Sagging floor trusses in condo 7

[DaveNJ]

Hello,
I live in a condo in which the floor trusses deflect by as much as 1.5" over 6'. The two worst areas are at the ends of an interior, weight-bearing wall that runs lengthwise in the middle of the condo across the first floor. Last year after complaining to my HOA, their SE designed a fix that included jacking up the floor and then installing plywood gussets to the floor trusses. Unfortunately, the HOA was unwilling to jack up the floor for fear of collateral damage, but they did go ahead with the plywood gussets, which are now glued and nailed to the trusses.

Now I am still stuck with an unlevel floor and would like to find a fix. One contractor suggested removing the gussets, jacking-up the floor and then re-installing the gussets. I wonder how much damage this would do to the trusses. Another contractor suggested removing the plywood subfloor, shimming the top of the trusses and replacing the plywood. A third contractor suggested installing shimmed sleepers on top of the plywood and then adding another layer of plywood on top. Yet another contractor suggested first installing a wall in the finished basement and then fixing the floor from the top.

The HOA has washed their hands of the problem. I would have to sue them to get any further help from them. Since this is a condo, I am reluctant to invest large amounts in a fix, but on the other hand, think I need a level floor to sell the place. Any suggestions?
Thanks
Dave

P.S. The trusses are 12" high and the longest spans are 20'. The condo is 25 years old and there is no evidence that the floor has been sinking further over at least the last 10 years - no cracks in tile or walls.

 

[IsaacStructural]

A few thoughts:

1. I feel your pain dealing with HOAs, good luck on that front.

2. I don't like the idea of installing a load bearing wall below, this has the nasty tendency that in the future some other poor bloke will decide to "open up" the space below by removing the wall, and suddenly they have the problem all over again.

3. With the trusses already reinforced so that they can handle the new floor loading without further sagging, then building up and leveling from above is not the worst solution. it should be the least costly option.

4. If the joists are going to sag under the new loading, then I'd look to remove the gussets, jack up the trusses, and reinforce, sister, etc. as needed to get the floor system strong and stiff enough to not sag any more. Find a contractor and engineer experienced in this work, typically they will jack the floor slightly over level, then reinforce the trusses, and then finally remove the jacks, at which point the floor should relax down slightly and draw the load into the newly reinforced trusses.

5. I'd get a Structural Engineer out to determine which of the above is the best option. It seems like the association's Engineer might not be the worst option, only now you'll be footing the bill.

M.S. Structural Engineering
Licensed Structural Engineer and Licensed Professional Engineer (Illinois)

 

[MiketheEngineer]

I can tell you right now that 12'' high and 20' long is a real push. We seldom ever went that far - BECAUSE they creep (deflect) over the long terrm.

The simplest is leveling compound not sure what kind of floor finish you are looking for. It's like a rather thick cement type mix that you just pour and level. Takes a bit of a good eye and techniques but works well.

That said - you will need an engineer to see if the floor can accept the extra weigth. But the other solutions while quite good and commonly done also add weigtht.

The interior bearing wall? Does it set on top of the trusses running parallel or perpendicular?? Little sketch would be helpful.

 

[msquared48]

1.5" in 6 feet sounds ridiculous. That's L/48! Sounds like a framing design error was made in the original engineering design causing crushing somewhere, perhaps in multiple locations at the bearing plates. With no further deflections in the last 10 years, the crushing has probably stopped and achieved the needed bearing stress.

As for a fix - nothing easy here, and being a condo, it's a real can of worms. You have my sympathy.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[DaveNJ]

Thanks for the responses. I appreciate it.
The interior bearing wall is perpendicular to the trusses. Also, the trusses are mostly spaced 24" o.c. but some are as close as 12" o.c. There are two places where the trusses have been doubled up which I show in the attached diagram.

 

[msquared48]

OK.

Then that wall where the deflection is a maximum is acting like a bearing wall, loading the joist, where it was probably originally intentioned to only be a partition wall. The joist is just plainly overstressed. The framing for a partition wall is different than a bearing wall so these kinds of problems do not happen,

You need to get a structural engineer to open up the ceiling over the wall corner and see what's going on, as well as check our the floor framing above. I'm sure you will find more "goodies".

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[DaveNJ]

Actually, the shorter span trusses are generally 24" o.c. but the long ones are mostly 18".

 

[msquared48]

The shorter, deeper ones are probably transfer beams.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[BAretired]

If your repair involves jacking up the floor, you will be responsible for any collateral damage which you cause. I don't know how likely that is but the Home Owners Association has already expressed concern about it, so I would approach that idea with caution.

If you add significant dead load to the floor, you will cause more deflection and may overstress the existing trusses. I agree with Mike that you need to consult with a structural engineer to determine the best course of action.



BA

 

[woodman88]

"...Last year after complaining to my HOA, their SE designed a fix that included jacking up the floor and then installing plywood gussets to the floor trusses. Unfortunately, the HOA was unwilling to jack up the floor for fear of collateral damage, but they did go ahead with the plywood gussets, which are now glued and nailed to the trusses..."

