I own, (or possably it owns me) a 30 yr old house. I have currently the old 2X6 T&G subloor over 4X6 beams at 48″oc.
The problem is my wonderful wife is dead set on 12X12 Tile in the kitchen and bathrooms…
the question is do I simply add a layer of 1 1/8 T&G plywood qlued and screwed down over the 2X6 T&G in order to get the stability needed remove the flex in the floor. Or do I remove the 2X6 T&G and add 2X10 Joists in between the 4X6 beams and then add 1 1/8th plywood and go from there or something else?
Replies
Why do you need to remove the T&G to put extra joists underneath? If you can do that, it will add a lot to the stiffness. You won't have to put such heavy plywood on top of the T&G. You'll need some of that thickness for durock and tile, unless you want a floor that's 2 inches thick.
Just adding heavy plywood on top will probably not decrease the bounce all that much. I think you do need to do something underneath, like taller joists.
Keep adding weight to the structureal system you have now will just increase the deflection while raising the finished surface. It may hurt but restructuring is the way to go and if you are trearing out 2x6 to do it, then you make room for the advantech and concrete backer board and tile
Excellence is its own reward!
Frankly I agree with both of you, Weight does not = stiffness.
So I remove the whole thing and I am left with 4X6 beams that are 48" OC that I can hang joists off of... would a "best practice" in this case be:
2X8 joists would seem to be the answer hung off the 4X6 beams. should I hang them @ 12"
keep in mind that I can't put 2x10's in because the space between the bottom of 2X10 and dirt would be 16" (the building code in the area is 18" and I have a good inspector but he won't go for that.)
Any other ideas?
2x10 is about twice as stiff as 2x8. Get out your shovel and bucket. If my inspector was that picky, I'd dig out 2 inches.
Adam,
I don't think you gain anything by hanging new joist off the 4x6's.
I would add a 2x6 in between the 4x6's and then add a 6x6T and piers to cut the span in half. Treated can be closer than 18".
Top off with 1/2" cdx and hardie depending on height issues.
KK
Run the new joists parralel to the beams not hung from them.
The 4x6 and the 2x6t7g makes up a total system. You will be building a new system in around them, partly using them for help.
I am blinded by not seeing all the conditions but it doesn't seem too hard to dig out two inches of dirt from under once you have the t7g up and 44" wide chanels openned up.
Excellence is its own reward!
WOW, I am incredibly impressed with the amount of support anybody can get at this forum, and then there is the speed issue...
Thank you,
Some things I do know about computers, fine woodworking some things I do not... building, rebuilding houses It's a very good thing my wife really loves me, as I have a major tendency to not just merely over build but to imagine the stresses that 100 years put on something and then build to that spec (or what I imagine that to be). sometimes this means doing it over but.... I am sure that nobody here has ever done that before.
Well it looks like I am going to be spending more time on the kitchen floor than I thought.... oh well, now where did I put my bucket and shovel.... :-)
I actually called my inspector and he came over for coffee.... I almost fainted when he said yes...
I had taken some pictures of the sub-floor under then house and showed him those and some ideas of what I wanted to do and asked him what he would recommed well he said:
Dig some out
Add some piers like you would use for a deck
PT lumber up to 3 new beams running length of kitchen 16” oc
one right in middle, others right along front edge of cabinets (support for tile)
the cabinets get supported by joists running between the 4X6s
1 1/8 ply plus ¾ ply over to make up height difference (All T&G glued and nailed down)
hardibacker board
tile
done
now from an over builders perspective, this sounds good,
But does sound good to you?
any other sage advice gentlemen?
"Dig some out",,, well I would, and then dig some more, you know the drill, while I'am doing it, and I've got the floor tore up, ya, just another 100 more shovels fulls, be done by lunch. Don't forget 12" minimun under any beams.
well I must say... thanks for all your help on this issue.
I got the subfloor in... I only get a 1/32nd deflection with a 400 lb weight over the 20 length of the kitchen. That should be good enough
on the 10' width.... I can't measure any deflection at all
Christmas is coming..... should I buy the wife that new tablesaw ....hmmmm
Adam, your inch and an eight plywood WILL add stiffness to the floor. I don't care what anyone else says here.
But that aside, your question is really, whether your floor is stiff enough for a tile application as is.
I would plug in your specs to a Deflecto-Meter and find out. You will need the joist wood type (grade of pine or fir); the dimensional size (like 2x6 or 2x8 etc); the span of the joists (how long of an uninterrupted span they cross); the underlayment (which is probably 1x6 doug fir, right?) and finally whether the flooring is tile (which is an L360 standard) or stone (which is an L720 standard); then press the magic button, and through the miracle of science, you will discover whether your floor is OK for tile.
I didn't run your specs through the Deflecto-Meter, but would suspect that you need to add at least another 3/4" of plywood, and maybe the inch and an eight variety to stiffen up the floor.
Here is the Deflecto-Meter:
http://johnbridge.com/vbulletin/deflecto.pl
Let us know how it turns out.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934