Floating trusses - Contractor Talk - Professional Construction and Remodeling Forum

Snobnd · 02-18-2009, 09:27 AM

Floating trusses

I helped my painter at his house built back in the early 1970, the problem is that the builder floated the trusses over all interior walls- A slip clip was installed at a few points on barring walls.

The drywall corner tape is pulled away on most of the walls-
The gap in-between truss and wall is at least 1/2 inch in winter-

Question: What was the point of floating the trusses?
In all the framing jobs (9 years out of 30) I have never even heard of guys doing this - Have you guys seen this type of connection ( or was this builder a flipping %&^%^%)

I cut the tape, caulked the gap and installed a picture molding around the walls.

cleveman · 02-18-2009, 09:36 AM

I haven't used the search button on this, you might want to try it.

This may be an interesting thread because there is some controversy about what to do with the trusses over partition walls.

I've heard of:

1. Nailing them tight.
2. Some sort of clip or a block on both sides of the truss.
3. No fastening whatsoever.

Let's see what kinds of replies you get.

mics_54 · 02-18-2009, 09:38 AM

Trusses shouldn't be attached to interior walls unless the truss is designed to sit on the wall at that point.

Is your house on a concrete foundation/floor?

Do you live in a northern climate?

hatchet · 02-18-2009, 09:49 AM

I think the problem with the drywall is more a function of the drywall not being installed correctly versus the trusses not installed correctly. Up North we clip all trusses to intermediate partitions.. especially on long spans. There is all kinds of information on how to drywall to accommodate truss uplift.

jaros bros. · 02-18-2009, 10:04 AM

Occasionally, you can get some poorly designed trusses and there can be warranty issues with the truss company. I've seen truss uplift of over 3 inches in one house. It isn't very common to be that extreme though.
Trusses shouldn't be fastened unless they are designed to be fastened. Use of the clips is essential to the truss functioning properly. Some of the issues of truss uplift are caused by the chords absorbing moisture or drying out during the winter.

bigjohn316 · 02-18-2009, 10:19 AM

Most truss companies that we use here in Winchester VA area supply instructions on proper placement of ceiling drywall in order to counteract the affects of truss chord uplift. They recommend the use of "F" clips on all interior walls. Clips attach to edge of ceiling and are attached to wall plate and ceiling drywall is not to be fastened within 16" of wall. This should allow truss chord to move and not disrupt corner.

Snobnd · 02-18-2009, 10:20 AM

The drywall was installed correctly. This is on a 2nd fl 4 bdrm house. in the winter the truss will rise 1/2 to 7/8 above the plate. When this happens cold air will leek into all the rooms from the cracks. It is insulated with 10" fiberglass. I was taught to nail all the trusses I have installed since 1975 to keep the truss in place, and to keep the truss from moving to much, otherwise all the screws/nails will pop all over the place.

I have done framing Calf, Fla, Vermont, Even Canada.
I have just never came across this problem before.

Thanks for the info guys.

Lets see what the rest of CT says .
(should be interesting)

reveivl · 02-18-2009, 10:59 AM

Nailing the truss where it is not designed to be nailed is a no-no. Besides, it won't help, something is going to give. Use the clips and 'float' the ceiling drywall the last foot or so.

strathd · 02-19-2009, 10:01 AM

Round here every truss package comes with literature and diagrams on how to install truss clips. I have explained to GC's the benefits of using them. They usually say makes sense but just nail them down.
They probably dont want to buy the additional drywall clips that are needed for this system. Then have to explain it to drywallers. I live in a town of 35,000. My own house that I built 12 years ago is probably the only one in town with truss clips. Not one crack to this day.
Climate has a lot to do with truss lift. 0 degrees in the attic 70 in the house, somethings gonna want to move.
In the 80's I framed in phoenix. Houses were built on slabs. Interior walls were built with shorter studs than exterior studs. Cant remember the lenth. It came out like a 1/2'" to 3/4" gap between the top plate and the truss. They did'nt want trusses bearing on walls. Dont know if they still frame that way now.

**framerman** · 02-19-2009, 05:26 PM

no nailing to interior partitions unless specified. Trusses are designed to move. We did a hotel many years ago, there was a 60' run, can't remember the pitch, but I think it was 6/12. The design included a 3" deflection. We had to build our walls 3" lower than the bottom of the truss.

The simpson clips are the right thing to do, I guarantee it. The sheetrock nailing is supposed to be held back 12" I believe from the face of the wall.

Your 1/2" gap is something else, more than likely settling or shrinkage. I love the debate of truss uplift. That'll get this place going.

trusstech · 02-23-2009, 11:08 PM

Here is the TTB for Partition Separation Prevention and Solutions. ttb%20partition%20separation.pdf

Trusses should only be toe nailed at bearing locations. For partitions use the slotted clips to attach the truss to the partition, and then either use drywall clips or blocking, but the important thing is to not attach the drywall any closer that 16" to the partition for the ceiling and 8" on the walls.

Willie T · 02-24-2009, 06:49 PM

It was only a day or two ago that a drywall contractor on another forum came real close to calling me out as being among "cheap builders" for the use of "F" clips. I considered the source, and just kind of let it go. All he ever knew, I guess, was to nail it all up solid, so anyone trying to do anything else must be trying to get by on the cheap.

mics_54 · 02-24-2009, 06:56 PM

This is why "continuing education" is required for general contractors. Illness isn't caused by "demons" any more either.

Willie T · 02-24-2009, 07:08 PM

Well, to be fair to him, I think he felt we try to "cheap out" by not deadwooding all our partition walls.

My reason for not doing that is because I am death on partitions touching a truss... anywhere. And my top plates are always anywhere from 1/4" to 5/8" lower than the truss bottom chords. I don't like the dip the loft takes to meet top-plate-nailed deadwood that much lower than the truss. "F" clips eliminate almost all of that.

mics_54 · 02-24-2009, 07:13 PM

That being said...both times I checked out the truss heaves that were supposedly causing big problems with the cieling joints ended up being setteling floor beams in the crawl space.

Willie T · 02-24-2009, 07:25 PM

Ya know, I was just sitting here idly wondering exactly how much of my money Simpson pockets with all the clips and ties that I just go along with, either because I have to for code compliance, or because I want to have a little better looking job. Need to separate out some of that stuff one of these days to satisfy my curiosity. Hell, it might give me a heart attack.