Replies

1. 
   WayneL5 | Feb 09, 2005 06:15am | #1

   Blocking between the joists can help because it helps distribute the load to more than one joist.  But you have to rip up the floors for that.  If you were going to go to that expense, I'd consult an engineer.  Short of ripping up the floors, there is little you can do.

   It's not the fault of TJI joists.  The builder could have selected any amount of bounciness he wished to from the tables the manufacturer supplies.  He apparently chose the "economical" table to design from.

1. 
   tumeric | Feb 09, 2005 06:50am | #2

   The look is great. How did you undermount the sink?

2. 
   flivver | Feb 09, 2005 04:50pm | #3

   thanks for the info. that's a bummer, I can't rip up the floors. Oh well.Could you think of another solution? I've already consulted an engineer and he suggests bracing as in old houses.

2. 
   zendo | Feb 09, 2005 05:19pm | #4

   Can you get to them from underneath, that would be the first thing I would do.  Ceiling or basement is much easier than floors.

   -zen

1. 
   flivver | Feb 09, 2005 06:13pm | #5

   Yes, I can. What do you suggest. The builder already put up a bunch of 2x6s to reinforce, but that didn't work

3. 
   panelguy | Feb 09, 2005 09:27pm | #6

   Deflection is not simply L/360 or L/480 - there is a whole lot more:

   TJI use a pro-rating system to evaluate floor performance.  Every time you get a layout from your local distributor they can evaluate the performace of the floor and can give you a projected rating.  Your floor can be evaluated with a poor pro-rating but can still pass code requirements.  I suspect that your builder wanted to cut costs and ignored the pro-rating.  In Canada, where we build, vibration-controlled criterion are written into the building code.  Some things you may want to think about: what kind of sub-floor was used and how thick is it (there is a difference in performance between high-performace panels like Advantech and regular OSB products); you may have to add some load bearing walls below to reduce joist spans; make sure a ceiling is directly applied to the underside of the joists (either strap or drywall); evaluating floor performace can be very subjective and each person may have a different view on what constitutes a bouncy floor.  Unfortunately, the easiest method, bridging and blocking, does little to enhance floor performace and TJI acknowledges this fact.  Good luck and let us know if you come up with any alternative solutions.

1. 
   zendo | Feb 11, 2005 08:15pm | #7

   Im not sure whats downstairs, but if you can the best solution is direct support.  The load bearing wall is a great idea.  Another is to run a beam across the bottoms of the joists held up by posts or lolly columns.  Both of these suggestions need to be run perpendicular to the span of the joists.  That would take out pretty much all the bounce. 

   The problem here is that the spans are to long for the rating of the TJIs.  They are probably built to code, but thats disappointing.  Im going to contact a few members in breaktime that know a lot about tji members. Im not sure if it is even allowed with the warranties to "sister" onto the beams, and unless you follow through from sill to sill it probably wouldnt help. 

    

   -zen

1. 
   flivver | Feb 15, 2005 03:38am | #8

   any other suggestions. my builder's rep disavows any responsibility and says if he trries to fix the bounce it's not because there's a problem or it wasn't done right; it's because hey're "good guys".The TJI rep also says everything was done "to code"

1. 
   highfigh | Feb 15, 2005 06:47am | #9

   How long are the joists? There was a table posted today in another thread that shows the allowable span. Building code is one thing, the manufacturer's recommendation is another. Since you have access to the underside, reducing the span is the best choice. If there's enough height below and you can give some up, maybe a pilaster on opposite walls with a beam, centered, supporting the floor.
   "I cut this piece four times and it's still too short."

1. 
   flivver | Feb 16, 2005 05:46am | #10

   Thanks for all your advice. They were here again today and put some TJI pieces as braces, last week they put lengthwise boards and nailed and glued them to the underside. nothing has worked . the dresser handles still bounce. It appears they've done all they will do for now and I'm getting pretty frustrated. I think other folks in the development are having the same problem and have had the same lack of admitting thats it's either the installation, or the TJI joists that are the problem. I don't think floors have to bounce, but I'm not a builder nor do I have any real building skills and of course, they don't want to admit to any issue that they might be at fault.It may be that the joists need a vertical support, which I guess could be done and if it didn't work, could be taken away. By the way is that a "pilaster" that I'm describing above?

    

2. 
   saulgood | Mar 06, 2005 03:13am | #11

   1.I'm not sure if this is the same as "bridging" mentioned above, but blocking effort will be much more effective if the blocks are installed in a straight, continuous line and then connected across the bottom with steel strap.
   2. maybe you should get some new handles for your dresser.

3. 
   flivver | Mar 06, 2005 05:28am | #12

   thanks for the advice. The floor joists in my basement now are a mess of boards, braces etc. the floor still bounces and even my son suggested double sided sticky tape  or maybe a thin picture frame corner bumper. I'm so disgusted with the whole thing . First the builder's rep said nothing could be wrong it's according to code etc, etc and then they tried all those " sister" braces and what not.  If they had done it the way the TJI people said in the first place, or had not had such long runs of joist , it wouldn't have happened. well, so much for modern innovative construction material.

    

4. 
   mach1 | Mar 15, 2005 07:10pm | #13

   I'm not sure what method they used to bridge & brace your floor but check out FHB, Nov. 2004 (No. 166). They show a method of bridging TJI's on pg. 104 that looks to be the only way to go.  

5. 
   manimal | Mar 15, 2005 08:36pm | #14

   I've got a feeling that whoever built the floor didnt refer to the good old fashioned local code book.TGI'S are a great product being able to span long distances without supports.but even they have their limits.I would check to see if the supports are within code as far as spacing,if they are then i would consider applying 2x6 or 8's or even 3/4 ply on both sides of the joists(glued and nailed like crazy)then i would put blocking or bridging in.it sounds like you really have to beef them up or add more support to them ether way the builder should have done that.

4. 
   fredsmart48 | Mar 26, 2005 03:30pm | #15

   From what I know there are only two ways to fix your problem.

   One is to buy more TJI that are 2 to 4 inch deeper now place them half way in-between the original tji.

   The problem with that is all the wire, plumbing and heating that will be in the way and would have to be redone.

   The other way is to put a support beam at right angle to the floor joist and support it at both ends and down the length of the beam as need. There are three ways that come to mind to this.

   Is a load bearing wall in the middle of the span. Where you put a double plate on top and 2x right underneath the floor joist one plate on the floor. If you do that you lose the big open space and create small rooms.

   Is a beam that supported on each end with a steel columns and a few in-between. The end columns. If you do that you loose head height.

   Is the same as number 2 but floor joist are cut and the beam is put in the space where the joist were cut and the beam is lifted up to support the now shorten floor joist. You still need the support columns for the new beam but you don’t loose as much head clearance.

   1# will need to be built so that the wall picks up the load of the floor joist and transfers it to the basement floor.

   #2 #3 will need an engineer to size the beam and where to put the columns.

   If you want get the builder to pay to fix the bouncy floors you will need proof that it was built wrong and that will take a engineer to prove it with numbers that the builder over taxed the design of the floor. You can not take the word of some tji salesman or their design person telling you there is nothing wrong. After you get the numbers from your engineer. get your contract out and see what is specked out for floors deflection if any thing at all. Don’t be surprised if it is not in the contract. Also look to see what modle Tji is called for in the contract. Again it might not be there. There are several different TJI that will have the same width but the top cord and the bottom cord will wider then others make sure the one that they use is the one in your contract.