Roof Trusses - Nail To Interior Walls???

thom

I don't understand the clips. How do the clips hold the rock solid to the wall at the partition? I see a flange on the bottom of the clip, is there really a "C" channel that holds the rock in place?

Willie T

I have never tried this. But I imagine if you were to run a bead of adhesive on the top edge of the wall board before shoving it up against the lid, it would make a pretty good connection in and of itself. No clips, no blocks, no worries.

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"True eloquence consists in saying all that is necessary, and only that which is."
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Bill Everett - St. Petersburg, FL

Willie T

Here is what they look like.

Attached Images

 

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"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Bill Everett - St. Petersburg, FL

Framer53

Willie, I have read all the lit from the truss manufactorors. There is nothing in them about not nailing interior walls to them. In fact, they caution about nailing to low on the chord as to split it.

I have only seen the problem you are referencing once. It was covered up by the ceiling trim.

Please don't insinuate that we are wrong, according to local truss supliers we are not wrong.

I really believe that this problem is one that could be fixed without all the metal.

Willie T

I'm not insinuating anything at all about people. I'm flatly stating that this method should not be used. And I am giving thoroughly researched and documented reasons for my statement.

I, myself, used to do the very thing I now preach against.

When I began framing 45 years ago, we nailed the daylights out of the wall-to-truss connections. We thought we were being conscientious. We felt we were making the most secure attachment we could.

Well, we sure were. Too secure. The years have shown us that we made a serious misjudgement. After hundreds of call-backs, we began to catch on.

We learned a better way that gave the homeowner a better, more long lasting product.

Now, if you have come up with a better way to virtually eliminate that drywall intersection cracking, I know the entire industry would like to hear it.

__________________
"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Bill Everett - St. Petersburg, FL

Framer53

You missed the point I was making. You are preaching to someone that lives in a different climate than yours.

You are stateing that what we do is wrong. I am sorry to tell you you are wrong. Your statements may be applicable to Florida. I don't and have never framed their.

I do know that the local truss suppliers supply us with instruction sheets. There is nothing in them other than to nail to each wall securely.

Sorry, your blanket statements don't apply to us.

By the way, I am 55 years old. The last 15 years I was a foreman and responsible for the framing of in excess of 1000 homes and apartments. We don't have a problem that you are discussing except on very large trusses. Any in excess of 60'.

Willie T

Well, as long as you are happy. That's all that counts.

__________________
"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Bill Everett - St. Petersburg, FL

thom

Framer, truss uplift is a common problem. It is a function of truss length and temperature change. If the trusses are short, no problem. If temperatures are relatively constant, no problem.

The reality is, The webs shrink a little when they cool. That shrinking lifts the bottom chord, creating a crack in the sheetrock where the ceiling meets the wall. That crack is what this thread is all about.

The fact that you may never have a crack does not equal cracks don't happen. Nailing the bottom chord to the wall does not solve the problem, it does create other problems though. However, if you don't ever have a truss uplift issue, the whole thing is a non-issue to you.

Willie, thanks for the picture of the clip, now it makes sense. That does seem like a more cost effective solution.

Framer53

Thank you for your reply. Truss uplift is a problem with oversize trusses. It is not a problem on most houses. If it was I would have been responsible for an awful lot of work done wrong.

I think if you look back, I said that this does occur on large trusses. To imply this is a serious nationwide problem, is dead wrong.

JustaFramer

You ever heard of let-in bracing?


Last time I framed a house back in the day the use of Simpson L clips what was becoming common place. Don't remember the actual nomenclature for them but they allow for uplift. Also the use of sheetrock clips were used were the lid met the wall.

