole bunch of screws or nails. In fact to do a
superior job, the sistered stud needs to be well clamped in place
before any fasteners are used. For fasteners some prefer ring shanked
nails or star head construction screws.
The problem with adhesives is getting the engineer who stamps the
repair plan to sign off on the longevity of the adhesive.
Make no mistake, a code compliant repair is an engineered solution.
Usually a good truss plan will have repair instructions included for
the various members so if it is damaged in transit, you are not
holding up the job waiting for engineering or a new truss.
Agree: For self home repair: To fix; if it is similar, say, to that
shown in picture I would sister both sides with longest length 2x4s
that will fit.
Glue both side to the broken one using screws to pull the whole thing
together. Don'think bolting through would be necessary! Maybe even a
temporary clamp or two for few days!
Be the strongest truss up there! Doesn't need to be thing of beauty,
although ponder on why it broke!.
We used lumber glue and then had to change something again; and
getting the new wood out tore the surface off the wood after a only a
couple of weeks setting up! No wonder some of it is called Gorilla or
Bulldog, or something glue! Great stuff.
On Sat, 10 Apr 2010 10:30:35 -0700 (PDT), terry
If there is no knot right there you have a valid question. If there is
a knot there the truss manufacturer has a serious quality control
Was there any evidence of a roof impact? Did something happen in the
What do the connecting plates look like? Any signs of a lateral
On Sat, 10 Apr 2010 14:42:10 -0400, firstname.lastname@example.org wrote:
I saw a house some years ago. The header beam across the garage double
door was poured concrete and after years it failed. About the center
it collapsed. You could see a "cup" in the roof. Didn't get to see the
attic, but the contractor was "thinking" there would be rafter damage.
Nothing hit the house, the beam just failed one day.
On Fri, 9 Apr 2010 19:19:25 -0400, "Steve McElrath"
Replace the whole 2X4. Easily done and the best way. I've sandwiched
some 2X10 floor joists and could never get them to last long. Ended up
knocking them out from center beam to sill and replaced them.
A few years ago I did a repair like this and contacted an engineer
buddy for advice. I placed strips of 1/2 plywood 8 ft long on either
side of the truss Plywood ran the length of the brace overlapping the
I'd use some method of pulling it together before sistering anything to
it. I'd probably get creative with some cable, eye hooks and a
turnbuckle to bring it together, then sister one side, screws and glue!
After a few days I'd remove the cable if in the way then sister the
other side. Yes more small screws instead of less large ones.
Lordy. It is a residential roof truss, not a damn bridge. Some 2x4s
across adjacent trusses, top and bottom, and some hammered-in stiff legs
between the 2x4s, and you can take all the load off the broken piece.
Same concept as making a temporary wall when you have to work on a
load-bearing partition. Either switch the broken board out and use new
nailers or gussets to tie it back in, or sister both sides.
I probably wouldn't even make it that complicated. Measure the same
piece on next truss over to get the length, cut the replacement, remove
broken piece, reinstall using some sort of lever or jack if needed to
get it back on the original mount points. I'd probably use a saber saw
and metal blade to cut away that part of nailer plates, and put it back
with oversize plywood gussets. A few dabs of construction adhesive to
position them, and then screw the hell out of them. I used to see
similar work done all the time down south, to repair where an HVAC guy
butchered trusses to install something.
Load like in a windstorm or after a foot of snow in winter, or after the
roofers dropped a whole skid of shingles right there. On a calm day,
that strut is mainly holding the ceiling up below it. Trusses are so the
rafters and ceiling joists can be real puny, and you can skip having a
ridge beam. And mainly because they go up faster than a stick-built
roof, and you don't need an expert there every day.
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