If the trusses were not jacked up to releive the stresses in the truss, then the repair does very little IMHO to fix the truss. If you are trying to sell the place, then you are between a rock and a hard place. You know about the problem so you have to disclose the information to the buyer or get it properly fixed before selling.

If you do not have a copy of the repair than ask for one. If the repair work was not done per the repair drawings, ask them (the HOA and then the contractor) why before/and /or sending the information to the Building Official with your concern about a possible unsafe building condition.

Good Luck.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[DaveNJ]

Garth,
I see you are a truss designer, so your opinion regarding the ineffectiveness of the gussets has got me more concerned.
I do have a copy of the repair drawings, but in the instructions the SE left jacking-up the floor to the discretion of the HOA.
Dave

 

[MiketheEngineer]

Nice sketch - but w/o a full set of prints or a visit kind of hard tp prescribe from here....

 

[JedClampett]

Sell the condo to a skateboarder. Charge him/her extra for the bowled course.

 

[woodman88]

If the SE stated that the truss did not need to be jacked up before the repair and the HOA/contractor did the repairs per the SE drawings. Then HOA/contractor has fulfilled their structural responsibility. Who is (if anyone is) responsible for the sagging floor is a question. But you can now note in the selling papers that the sag exists but is structural okay per a SE. I would make the repair drawings part of the paper work (if you can) so if any problems come up later they can go directly to the SE on it.

Now I do not have a copy of the original truss design or the repair design to make a comment on. But some engineers would say that a floor truss designed for a 55psf (40psf live, 15psf dead) loading, I am assuming that the trusses were not designed with a partition load. If repaired without any live loads applied the truss would be only (15/55)100%= 27% stressed. So the gussets will be able to start working at 30% stressed. In your case you have a wall that weights, typically, 5psf at 8' high or 40plf for most of the length of the truss. You should look carefully the repair drawing loading to see what loads are accounted for. For a 24" o.c. truss you would have almost (40+2(15))/2(55) or 64% stressed truss at the time of repair. So the repair only starts working at 66%. This is a number game IMHO that I disagree with. I have always required the truss to be jacked up to relieve stresses.

As for adding some type of leveling material, as noted above, the repaired truss may require additional repairs. But the repair design may have added to the loading to account for this or maybe not.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[DaveNJ]

The drawings don't mention any loads, but as I look at the notes again they do say that the trusses should be jacked up first and that did not happen. You can see on attached.

 

[Ron]

Check your condo documents!! You are proposing to modify a common element (the structure). That is not your property...it is common property and generally you have no right to do anything to it.

You will have to force the HOA to take action, but you can't legally do it yourself under most condominium provisions.

 

[woodman88]

DaveNJ – Can't say I have seen anything like these drawings. No engineer seal or signature. No reason for the repair stated. No forces or loading to judge the repair. I would contact your Building Official about these drawings and the repairs already done. Here is a website

http://www.bedminster.us/index.asp?Type=B_BASIC&SEC={C10AAA12-DD19-4FE1-BD15-C3D4823D168D}

hope it is the right one. Go to the “Government” then”Department Directory” and click on the “Construction”. Which will give you this
“Construction Official
The Construction Official receives applications, issues permits, provides inspections, collects fees and answers code enforcement questions for all areas of construction - building, electrical and plumbing.
Contact this office for certificates of occupancy, sign requests, tree removal permits, driveway opening permits, change-in-use permits, developer's fee, and applications for historic appropriateness.
The Construction Official reports information to the Township, County and State, and to the Federal Bureau of the Census. Ken Rogers, Construction Code Official, 212-7000, Ext. 422.
Joe Haggerty, Technical Assistant to the Construction Official 212-7000, Ext. 421.“

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[Jc67roch]

I'm with MiketheEngineer and Woodman88. Cover your assets by getting all this included with your home ownership papers. Have an SE check that the repaired trusses can actually support the loadings required by the Building Code at the time of construction (that's the requirement). If they can, and can also support a little extra deadload, I would suggest going with the topside shim and cover approach.

 

[BAretired]

DaveNJ,

Is yours the only unit in the condominium that is having deflection problems? I would have expected other units framed in the same way to be experiencing similar issues. If not, what was different about your floor framing?

Note #10. on each of the three drawings specifies jacking the trusses 1/4" to 1/2" before installing the gussets. If I understand you correctly, that was not done, but in any case, such minimal jacking would not have alleviated a deflection of 1.5".

As Ron has indicated, depending on the condo documents, you probably cannot take remedial action on your own without the permission of the HOA. I do not believe the HOA is entitled to wash their hands of it. They will have to take appropriate measures to provide you with an acceptable floor

​

or face possible legal action.

BA

 

[msquared48]

Been implied here by BA, but it might be well to ask other owners if they are having similar issues with their units. The more units with issues, the more impetus for condo association to come up with a workable solution - hopefully avoiding the need for legal action.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com