Willie T

I think it's great that NY doesn't have too many uplift problems. Wish we were as fortunate here. But for those in other states that may have experienced a bit more of it, here is a short, interesting article from BuildingScience.com that gives a little more insight as to why it occurs.



http://docs.google.com/viewer?a=v&q=...sCvDpgasDr8D0Q

__________________
"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Bill Everett - St. Petersburg, FL

MacRoadie

It's a function of how the truss is designed. There's a reason why they call them "two-point bearing" and "three-point bearing" trusses. If the truss is designed as a two-point bearing member, then you never nail at interior partition walls, you use the slotted clip because the truss is designed specifically NOT to attach to those interior walls, but is expected to move (otherwise they'd let you use an A35 or hurricane clip). Three-point bearing members get nailed only to the interior wall they are designed to bear on. As has been pointed out already, you add blocking to the top plate and nail/screw the edge of the ceiling rock to the blocking, starting to nail/screw to the bottom chord 7 to 12" out from the wall. The flexibility of that first 12" of sheetrock basically absorbs any movement between the truss chord and the wall top plate.

BillD

I first learned that nailing the trusses at interior partitions caused problems when I became a superintendent and had to take care of the 6 month and/or 1 year punchlists.

Bill

KentWhitten

We had one set of trusses that had 4" of deflection built into the design. They were 60' if I recall so obviously something to deal with.

I'm sure that it is still done around here, but not me. L-clips.

How many of you guys push that bottom chord to the top plate?

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kyle_dmr

I refuse to gun nail them to interior wall.
Will make the boys pull nails if they do it.
Hand nail ALL trusses to interior walls, leaving nail head up 1/8-1/4" to allow for movement. 1x4 bracing on 10' oc pretty much straight across the house. Doesnt matter if its nailed to walls or not.

On a good note, setting trusses tomorrow! I need to get a truss boom...

Chris@Sunrise

Trusses definatly move, alot even small runs of 24 ft will move substantially enought o crack mud. Most of the cracking isnt seen or the hangers over penetrated the fasteners witch allows the rock to flex. Not a proper install. To say this is irrelivant in some climates is dead wrong, everywhere was humidity and temperature change. If you think your area is exempt look at some commercial building prints. The building Im framing now has 1/2 gaps at ALL non bearing walls first floor to floor joist and second floor to trusses, all attachment is throught vtc clips and the first drywall screw is supposed to be 16" from the wall backing to joist or trusses. Ill post some pics of first floor framing tommorrow. Read your truss engineering again im sure it doesnt say nail to non bearing walls.

bimmerdream

So, it looks like there is a pattern here.
First step is the truss pack docs to be reviewed for nailing locations. If nothing there, then look at deflection in center of truss. If negligent, nail the sucker; if significant, L-clip the sucker. From everything I read so far, drywall corners tend to crack regardless how you nail the truss, thus the use of drywall clips is actually advisable, regardless of the the type and location of corners. So, from now on I think it should be better practice to avoid nailing / screwing drywall in corners and use clips to hold it all together... I can guarantee you that drywall guy does not care how trusses are attached to interior walls... So, it's just easier to require them to do what said above in all situations. How about this for a rule of thumb???
BTW, thank you for all your input.

Willie T

You might Google "GA 216-07" for a ton of interesting reading on preferred ways to install drywall.

__________________
"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Bill Everett - St. Petersburg, FL

MacRoadie

Except that in production framing, by the time the roof is loaded we're long gone. Before loading, you can't really see what the truss is going to do.

The best thing to do is read the plans/pack and if there is a lingering question, call the truss manufacturer.

KentWhitten

On a different note, this is really a fair amount of reading on trusses and proper installation methods. I couldn't find any reference to the bottom chord clips though.


Guide to Good Practice for Handling, Installing, Restraining & Bracing of Metal Plate Connected Wood Trusses.pdf

__________________
If you correct your mind, the rest of your life will fall into place ~Lao Tzu

Custom Cabinetry - Portland, Cape Elizabeth, Scarborough, Kennebunkport, Yarmouth, Falmouth, Cumberland, Ogunquit, Maine

Salmon Falls Cabinetry