Dry Wall Backers – what really works?
Drywallers –
What method of running backers really works? What method causes crack?
For years we have nailed 2x4s to the tops of various walls for backers. It seems to be a common technique. Hey, we even installed the gable backer on the deck which left a nice 1.5″ pocket for the gable truss to land in and something to nail it off to.
Now the boss wants us to hang the gable end wall backer from the bottom chords of the trusses, so it floats with the trusses. More work, more time. The rest are floated between truss chords.
Worse, he want the 2x4s supporting the gable backer to be nailed to three chords, so we can’t use the stuff we cut for the truss installation cat walks. Seriously, it only has to support 24″ of drywall. Three trusses? Not a balconey.
As for cracking, the drywall on the walls isn’t going to move. The lid will move down regardless of method.
What method is Best Practices from your point of view?
The ToolBear
“Never met a man who couldn’t teach me something.” Anon.
Replies
I don`t work with trusses, but thought you deserved a bump.
J. D. Reynolds
Home Improvements
I can't answer your question, but out of curiosity, would you tell the boss he's wrong?
I told him that I did not grasp the reasoning behind this procedure.The ToolBear
"Never met a man who couldn't teach me something." Anon.
I did a thread on truss uplift a long time ago. It's still here, but needs updated:
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=24607.1
All the links in that thread are dead. So I attached the WTCA document on truss uplift to this post. It has some decent pics which explain potential problems pretty well.
Unfortunately, the document has been set up so you can't print it. (They want you to buy them) But any truss manufacturer probably hands these out and will be glad to give you a copy.
I don't completely understand your descriptions of how your boss wants you to run your backers. But it sounds wrong from what I could tell.
BossHog -
Tnx for the data. Send same to boss.
What kind of angles are they using on the bearing wall in the .pdf? Truss clips? Have not seen that one. We clip all the interior walls and there are hurricane clips on the exterior.The ToolBear
"Never met a man who couldn't teach me something." Anon.
I haven't met a drywaller yet who cares. All they care about is that they have some kind of backer. The link you got below is good, the best you can do is to not screw the lid 16" from the walls and let it float at the corner joint. I've never heard of truss uplift affecting any exterior wall, gable or otherwise. If cracking is a problem at the exterior walls it is prpbably due to shrinkage and/or settling.
It is just common sense that a gable truss' don't lift. They are constructed differently (usually) and have no W braces, and the drywall doesn't even attach to them! It attaches to the backer on top of the wall.
Woodroe
Toolbear, your saying some things that I'm not quite sure what you mean.
We've always attached the backer on the gable end and flew them up.(of course we also sheath the entire gable and put the overhangs on too). We don't do this to prevent uplift issues though because there isn't any uplift on gable end trusses.
blue
Let's say downlift instead. I can see where uplift implies the roof coming off.
The trusses will move down when the roof is loaded and normally our backers are on the exterior and interior walls, not hung from the bottom of the truss chords.
The DWers won't be in until after the roof has been loaded, so it should be down.
If there is movement, I don't see how hanging the backer will prevent it. The DW on the wall will not move, regardless of where the lid backer is hung. Or does this work?
Staying 10" out for the first screws is something we do.The ToolBear
"Never met a man who couldn't teach me something." Anon.
"If there is movement, I don't see how hanging the backer will prevent it."
Floating the corners doesn't PREVENT movement - It just conceals it.
"What kind of angles are they using on the bearing wall in the .pdf? Truss clips?"
The pics show drywall clips. But backer boards work fine also. And there are companies that make special stuff for this situation.
There are two kinds of people who never amount to much: those who cannot do what they are told, and those who can do nothing else.