I am asking this question here because I know there are a lot of excellent contractors and engineers here and I wanted to get your professional opinion. My wife's office building has had repeated issues with the roof sagging significantly (like ceiling tiles falling out of place) from snow (we are in RI), and her boss has called their landlord and he said he checked it out and said it was ok like that, but for there to be a deflection of a couple inches, seemingly right next to a column, doesn't seem right to me.

In addition I found a FEMA snow load saftey document which says if any sagging is noticed it should be immediately evacuated: http://www.fema.gov/media-library-d...ad_508.pdf

Tell me I'm not crazy and they shouldn't be in that building?

I am not sure why the attachments didn't show up but here are links to them:
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My office building (in eastern MA) has similar issues due to the ~50' span of the steel trusses. A couple of inches in the middle of a long span isn't a big deal, but 4-6" might be. In the 6 winters we've been here only once have they opted to clear the roof of snow with a crew of guys with shovels (who promptly dinged up the membrane roof in several spots, which had to be repaired later) but it looked a lot worse than your wife's pictures at that point.

The column in the picture is not structural, but most likely a phone & power wiring post, common in suspended ceiling office build outs that don't have partition walls everywhere power/phone/internet needs to go. This makes it a good measuring point for the amount of sag, and it's worth keeping an eye on if there is no melting before the next foot of snowfall. But steel is VERY springy and tough stuff. A couple of inches over a significant span isn't much to worry about.

Eyeballing the sag was the first thing I did when I came in this morning though. The wind made the loading uneven, with some significant sags in some spots, nearly none in others. There is an obvious "wave" in the suspended ceiling of our lab space (which is nearly the full width of the building). But I'm not worried. This location has seen over 5 feet of snow in the past 20 days, with no thaws of any duration in the mean time.

Posted By Nick on 10 Feb 2015 04:12 PM
I am asking this question here because I know there are a lot of excellent contractors and engineers here and I wanted to get your professional opinion. My wife's office building has had repeated issues with the roof sagging significantly (like ceiling tiles falling out of place) from snow (we are in RI), and her boss has called their landlord and he said he checked it out and said it was ok like that, but for there to be a deflection of a couple inches, seemingly right next to a column, doesn't seem right to me.

In addition I found a FEMA snow load saftey document which says if any sagging is noticed it should be immediately evacuated: http://www.fema.gov/media-library-d...ad_508.pdf

Tell me I'm not crazy and they shouldn't be in that building?

I am not sure why the attachments didn't show up but here are links to them:
0 1 2

Nick26,
You are right they should not be in the building, a deflection significant enough to pop the ceiling tiles is near total failure, and when it comes down it will be catastrophic

One spec I have seen on some steel frame truss building that I had issues with a few winters back was allowable deflection of L/240. So a 20 foot building would be acceptable to deflect 1".

What is the unsupported span? An Mtrentw mentioned, all trusses have an allowable deflection under load. Length of span divided by 240 or 480 are common specifications. If it was a 50' span under L/240 it would be allowed to deflect 2.5" from no load to full designed load.

I think Dana1 is right and that is a wiring chase and not a structural colunm. You would have to pull a ceiling tile to be sure, but if it were a structural colunm it sould be the last place you would see movement...

It is probably a case of the suspended ceiling installers attaching the ceiling perimeter frame TO the chase when they should have hung it from the ceiling like all the other mid span ceiling framework. That would have allowed the suspended ceiling to float up and down alongside the walls of the chase/colunm as the trusses deflect. If they did this, the chase could then be marked to show the roof defletion and indicate when the roof load started to reach and perhaps exceed design loads("When the ceiling reaches this mark, LEAVE THE BUILDING IMMEDIATELY!")

Triangular wood framed roof trusses do this also on the bottom chord of the truss under load, and as the top chords expand and contract due to temperature changes. Because of this you don't hard attach the interior/non structural walls to the bottom of the trusses. You instead use a slotted clip that allows the bottom chord of he truss to move up and down. You also need to plan the wall locations and drywall install so as to not hard attach a drywall corner at a chord-wall union. If you do the drywall will crack and or buckle as the truss repeatedly deflects...

It probably depends somewhat on how the tiles are held up and what they're hiding. There might be old plaster or sheetrock ceiling under or above them, however you want to describe it. So there's no real way of knowing how soon anything could fall down. What kind of roof is it? Is there an attic between the roof and the rooms with the acoustic tile ceilings? How big are the holes in the roof? Too many variables for us internet friends!

I am in the process of saving a currently unlivable old house with a leaky roof. Chunks of plaster fall off the ceiling. You wouldn't want one to fall on your head.

Sometimes small leaks in roofs can be temporarily fixed by applying a liberal swath of roofing tar over the leaky place.

Good luck!