Hello all,
This is my first post to this forum. I have a sagging floor in my kitchen and I thought it was just sagging floor joists (which are trusses, see “floor joist trusses 0001”). I did a cursory inspection and decided to “fix” the problem with 2×6 strongbacks (see FHB 166 p.104). However, on closer inspection, I found that one of the trusses had a cracked bottom chord (see “floor joist trusses 0010”) and it was sagging at almost 1 inch per foot! (see “floor joist trusses 0006) The gusset plates were even pulling from the top chord (see “floor joist trusses 0004). Then I noticed that the installer had butchered the joist right next to this one (see “floor joist trusses 0007).
So, to solve the problem, I was going to sister a 6 to 7 foot long 2×6 to the lower chord of each truss. The end of the 2×6 would rest on edge on the sill plate next to the truss and the bottom edge would follow the lower chord of the truss. I would jack up the truss and 2×6 from below until the truss was straight (no sag) and then nail through the 2×6 into the lower chord and any webbing members that I could. I would avoid nailing through the gusset plates.
What do you think? Am I missing anything? I know I’ll be slightly modifying the “truss-like” effect by nailing the webbing at locations along their length, but I think it will be structurally sound.
Thanks for your help,
Bob
Replies
Bob
It looks like someone re-engineered these trusses for you already.Picture 0007 looks like the end was cut off, or it was made out of a longer truss.I can't tell from the pictures how the other bearing points are, probably not pretty.
From your profile, you are an engineer. I wouldn't trust an engineer over the net to solve your problem, a local one is needed in this case.
When the engineer comes, have him look at the whole system. Don't wait to long.
Greg in cold Connecticut
just a thought, but why not jack the offending trusses up, and instead of sistering a 2x6, why not a couple of pieces of 1/2 or 3/4 ply wood, glued and screwed to the trusses...the full depth of the trusses? with that kind of access, that's what I would do...
Fengleman,
My thoughts exactly. Adding full-height plywood scabs to the side or sides of the truss assemblies should do wonders.
Screw and glue.
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As someone already pointed out, your trusses have been altered somewhere along the line. You icture titled "floor_joist_trusses_0007" shows one that's been cut off and not repaired AT ALL. Not a good thing.
The plate pulled out of one of those joints is also a problem. Again, it's likely damage from back when they were installed.
Judging from the looks of them, I'd guess the house is 8 to 10 years old? So contacting the truss manufacturer and/or the original builder isn't likely to do much.
Your proposed solution of nailing a 2X6 alongside them isn't going to do anything but waste time and get in the way of eventually fixing them correctly.
I'd suggest contacting a local truss manufacturer, and explaining the situation to them. They can likey refer you to an engineer who's familiar with trusses and truss repairs.
This isn't something you can get a solution for on the internet.
Boss Hog,
Thanks for the recommendation. I just emailed a local truss manufacturing company. They might actually be the company that supplied the trusses in the first place! I'll update the forum when I get a response.
Thanks to everyone for their time and help.
Bob
Bob,
Ive repaired these in the past and weve alvays used 1/2" or 3/4" osb.
Just like the other guy suggested, rip the osb or plywood to whatever the height of your floor truss is jack up the joist, glue it on the side and nail the sh*t out of it. Do this to both sides and stagger your joints.
Matt
Adding plywood isn't enough. You have to know WHERE to add the plywood, where to put the joints at, what thickness of plywood to use, and the nailing pattern. That all has to be figured out based on the forces in the members and what's damaged. Every repair is different.
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Boss is right, the only thing you can do with a 2x6 there is to whack the 'builder' over the head with it, then break all his fingers with it so he will never butcher another job this bad again.
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