new construction to old,leveling out floor

[angrymime666]

original floor joists are actual 2 x 6 with an 11 foot span.

2 layers of 3/4 inch t&g plank. I will also most likely be adding another 1/2 of ply, then slc, ditra and tile. I was thinking of either 12 x 24 or 16 x 16 or 18 x 18 tile. Im not exactly sure at this point since Im still working on structure.

thanks

G

[MarkMc]

Because it's easier....

go here

http://www.johnbridge.com/vbulletin/deflecto.pl

[TSJHD1]

Don't know if this would be feasible in your situation, but I'm thinking removal of the old floor. Demo to the joists for a couple reasons: One, I'm leery of the 2x6 over an 11' span for a tile floor. Opening up the floor would enable you to sister 2x8's. (You did say existing subfloor is 1.5", and you plan to add plywood on top of that, correct?) And secondly, you can get the new and old floors nice and level and in-plane as you set the new joists.

Whatever route you take, you must account for new framing mating to existing, in that it will do some shrinking. You don't want to be able to tell where the new meets the old in the final product. And with a tile floor, that could come in the form of a joint crack.

Tom

[angrymime666]

Don't know if this would be feasible in your situation, but I'm thinking removal of the old floor. Demo to the joists for a couple reasons: One, I'm leery of the 2x6 over an 11' span for a tile floor. Opening up the floor would enable you to sister 2x8's. (You did say existing subfloor is 1.5", and you plan to add plywood on top of that, correct?) And secondly, you can get the new and old floors nice and level and in-plane as you set the new joists.

Whatever route you take, you must account for new framing mating to existing, in that it will do some shrinking. You don't want to be able to tell where the new meets the old in the final product. And with a tile floor, that could come in the form of a joint crack.

Tom

thanks for the reply. sistering 2 x 8 is out of the question since that would throw off the entire main level. I do have access to the floor from the basement so I could sister a 2 x 6 to the existing 2 x 6. The original joist is an actual 2 x 6 not 1.5 x 5.5, not sure if that would make that much of a difference.

G

[angrymime666]

Because it's easier....

go here

http://www.johnbridge.com/vbulletin/deflecto.pl

thanks for the link:

heres the what it came up with.

For joists that are SYP or Douglas Fir, in good condition, 6 inches tall, 2 inches wide, 18 inches on center, and 10.5 feet long between supports, the deflection calculated is 0.408 inches.

This translates to a deflection of L / 309.

Since the maximum deflection for tile is L / 360, and for natural stone is L / 720, your floor is rated for Sheet Vinyl or wood.

[angrymime666]

I guess I will be sistering. I inputed the added 2 x 6 and I got numbers that would carry the load of the tile.

[m beezo]

sistering seems like a smart thing to do. You going to put all the work into the tile and then have it fail is not going to make anyone happy so a little extra effort first is probably going to pay off. I say probably because as was pointed out you may have problem with the new materials shrinking.