Opinions on truss repair

[Brandon Whitmore]

Kurt originally posted

A lot of things done right would make houses damn near indestructible in high winds.

Simple things like gluing framing together instead of relying on (really crappy) nail connections. Glue joints, properly applied, are stronger than the wood pieces they connect.

We built an experimental house 30 years ago that only used PL200 construction adhesive, and only enough tiny nails to hold everything together until the glue set. When it came time to take it apart, we couldn't. Even the bulldozer ended up just pushing around the entire box.

I have a friend who had a large tree branch fall onto his roof, which cracked/ split one of his top chords of a truss. I let him know what he would technically have to do to have a repair designed, but........

I also told him I thought that gluing the top chord together just might be a really good repair. What do you all think?

[randynavarro]

I'd probably do the same verbally and off the record with almost anybody.

But, when it comes to putting it in writing with my name and reputation on the line. . . .

I go by the book on truss repairs. "Have an engineer design a proper repair, blah, blah, blah"

[Jim Katen]

Originally posted by Brandon Whitmore

I have a friend who had a large tree branch fall onto his roof, which cracked/ split one of his top chords of a truss. I let him know what he would technically have to do to have a repair designed, but........

I also told him I thought that gluing the top chord together just might be a really good repair. What do you all think?

I think that it would depend on how neatly the split occured. When a 2x4 top chord gets bashed, the wood is often damaged in ways other than the split. Fibers are crushed and the wood is deformed. A good glue joint depends on close contact between the two pieces being glued.

If it were my house, I'd cut away the damaged section, splice in a new piece and then run full-length, top-to-bottom scabs on either side of the chord -- from the peak to the top plate. I'd secure the scabs by first clamping them, and then driving 10d nails in every three inches.

- Jim Katen, Oregon

[kurt]

Sandwich it between 3/4 CDX strips. Use lots of construction adhesive. Nails are superfluous once the glue sets. Use screws to suck the sandwich down onto the wood to get a good glue joint.

It'll be stronger than the original member.

[jon_ran]

I had an engineer tell me that (for damaged webbing) sistering another board of the same size next to it and through bolting it would be an acceptable repair. Seems to me that it may work for the top chord too.

[Tom Raymond]

OK,

If the roof got wacked hard enough to break a chord, what else is broken? A damaged chord will distort the loads on the rest of the truss, and to some extent on the adjacent trusses. Also the force of the impact will be disapated through out the rest of the structure. I would look for;

Loose and/or damaged roof sheething on the entire roof.

Loose or damaged braces on the trusses.

Loose connections at the top plates, truss-plate and plate -stud.

Loose or damaged anchor bolts/sill plates.

Carefully check for racking, both the roof and the walls.

There was a similar incident a few years ago accross the street from my Inlaw's house. While it looked like a few sheets of plywood and some shingles would fix the mess, the AHJ said to tear it down to the foundation and start over, everything on the list above had occurred. It was a free standing garage so it wasn't too great a loss. The moral, I guess, is to not let the big broken "whatchamacallit" distract you from looking for the rest of the damage.

Tom

[Brandon Whitmore]

Thanks Tom,

buttttt this wasn't found during an inspection. I may have been up in the tree with a chainsaw and may have seen the entire thing go down [:-taped]. The guy who was supposed to be holding tension on the rope forgot (insert sound of beer can opening here) to hold onto the rope for the very last branch of the day.

The branch just barely swung into the roof and we did not think much of it until I went down to check the shingles for any scuffs. I found one scuffed shingle and then noticed it had hit right on the truss chord.

There is no damage to the plywood sheathing, and just a neat split in the top chord.

So, let's just say this was not discovered during the course of an inspection.

[Tom Raymond]

Sorry Brandon,

Didn't mean to coax an embarrassing confession out of you.[:-paperba

Just thought I'd share what I've seen happen when trees fall on buildings.

Tom