# Houses with 48" on-center 4x6 joists?



## Bondo (Dec 8, 2007)

> over 4x6 joists 48" on center.


Ayuh,... 
I think you'll get more bang for the buck by closing up those 4' Centers.......

How about a run of 2X6s to bring it to 16" or 24" centers,..??


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## juryduty (Mar 10, 2008)

*Here's a picture*


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## Daryl (Aug 20, 2006)

i like Bondos idea filling in the "16 OC's" with 2x6. 

prior to installing the 2x6 i would mark my layout and install hangers on one side of the bay. next i would suggest a bead of subfloor adhesive on the top of each 2x6 to be installed. Install hanger on remaining end of each joist as you install them.

-Daryl


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## Daryl (Aug 20, 2006)

or... if you so choose to run your 2x6 joist perpendicular to the subfloor (as you should)

hang a dbl 2x6 at each post that the 4x6 is sitting on, and then hang your 2x6's on the dbls 

and DONT FORGET to insulate vapor barrier up if there is living space above.


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## juryduty (Mar 10, 2008)

*Ok*

So I should run 2x6's perpendicular to the existing joists, without any additional footings (can't easily pour new concrete footings anyway). How many 2x6's should I run? Every 2' or so?


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## Daryl (Aug 20, 2006)

at each post that post down the beam to the footing... install a dbl 2x6 joist on the beam. Then install dbl hangers on each end. then measure from the beam 16" and make a mark, then 32", then 48" then make an X on the side of your 16" mark that is closest to the beam. square this mark on the beam with a speed square or combo square. then install the joist on the X so there will yield a spacing of 14.5" in between the beam and the joist.

-Daryl


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## Ron6519 (Mar 28, 2007)

Where do you live that this construction would be to code?
Ron


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## juryduty (Mar 10, 2008)

In the San Francisco Bay Area (East bay). The house is part of an 1000+ home development built in the 1970s. Is it considered "cheap"?


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## Ron6519 (Mar 28, 2007)

juryduty said:


> In the San Francisco Bay Area (East bay). The house is part of an 1000+ home development built in the 1970s. Is it considered "cheap"?


California probably currently has the strictest structural requirements in the U.S. Maybe the '70's were a little more mellow.
Ron


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## LawnGuyLandSparky (Nov 18, 2007)

Is the entire house like this, or is this an addition. That work doesn't look like it's 30 years old.


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## juryduty (Mar 10, 2008)

The entire house is like this. The house was built in 1972. You're right, it doesn't look 36 years old and has held up well. The problem is that if you're standing in a room and someone walks by you at close range, you can feel the plywood span give a little bit. This is what I'm trying to fix -- I want to make it feel sturdier and hold up under hardwood or laminate, maybe tile, etc.


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## joasis (May 28, 2006)

I just thought I have seen everything. 

As suggested above, add joists.....and if it wasn't clear from above, the easiest way to tackle this would be to run them 90 degrees to the main joists...that makes the added joists like 44 inches long, and if you do 16 or even 24 on center, it will add a lot of rigidity to the floor. Looks like you have plenty of room to work in.


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## Wanttodoitright (Mar 17, 2008)

I have the same problem in the addition that was built on my house. The addition was put on about the same time that your house was built. The rest of my house looks exactly like yours underneath, but my subfloor is 2"x6" T&G, and is VERY strong, with no flex.

My addition, however is the same specs as your house, including the plywood (called plyscord back then), but they DIDN'T put piers in to support the span.  It is 11'6" by 23'. My 4x6 beams span the 11'6", with no support in between!

MY question to everyone is can I jack up the now-sagging beams and put posts and pier footings underneath? 

They only sag about 1/4" - 1/2", which has caused a slope in my floor. Whille under there, I want to add the 2x6 joists mentioned earlier to eliminate all of the flex in the subfloor, as I am going to do 16"x16" porcelain tile in one area of the addition.

Also, underneath the addition is the original concrete patio that was the backyard. Will I be able to set the pier footings right on top of this concrete?


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## juryduty (Mar 10, 2008)

I am considering simply adding another layer of 1/2" plywood, screwed and glued to the floor, then a layer of nailed hardwood. Can you folks really tell me that this would not strengthen the floor considerably? It seems like an easy, straightforward fix. The problem is the span, right? And this strengthens the span a lot.


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## Daryl (Aug 20, 2006)

If I got this correct...

Jury... You _*asked *_if adding a layer of 3/8" plywood would be sufficient in your first post.

Since your 1st post you were advised by 3 separate individuals to introduce more framing to the equation.

a full 2 weeks go past

In your most recent post you are now "considering" adding only 1/8" thicker plywood than you had originally _*asked *_about, but mention nothing about the framing that was so highly suggested.

What makes you believe that 1/2" plywood is _*THAT*_ much more of a benefit over adding framing?

All things considered, we all want to get the task at hand completed as efficiently as possible.

At what point do we take someone’s suggestion that has "Been there done that?"

Just my .02, Please reconsider your approach to end at a job well done for years to follow.


Regards,

Daryl


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