benick wrote:
(snip)
Here is a Bing search with many links for you to look over about
strapping a ceiling...Pay CLOSE attention to the one about Truss
movement and learn how to do it right...
http://www.bing.com/search?q=strappi...st=1&FORM=PERE
OK, I'll look...
1. An East Coast jack-of-all-trades thinks strapping is a good idea. No
surprise there, but no compelling rationale either.
2. TOH video. Remodel. They're hanging over an existing strapped and
lathed ceiling. They made some structural changes, so need to add a bit
of strapping to maintain the existing plane of the ceiling before
hanging. Also note they use 5/8 firecode, not 1/2".
3. DIY site.
"the ceiling should be strapped to ease installation."
"Installation is about 5x more difficult! Without strapping"
Not a good reason, unless you find hanging difficult without it.
"Unlike wall installations where the studs never move."
Wall studs never move? He must not ever operate
doors or windows. Nor does he have kids.
"Joists flex under the weight of foot traffic and furniture above"
Deflection in properly framed floors isn't a problem
for drywall (L/240).
4. DIY guy wants to strap his ceiling because the electrician ran cable
under the joists. The only responder to suggest he should strap the
ceiling says he's "no expert" and is just "under the impression" that
strapping is a good idea.
5. DIY guy wants to know whether to strap or not. Respondent says:
"Strapping is usually used to fix defects in the framing - joists with
too much span or uneven. If the joists/rafters are uneven, shimming the
strapping will help to level it out. It can also be neccesary to allow
for more insulation and/or air space for ventilation. Attaching directly
to the joists/rafters is the most common method."
6. Duplicate of #1. Yes, the same exact article.
7. Someone asks a question about the strapping in the video in #2. He
hasn't ever seen it done before. The only response is an incorrect guess
that he's talking about hat channel.
8. Same TOH video as #2
9. Guy wants to strap to fix an out of plane ceiling joist problem.
Professional drywaller suggest RC channel rather than wood strapping.
Another concurs. OP says strapping and shimming is a pain.
#10 is Yahoo! Answers. Someone asking if 32"oc is too much of a span for
drywall. I'm going to guess that one of the answers is yes, and that he
should install strapping.
I did a bit of looking around myself and didn't find much suggesting
strapping is routinely done for any reason other than
Tevyetradition... TRADITION! /Tevye
I did find one actual building professional who says that 1x4 strapping
is better than bridging for reducing floor bounce. But that's a fix for
a problem that shouldn't be present in new construction, not a way to
get a better ceiling.
As for truss lift, I don't see how strapping would help with that. If
the strapping is attached to the truss, and the wallboard is attached to
the strapping, it's all going to move together. How is that different
than if the drywall were attached directly to the truss?
I found one reputable guy who says strapping helps with the truss uplift
problem, but it's clear from his explanation that the strapping is done
_before_ the non-load bearing walls are framed, and that the top plates
are attached to the strapping rather than the trusses. I can see how
that would help as long as the strapping wasn't attached to the trusses
near where the top plates where attached to the strapping. But that
would _not_ apply to cases where strapping was applied after the
interior walls were framed, which is what you appear to be advocating.
The answer to truss uplift is floating the corners and/or roof-truss
clips. At least, that's what the engineers, building scientists, and
gypsum association say.
I'm not aware of any building codes nor wallboard manufacturer's
specifications which recommend or require strapping. I never hesitate to
point out that codes are minimum, rather than optimal, standards, so I'm
not claiming strapping might not have it's advantages. I just don't
think it's necessary to strap to get a high quality ceiling, and I think
that's pretty much the consensus opinion.