Unlevel floor

[CoryPollard]

I have been lurking around here for a few days reading everything that I can, and I must say that this is the most helpful forum I have ever seen. I am impressed! I am remodeling my small master bath, it is 6'x9' with a 3'x3' shower pan in one corner. There is an unfinished basement underneath the bathroom, starting at the far wall the first floor joist sits on a concrete foundation wall, the next 2 or 3 span 10' to a wall, then the last 1 or 2 joists span about 18'. The joists are 9.25" tall "I" beam type joist and are 24" on center. The original subfloor is some type of MDF but it has an orange color to it. On top of that is 3/8" underlayment for the vinyl that was on the floor. Here is the real problem, which I never noticed when it had vinyl on it. In the last 3 feet of the floor against the wall, it rises nearly 5/8. I had to set the shower pan in thinset, and the edge if it is nearly 5/8" off of the floor. I understand it is not the best, but will this work for tile? I have 5/8" CDX plywood on hand to lay down, but I would rather not because of heighth. I am not looking for guarrantee's or to blame somebody if it doesn't work, but just honest opinions so that I can make a decision about it.

Thank you

[Old World Tile and Marble]

can you get a picture of the offending area and maybe some pics of the floor with a straight edge laid across it in a couple places?

[Rd Tile]

Did you remove the 3/8" and the vinyl yet?

You need 2 layers of wood over that 24" spacing and CDX is garbage, I would mud the floor to get it level and flat.

[CoryPollard]

Sure thing, here are the joists, the nearest ones are the ones that span the farthest, this is the same view as looking from the bathroom door, just from underneath. The original subfloor is some type of comp and is 7/8-1 inch thick. The ramp up isn't noticable under foot, I didn't know it was like this until I started to set the pan. Yes the vinyl has been removed (fire) but the 3/8 is still there becuase it is stapled ever 2 inches it seems.

Cory

[Supergirl]

Just a thought that jumped out at me while reading your post- as I went through this when prepping for my bath...

Where the joists span 18', have you checked if the floor is rated for tile? I think that may be too much deflection?

Just check the Deflecto tool, look to the top of this page in the blue header...

[Rd Tile]

I-Joists, deflecto no workie for those.

They can handle longer spans, there's site somewhere that has the specs on them, forgot it, have to look it up.

[cx]

Welcome, Cory.

Originally Posted by Cory

The original subfloor is some type of MDF but it has an orange color to it.

Think we've heard of some sort of orange-lookin' flooring up yonder in Canuckistan. That where y'all are? See can you find a stamp on that subflooring somewhere to help identify it. The thickness is unusual and leads to speculation about it having been wet sometime in its life.

It's unusualy for engineered floor systems to be designed below the code-required L/360 deflection, but it could happen, I suppose. It's more common for them to be designed to L/480, 'specially in longer spans, but yours don't look heavy enough to get there with that spacing. That's a guess, of course.

Try to find a manufacturer's stamp on one of those joists and contact them. That's the only real way to determine what you've got for design deflection.

Originally Posted by Cory

Yes the vinyl has been removed (fire) but the 3/8 is still there becuase it is stapled ever 2 inches it seems.

Ain't nobody promised you easy, eh?

I doubt the underlayment is really 3/8ths plywood of suitable characteristics for a ceramic tile installation, but I suppose that's possible, too. Almost certain it's gotta come out, though.

And with the unknown properties of the existing subfloor, I'd not want to tile without adding a suitable layer of plywood over what you've got. I'd recommend a half-inch minimum thickness.

On your shower pan dilema, my recommendation, if you are not going to fix the underlying problem, would be to abandon the pre-fab receptor and build your own shower pan. Either a traditional pan, or a Kerdi System pan. Either one would permit you to disregard the sloped floor inside the shower area. Might look a little funny from the outside, though, but no funnier than that pre-fab jacked up on one end.

My opinion; worth price charged.

[CoryPollard]

Well I didn't know about this forum when I started this project, and I knew that a fiberglass pan wouldn't leak, so I went with it, I am planning on putting some tile on the face of the curb to hide the raised edge. It will look a little strange, but its what I have to deal with. I will do some more research on the floor/joists.