Trusses

[po]

PLEASE HELP! One-year inspection - the ceiling in the master bedroom, hallway and garage - you can see the 'line' pressing on the ceiling in these areas from the trusses. Builder telling me this is normal - just shifting due to heat. I am afraid ceiling will crack - only one year old. Should I hire a structural engineer - I know nothing about building - have no one to turn to. Thanks so much - I had to have been 'led' here. This is so stressful - I have very hateful building people. Thanks, again

[giddonah]

that doesn't sound right. Sure, things will settle in time, but if things are settling that much in only a year, something is wrong. Definitely have someone check this out, and document every move and every phone call you make, names, dates, times.

[VALENT]

are you sure the line is not drywall joints? Trusses should not be settling through the drywall. Either these are joint lines(cosmetic problem but no biggie) or there is something going on that shouldnt be.

[po]

No, I can't say for sure, thanks for this. I will find someone to go up there and see. This is what someone else told me when I noticed them and the guy from the builder immediately defended the 'trusses' when I pointed out the line. This could have been a 'knee-jerk' reaction from him since almost every problem I brought up was 'oh, that is OK'. I will check this out, though, and come back to this forum.

[giddonah]

One quick indicator is whether the defects are 4' on center or 16". I'm starting to think sheetrock seams now. But that isn't normal either. (well, maybe it is normal, but it shouldn't be :wink: )

[montytx]

Maybe he forgot his rat runs and the trusses are moving a bit....

[Cole]

I bet some people are like "rat runs" what is that?

lol, finally someone that can understand my terms.

[Dragon]

You mean some people don't call them rat runs?

[po]

Thank you all for your replys. I take it 'rat runs' are needed for stability? If I addressed this with the builder what is the real 'term' I would use? I am in the process of sending a registered letter to the 'big cheese' and I will only have 'one bite' at him. Thanks.

[VALENT]

I think they would be the same as "strong backs". They are 2x6s or 8s that are nailed into an L or a U and then nailed to the bottom chord of the trusses in the attic and keep the truss chords from having any lateral movement. From your description, though, I dont really think this is the problem.

[Dragon]

No, a strong back is nailed to the rafter.

A rat run is nailed to the ceiling joists.

[R Birch]

Evidently the use and meaning of some construction terms is assumed differently regionally or from one jobsite to the next. I did some net surfing to find a Construction terms glossary and did not really see/find anything that defined the terms “strong back” or “rat run”. If someone has a link to a good online construction glossary I would appreciate it if they would share it.

I use the two terms above often and this is how I differentiate them from each other. A “rat run” is a single board (usually a length of 2/4) nailed to the tops of ceiling joists or truss ceiling cords to hold the position of these components sure and stable against twist or movement. They make an apparent attic “highway” for rats. I’ve seen rats use them in older homes too. I use the term “stiff back” or “strong back” to describe a “rat run” that has a second board (usually the same dimension as the joists) added to it (forms an “L”) for extra “stiffening” strength and flattening of the center of the room’s ceiling joists.

Since I typically place my rat runs at approximately 4’ o.c. across joist I rarely find it necessary to add any stiffeners. One of our framing inspectors told me this was the new preferred practice by the newer building code. However, I could not confirm this by searching the codes myself. On the other hand, I like it better and I have never been flagged for improper ceiling bracing for placing “runners” 4’ o.c. over joists since I started doing it that way either. Trusses will usually come with instructions for placement of the lateral bracing.

Truss roofs can move up and down with temperatures quite a bit from my experience. The movement can telescope through the dry wall ceilings. If this movement happens, once it cracks the tape joints, will probably reoccur on a regular basis. I have noticed that it is more likely to happen with tricky hip roof trusses systems where the trusses are different sizes and shapes and often have girders to hold up the perpendicularly placed Hip system. It also can be more of a problem with roofs that are hybrid stick/truss roofs. I have also seen homeowners store way too much stuff in the garage attic and cause problems too.

Po,

I do not think you need a structural engineer’s help on this yet, but if it will make you sleep better, by all means, hire one.

[giddonah]

http://www.construction-resource.com/glossary/

You could pm Rich to ask for new definitions. It would help him know what is needed.

[Joe Carola]

From where I'm from, a Strongback is what we put on top of the ceiling joists mid-span. A 2x4 on a flat and a 2x6 on edge nailed into the 2x4 and toe-nailed into the ceiling joist.

Joe Carola

[Dragon]

Yes I think this is one of those terms that varies from area to area.

I build them as Joe described, but call them rat runs if they are on ceiling joists. We then use the same construction method and attach them to the bottom of the rafter mid span (calling them strongbacks) and run bracing from one to the other.

[Rich]

http://www.construction-resource.com/glossary/

You could pm Rich to ask for new definitions. It would help him know what is needed.

LOL - I barely have time to read the posts here anymore let alone add construction terms..
Honestly though - I do need to finish up that page.. thanks for the reminder.

[Cole]

Do you want me to do it?

[Rich]

I call "rat runs" "rat tracks" - sounds a little better than a rat with diarhhea :)

[Cole]

I call "rat runs" "rat tracks" - sounds a little better than a rat with diarhhea :)
:lol: :lol: :lol: