# Bouncy Floors



## greenley (Jan 6, 2006)

I recently built my own house operating as owner-builder. I'm an electrician by trade, so please forgive my ignorance in advance... We used trusses for the floors and they span 22' while being spaced 19" on center. It seems like my floors bounce more than any other house I've been in, and I've been in a lot. The kitchen cabinets shake, and all these heel-walkers (my wife and kids) sound and feel like a stampede going by. Are there any easy fixes or ideas for getting rid of the bounce???


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## neolitic (Apr 20, 2006)

greenley said:


> I recently built my own house operating as owner-builder. I'm an electrician by trade, so please forgive my ignorance in advance... We used trusses for the floors and they span 22' while being spaced 19" on center. It seems like my floors bounce more than any other house I've been in, and I've been in a lot. The kitchen cabinets shake, and all these heel-walkers (my wife and kids) sound and feel like a stampede going by. Are there any easy fixes or ideas for getting rid of the bounce???


Assuming that they are
properly sized, I would have
two rows of bridging for that
span.


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## greenley (Jan 6, 2006)

Need more input... remember I'm an electrician, so I need answers in layman's terms...:blink:


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## neolitic (Apr 20, 2006)

greenley said:


> Need more input... remember I'm an electrician, so I need answers in layman's terms...:blink:


Let's start with dimensions
and pix. :thumbup:
Specifics will help get specific
answers.
Bridging on truss joist would
probably look like "X's" between
the joist.
Meantime Google bridging.


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## SelfContract (Dec 6, 2007)

Also, pix of column supports too, if any or lack of??


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## critter (Nov 27, 2008)

greenley said:


> I recently built my own house operating as owner-builder. I'm an electrician by trade, so please forgive my ignorance in advance... We used trusses for the floors and they span 22' while being spaced 19" on center. It seems like my floors bounce more than any other house I've been in, and I've been in a lot. The kitchen cabinets shake, and all these heel-walkers (my wife and kids) sound and feel like a stampede going by. Are there any easy fixes or ideas for getting rid of the bounce???


Hey, Greenly!
A frustrating problem to be sure. If you go the bridging route, you will improve (lessen) the bounciness, but it will probably still not be acceptable to you. If this is a first floor over a basement area, your best fix may be to install the support girder that you were trying to avoid by using trusses. 
Another possibility (check with manufacturer) is to plate the sides of the trusses with osb, glued and nailed as per their suggested nailing schedule for such a reinforcement. Make sure your fix does not conflict with their engineering in any way and direct these questions discussed to the truss manufacturer. There is where your safest, surest answers lie.
If you used I-joists, there is some possibility of adding material to the web (center vertical) section of the I-joist. Again, refer all these ideas to the manufacturer - don't take our word(s) for the best fix.
-Best Wishes.


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## neolitic (Apr 20, 2006)

The only thing that stops horizontal
defection is bridging.
Whether truss, I-joist, or dimensional,
The strength is vertical, not horizontal
(side to side).
If he knew what he was looking for
he might be able to see them twist
under load. 
I have.
Bridging may not get all the vibration out
of a huge membrane, but it will stiffen it
and make the joist work as a unit.


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## rbsremodeling (Nov 12, 2007)

neolitic said:


> The only thing that stops horizontal
> defection is bridging.
> Whether truss, I-joist, or dimensional,
> The strength is vertical, not horizontal
> ...


Every time I read one of your posts. I get the impression you've done this carpentry stuff a few times before:laughing:


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## neolitic (Apr 20, 2006)

rbsremodeling said:


> Every time I read one of your posts. I get the impression you've done this carpentry stuff a few times before:laughing:


Sometimes I think most of
what little I know comes from
fixing other people's ups. :whistling:laughing:


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## Paulie (Feb 11, 2009)

I got to diagree. Bridging is not the ONLY THING that stops deflection. I agree bridging is a solution that couldn't hurt without more info. A support truss is another possible solution. The bouncy floored electrician said his kitchen was a problem, not to get down on the plumbing trade but I've seen more than one plumber sawsall a knotch or two in the floor joists.


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## loneframer (Feb 13, 2009)

I agree with the double row of criss-cross bridging. I would use 1x3 or 1x4 clear pine. Before installing look for sag in the joist, if there is,according to whats above you may be able to take some of the deflection out.Don't attempt this if there are tile floors or cabinets above, only if its open space.Otherwise I would spread the rows of bridging 2 feet each side of centerline of span,keeping them in a continuous line the entire width of the building, this should help tremendously. You may still feel a spounginess to the floor which may be due to 19.2 inch centers, the subfloor is probably deflecting between joists. The bridging will help with the bounce because it forces all joists to share concentrated loads.When attaching bridging in this situation I would hold bridging flat against side of truss and fasten top through short point of angle cut, then fold up to contact other joist, tap up to snug it in and fasten securely, being careful not to split.


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## neolitic (Apr 20, 2006)

paulie said:


> I got to diagree. Bridging is not the ONLY THING that stops deflection. I agree bridging is a solution that couldn't hurt without more info. A support truss is another possible solution.





neolitic said:


> *Assuming that they are
> properly sized,* I would have
> two rows of bridging for that
> span.


We are talking about two different
kinds of deflection here.
The beam deals with one,
the bridging another.

If he has a 22' span, it needs
bridging.


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## D.Foster (Sep 13, 2008)

paulie said:


> I got to diagree. Bridging is not the ONLY THING that stops deflection. I agree bridging is a solution that couldn't hurt without more info. A support truss is another possible solution. The bouncy floored electrician said his kitchen was a problem, not to get down on the plumbing trade but I've seen more than one plumber sawsall a knotch or two in the floor joists.


 A plumber shouldnt need to notch a floor truss, he doesnt have joists.And i think bridging is the way to go, esp for head room too. Another truss will be a head target:thumbsup:


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## Paulie (Feb 11, 2009)

Fair enough, my bad I jumped over the horizontal part. My other question would be of the code man letting a 22' span with a 19" OC go with no bridging.


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## Mike772 (May 16, 2005)

I build with floor trusses, maybe I can help.

22' should be no problem for floor trusses. I've clear spanned 32' with no problems and zero bounce. Granted I had them at 16"oc, but the original plans had them at 24"oc, my point is they will be engineered for your application to work. By me reducing the spacing, I reduced the bounce.

Floor trusses don't require "x" bridging, atleast in my state. They do require strongbacks. Continuous 2x6's nailed to the vertical member (inside the trusses) of the floor trusses. So from truss to truss and so on, from one end of the house to the other a 2x6 nailed to the vertical member with a minimum of (3) 16d sinkers on each vertical. Check the paperwork that came with the trusses, there is usually an explanation and some graphics of what they want and what is required. 

Now, on my larger spans I increase the the strongbacks to every 5', which is every vertical member in the truss. I'm told by engineering that will decrease deflection. And it does. I've noticed that any bounce or deflection to be almost completely gone when I add that many. 

The real trick is to not let the other trades notch or cut up those strongbacks. Depending on the height of the trusses, it usually isn't a problem.


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## loneframer (Feb 13, 2009)

Mike772 said:


> I build with floor trusses, maybe I can help.
> 
> 22' should be no problem for floor trusses. I've clear spanned 32' with no problems and zero bounce. Granted I had them at 16"oc, but the original plans had them at 24"oc, my point is they will be engineered for your application to work. By me reducing the spacing, I reduced the bounce.
> 
> ...


 Strongbacks are the production answer to bridging. Without opening the side of the house up, strongbacks won't be continuous. The goal in either case is loadsharing of the joists. I would however recommend that any bridging should be inline with vertical members of truss. I won't build a floor system of any type without wood x bridging. It is tried and true.


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## MBS (Mar 20, 2008)

loneframer said:


> Strongbacks are the production answer to bridging. Without opening the side of the house up, strongbacks won't be continuous. The goal in either case is loadsharing of the joists. I would however recommend that any bridging should be inline with vertical members of truss. I won't build a floor system of any type without wood x bridging. It is tried and true.


I have to say that loneframer is right on the money here with the proper way to frame floor trusses. :thumbsup: Strong backs will make a huge difference and is often overlooked as unnecessary framing to the novice framer. Or they are planned for installation on a rainy day, then they are forgotten and the trades get in there and run their goodies which makes putting the strongbacks in almost impossible.


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## cleveman (Dec 28, 2007)

Original Poster:

Out of curiosity, were the floors bouncy when the house was stocked with sheetrock?


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## greenley (Jan 6, 2006)

You carpenters are a loquacious bunch - thanks for all the feedback. I think I'll try the strong back idea first, it actually falls within my limited carpentry skills. If that doesn't work, then on to the bridging. In regards to the strong backs, do they need to be nailed to each truss or did I read every five feet? Thank you kind sirs...


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## Warren (Feb 19, 2005)

Strongback needs to be nailed to every truss. Only problem is if the house is done (it is) then you will have trouble getting long lengths of 2x6 inside the webs. We generally slide them in prior to decking before we install our end band board. If you cant wiggle in at least 10 foot sections it probably wont help. Might have to try the bridging and maybe strap the bottom chords with a couple of 2x6 running across the bottoms. This will at least tie them together .


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## greenley (Jan 6, 2006)

Where exactly do I nail these strong backs? I've heard them being nailed to the webs - what part of the truss does that indicate - I have an idea, but I'd rather be sure of what I'm doing... Again please forgive my ignorance on the subject, the most carpentry work I do is drill holes in the studs for all my wiring.


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## neolitic (Apr 20, 2006)

It would be easier to know
what you've got if you can
post pix.
We are really just guessing
what your problem is.
Can you do that?


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## Warren (Feb 19, 2005)

If you have what we refer to as truss joists they are made up of 2x4's and metal gusset plates. If yours are made of osb with a 2x top and bottom we call those TJI's. if u have the truss joists, the stiffbacks are nailed to a vertical 2x4 member perpendicular to the joists. Generally all the joists will be oriented the same way so that these webs line up.


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## loneframer (Feb 13, 2009)

If bridging is installed properly, it is essentially the equivelent of building another truss perpendicular to the trusses. The more rows of bridging, the more trusses you are building to distribute load. Think about this, How much weight can you hang from a swingset? If you remove two legs it collapses. Bridging serves the same purpose, distributing load evenly.


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## cleveman (Dec 28, 2007)

Greenley,

Was the floor bouncy when the sheetrock was stocked?


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## greenley (Jan 6, 2006)

No pics -sorry - I don't have the tech-skills...
The truss system is made up of of 2x4's with metal gusset plates.
Don't know if the floor was bouncy when the Sheetrock was stocked.
I think I'm back to the bridging idea now - I do have a good number of metal plates that span between each truss - would those be sufficient bridging?


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## neolitic (Apr 20, 2006)

Are they maybe more like
metal straps?
Do they make "X's" between
the truss?


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## loneframer (Feb 13, 2009)

If you have metal bridging and it doesn't "ring" when you pluck it, you will get bounce in your floor. If you do wood bridging properly with clean cuts and tight installation you will definitely see a vast improvement. That is a promise.:thumbsup:


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## greenley (Jan 6, 2006)

The metal plates do not make an "x". They span from truss to truss and have tabs at each end for nailing to the wood.


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## neolitic (Apr 20, 2006)

Do you have a friend who can 
take pix and e-mail or load them to
your computer?
One pic looking down the joist bay
would save lots of guesses.......


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## loneframer (Feb 13, 2009)

greenley said:


> The metal plates do not make an "x". They span from truss to truss and have tabs at each end for nailing to the wood.


 That just sounds like strapping to prevent splaying out of joists, they will not distribute load.:thumbsup:


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## neolitic (Apr 20, 2006)

Does it look like this stuff?
http://www.theracker.com/products.htm


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## cleveman (Dec 28, 2007)

Greenley,

Put a piano or a bunch of buckets of water in the center of the span and see if it helps.

I've never seen a bouncy floor on the day when the sheetrock was stocked.


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## critter (Nov 27, 2008)

Mike772 said:


> I build with floor trusses, maybe I can help.
> 
> 22' should be no problem for floor trusses. I've clear spanned 32' with no problems and zero bounce. Granted I had them at 16"oc, but the original plans had them at 24"oc, my point is they will be engineered for your application to work. By me reducing the spacing, I reduced the bounce.
> 
> ...


I agree with you, Mike, floor trusses aren't even allowed to have bridging, according to some mfg'rs. due to misdirection of loading - and the ones that do usually specify location for bridging. I think that may be why they want the strongbacks - it forces the load-sharing to occur at the proper point in the truss webs. Usually, the truss web pattern means quite a bit more than the distance from span center. I would still be calling the manufacturer for THEIR fix, just to keep warranties good and my a$$ off the liability burner, should it ever come to that - even in my own house.


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